When Should I Schedule QII Verification?

When Should I Schedule QII Verification

When Should I Schedule QII Verification?

Call (626) 365-1518 | Alternative Energy Systems

When Should I Schedule QII Verification should be answered before insulation, drywall, tubs, showers, cabinets, exterior finishes, or other construction begins concealing the parts of the building envelope that need to be inspected.

The safest approach is to identify the QII requirement during the planning or permit stage and contact the appropriate rater before construction reaches the first verification point.

For a current project using the 2025 California Energy Code, required residential field verification is performed through the Energy Code Compliance Program by an appropriately qualified ECC Rater. Projects governed by earlier Energy Code cycles can still use HERS terminology and HERS-related documentation.

A typical QII schedule includes two important construction stages:

  • Framing and air-infiltration-sealing verification before insulation conceals the applicable conditions
  • Insulation-installation verification while the insulation remains visible and accessible

Waiting until the project is ready for drywall can create a serious scheduling problem because some required air-barrier and insulation conditions may already be hidden.

The project team should therefore review the Certificate of Compliance early, determine whether QII field verification is required, and coordinate the rater with the construction schedule.

Alternative Energy Systems can review the Title 24 calculations and help identify whether QII is included in the energy-compliance design. Required third-party field verification is a separate construction-stage service performed by the applicable rater.

Call (626) 365-1518 if QII appears on your energy report and you need help understanding when the verification should be coordinated.

The Best Time to Plan QII Verification Is Before Construction Reaches Insulation

QII should not be treated as an inspection that can be arranged at the very end of construction.

The process evaluates work that becomes concealed as construction advances.

That means scheduling should begin before the affected work becomes inaccessible.

Check the Certificate of Compliance First

The Certificate of Compliance identifies field-verification measures associated with the approved energy design.

Before scheduling anything, determine whether the project actually identifies QII as a required measure.

Useful documents can include:

  • Certificate of Compliance
  • Title 24 calculations
  • Current construction plans
  • Insulation specifications
  • Existing ECC or HERS documentation

If QII is listed, the construction team should know about it before framing, air sealing, and insulation schedules are finalized.

Do Not Wait Until the Insulation Contractor Is Already on Site

Calling a rater after insulation installation has already started can make coordination more difficult.

The rater may need access to conditions that should have been reviewed before insulation was placed.

Early scheduling gives the contractor time to coordinate the applicable framing-stage verification without stopping work unexpectedly.

Tell the Framing and Insulation Contractors About QII

The people performing the work should know that the project includes third-party verification.

This allows them to plan for:

  • Air sealing
  • Hard-to-access cavities
  • Exterior-wall conditions
  • Attic details
  • Insulation around plumbing and wiring
  • Access for the rater
  • Correction of deficiencies before concealment

QII is much easier to manage when it is incorporated into the construction schedule instead of discovered after the work is finished.

Identify the Applicable Energy Code Version

Code cycle matters because California changed the terminology used for residential field verification beginning with the 2025 Energy Code.

Applicable permit applications filed on or after January 1, 2026 generally use the 2025 Energy Code.

Current 2025 documentation uses ECC terminology, while older code-cycle projects can still display HERS terminology.

Review Which Title 24 Energy Code Version Do I Need if the applicable code cycle is unclear.

When Should I Schedule QII Verification framing stage

Schedule the First QII Verification Before Insulation Conceals the Framing

Air-Infiltration Sealing and Air Barriers Need to Remain Visible

The first major QII scheduling point is associated with the framing and air-sealing stage.

Current California single-family compliance documents include a specific QII Air Infiltration Sealing – Framing Stage verification form.

The purpose is to confirm applicable air-barrier and sealing conditions while they can still be inspected.

When Is the Framing Stage Ready?

The correct timing depends on the project, but the applicable framing and air-sealing work should be sufficiently complete for inspection while remaining visible.

The rater may need to evaluate applicable conditions involving:

  • Exterior walls
  • Ceilings
  • Raised floors
  • Garage interfaces
  • Kneewalls
  • Attic boundaries
  • Utility penetrations
  • Other boundaries between conditioned and unconditioned space

Should Insulation Be Installed Before the Framing-Stage Verification?

Do not assume it should.

The current QII insulation-verification documentation specifically recognizes that applicable air-barrier installation and preparation for insulation are verified before insulation installation.

Coordinate the actual sequence with the rater so required framing-stage conditions are not hidden prematurely.

What Should Be Complete Before the Rater Arrives?

Applicable air-sealing work should be ready enough to evaluate.

Potential areas can include penetrations involving:

  • Plumbing
  • Electrical wiring
  • Mechanical systems
  • Framing transitions
  • Other envelope openings

The exact checklist depends on the building and construction assemblies.

What Should Remain Open?

Any applicable condition that the rater needs to verify should remain accessible.

Avoid covering required inspection areas with:

  • Insulation installed too early
  • Drywall
  • Paneling
  • Permanent interior finishes
  • Other materials that prevent verification

Schedule Around Tubs and Showers When They Affect Exterior Walls

Tubs and shower assemblies installed against exterior walls can make insulation and air-barrier areas difficult to access later.

When applicable, those wall conditions should be coordinated before the enclosure blocks access.

Schedule Around Stairwells and Fireplaces

Similar problems can occur where exterior-envelope areas become concealed behind:

  • Fireplace assemblies
  • Stairwells
  • Architectural chases
  • Other permanent construction

The project team should identify these areas before they become inaccessible.

Hard-to-Access Cavities Should Be Planned Early

Wall intersections, corner channels, and other difficult framing cavities can become impossible to insulate correctly after later construction is installed.

These conditions should be coordinated as part of the framing and insulation schedule rather than treated as last-minute details.

When Should I Schedule QII Verification insulation stage

Schedule the Insulation-Stage Verification Before Drywall

The Rater Needs to See the Installed Insulation Before It Is Concealed

The second major QII scheduling point occurs after the applicable insulation has been installed but before drywall or other finishes prevent inspection.

This is when the rater can evaluate whether the installed insulation corresponds to the energy-compliance documentation and applicable QII criteria.

What Should Be Ready for the Insulation Verification?

The applicable insulation installation should be complete enough for the rater to inspect the required areas.

Depending on the project, this can include:

  • Exterior-wall insulation
  • Ceiling insulation
  • Roof-deck insulation
  • Raised-floor insulation
  • Kneewall insulation
  • Skylight-shaft insulation
  • Other applicable envelope surfaces

Do Not Schedule Drywall for the Same Time Without Coordination

Drywall can quickly conceal the conditions that need to be verified.

The safest construction sequence allows enough time for:

  • Rater inspection
  • Correction of any deficiencies
  • Reverification when necessary
  • Drywall installation after the required verification has been completed

Scheduling trades too tightly can turn a minor insulation correction into a larger construction delay.

Allow Time for Corrections

A project should not assume the first inspection will automatically result in every item passing.

If the rater identifies a deficiency, the contractor may need time to correct:

  • Gaps
  • Voids
  • Compression
  • Missing insulation
  • Improper fitting around wiring
  • Improper fitting around plumbing
  • Incomplete air barriers
  • Other applicable conditions

A small amount of schedule flexibility can prevent drywall or finish trades from arriving before the envelope work is ready.

Insulation Labels Should Be Available

The current California QII insulation-verification form requires applicable insulation product labels or specification information to be provided to the ECC Rater.

For loose-fill products, manufacturer coverage information can also be needed.

Do not wait until inspection day to begin searching for product information.

Loose-Fill Insulation May Need Depth and Density Verification

Applicable loose-fill installations include additional verification criteria.

The rater may need to evaluate installed depth and density at multiple locations against the required R-value and manufacturer coverage information.

The insulation should therefore be complete enough to evaluate while the required indicators remain visible.

Do Not Remove Attic Depth Markers Before Verification

Where attic rulers or other applicable depth indicators are required, they should remain available so the installed insulation can be evaluated.

Make Sure the Installed R-Values Match the Approved Design

Before scheduling the rater, compare the installed insulation with the Certificate of Compliance.

If the contractor has substituted another product or changed an assembly, ask whether the Title 24 documentation needs to be reviewed before verification.

When Should I Schedule QII Verification before drywall

Do Not Let Drywall Get Ahead of QII Verification

Concealing Required Inspection Areas Too Soon Can Create Avoidable Problems

One of the most important scheduling rules is simple: do not intentionally conceal work that still requires verification.

QII focuses on physical construction conditions.

Once the wall or ceiling is closed, the rater may no longer be able to see what needs to be verified.

Can Drywall Be Delivered Before the Inspection?

Material delivery by itself is generally a construction-management issue.

The critical concern is whether drywall or another finish is actually installed over areas that still require verification.

Coordinate the sequencing with the rater and contractor before closing the assemblies.

What if the Drywall Crew Is Already Scheduled?

Confirm the QII verification status before allowing work to proceed.

If required verification remains incomplete, rescheduling a finish trade may be less disruptive than opening completed construction later.

What if Some Walls Are Ready and Others Are Not?

Ask the rater how the project should be coordinated.

Do not independently assume that partial closure is acceptable if required inspection areas are involved.

Large projects can have more complicated sequencing, so communication becomes especially important.

What if Exterior Finishes Will Hide a Cavity?

QII scheduling is not only about interior drywall.

Exterior sheathing, siding, stucco systems, roofing work, and other construction can also make certain envelope areas inaccessible.

Hard-to-reach cavities should be addressed before construction prevents access.

What About Cabinets?

Cabinets can conceal wall areas after drywall has already been installed.

The larger issue is that QII wall verification should normally be coordinated before the wall cavity is closed in the first place.

What About Built-In Tubs and Showers?

When these assemblies affect exterior-envelope access, their installation schedule may need to account for insulation and air-barrier work.

What About Spray Foam?

Spray polyurethane foam installations should also be coordinated with the required inspection sequence.

The product should be installed according to manufacturer instructions and the approved energy design.

Do not assume that using spray foam eliminates QII verification when QII is listed on the compliance documents.

When Should I Schedule QII Verification for attic insulation

Coordinate Attic QII Verification With the Actual Attic Design

Vented and Unvented Attics Can Require Different Construction Timing

Attic insulation can be installed at different stages depending on the roof-and-ceiling assembly.

The QII schedule should therefore reflect the actual attic design rather than a generic construction sequence.

When Should Ceiling Insulation Be Verified?

Applicable ceiling insulation should remain accessible long enough for required verification.

The rater can evaluate conditions involving:

  • Insulation contact with the ceiling air barrier
  • Gaps
  • Voids
  • Compression
  • Attic access insulation
  • Eave conditions
  • Loose-fill depth

When Should Attic Access Insulation Be Installed?

The attic-access assembly should be coordinated so the required insulation and applicable insulation dam can be verified.

Do not leave required attic-access details unfinished while expecting the remainder of the attic to receive final verification.

When Should Eave Baffles Be Installed?

Applicable baffles or dams should be installed before loose-fill or batt insulation makes the eave areas difficult to inspect or correct.

Required ventilation openings should remain unobstructed.

What About Loose-Fill Attic Insulation?

Schedule verification when the installation is complete enough for the rater to evaluate the required depth and density conditions.

Keep applicable product information and depth indicators available.

What About an Unvented Attic?

An unvented attic has different air-barrier and insulation relationships from a conventional vented attic.

Roof-deck insulation, gable-end conditions, and other applicable components should be coordinated according to the approved design.

Do not schedule based on assumptions from a different attic configuration.

What About a High-Performance Attic?

High-performance attic designs can involve specific combinations of insulation, roof-deck measures, ducts, ventilation, and other energy features.

The QII schedule should correspond to the actual measures shown in the Title 24 documentation.

Should HVAC Duct Installation Be Coordinated Too?

Yes when ductwork affects access to insulation or envelope assemblies.

Mechanical systems can make attic or framing areas harder to reach after installation.

Construction sequencing should preserve access for the work and verification that still need to occur.

When Should I Schedule QII Verification ECC Rater

Schedule the ECC Rater Early Enough to Protect the Construction Timeline

Current 2025 Projects Use California’s Energy Code Compliance Program

For current 2025 Energy Code projects, California uses the Energy Code Compliance Program for applicable residential field verification and diagnostic testing.

The program is administered through approved ECC Providers, which train and oversee ECC Raters and operate residential data registries.

For official program information, review the California Energy Commission Energy Code Compliance Program.

How Far in Advance Should I Contact the Rater?

There is no universal number of days that applies to every company, project, or construction schedule.

Availability can vary.

The better rule is to contact the rater well before the project reaches the first required verification stage rather than waiting until the day the inspection is needed.

Should I Hire the Rater During Plan Review?

You can identify and coordinate the rater early once you know the project requires field verification.

The actual construction-stage inspections occur later, but early coordination can help prevent confusion about:

  • Required stages
  • Access
  • Scheduling
  • Documentation
  • Project registry requirements

Who Is Responsible for Scheduling the Rater?

Responsibility can depend on the construction contract and project team.

The building owner, builder, contractor, or another responsible participant should make sure required field verification is coordinated.

Do not assume the building department or Title 24 consultant automatically schedules the rater unless that service is expressly included in the project agreement.

Does AES Schedule the ECC Rater?

Alternative Energy Systems prepares energy-compliance documentation and can identify verification requirements associated with the Title 24 design.

Third-party field verification is a separate service unless the project agreement specifically states otherwise.

Does the Building Department Schedule QII?

No assumption should be made that the building department will arrange third-party Energy Code verification for the project.

Building-department inspections and ECC field verification are separate compliance functions.

What if My Project Still Uses HERS Terminology?

Earlier Energy Code cycles can continue using HERS terminology on their compliance documentation.

The California Energy Commission confirms that 2025 Energy Code documentation uses ECC terminology while older code-cycle forms continue to display HERS references.

The applicable code version should be confirmed before scheduling the wrong type of documentation.

When Should I Schedule QII Verification after missed inspection

What if I Waited Too Long to Schedule QII Verification?

Stop Before Concealing More Work and Review the Compliance Requirements

If the project has advanced farther than expected, do not assume the QII requirement disappears.

The next step depends on what has already been constructed and which verification stage was missed.

What if Insulation Is Installed but Not Yet Covered?

Contact the rater promptly.

The insulation may still be accessible for the applicable insulation-stage verification, but any earlier framing-stage requirement also needs to be addressed through the proper compliance process.

What if Drywall Has Already Been Installed?

Contact the rater and energy consultant before proceeding further.

Do not assume the project can simply submit photographs or contractor statements in place of required verification.

Some conditions may no longer be visible.

Can Photographs Solve a Missed Inspection?

Do not rely on photographs as an automatic substitute.

Required field verification must follow the applicable California procedures and ECC Provider requirements.

The rater determines what can be verified under the program rules.

Can QII Be Removed Instead?

Potentially, but only if the energy design can be revised and still demonstrate compliance.

If QII was used in a performance calculation, removing it can reduce the modeled thermal performance of the building envelope.

Other efficiency measures may be required to compensate.

Should Construction Continue While QII Is Unresolved?

Avoid concealing additional affected work until the project team understands what still needs to be verified.

Continuing construction without resolving the issue can make later corrections more difficult.

What if the Rater Finds a Deficiency?

The ECC Program requires failed measures to be corrected until they satisfy the applicable compliance threshold.

Potential correction items can include:

  • Missing insulation
  • Gaps
  • Voids
  • Compression
  • Incomplete air sealing
  • Incorrect materials
  • Installation that does not match the Certificate of Compliance

Building some correction time into the schedule can keep one failed item from disrupting every trade that follows.

Does Reinspection Add Time?

It can.

The amount of additional time depends on the deficiency, repair, rater availability, and project schedule.

This is another reason early coordination is preferable to treating QII as a last-minute inspection.

Can Plan Changes Affect QII Scheduling?

Yes.

If the project changes:

  • Wall assemblies
  • Roof assemblies
  • Insulation levels
  • Conditioned floor area
  • Attic configuration
  • Other envelope features

the energy documentation may need to be reviewed before construction continues.

Do not schedule verification around an outdated energy report when the plans have materially changed.

Should I Send Revised Plans to AES?

Yes when design changes affect the energy analysis.

AES can compare the revised construction with the current Title 24 documentation and determine whether updated calculations or forms are needed.

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides professional Title 24 calculations, compliance documentation, revisions, and energy-related plan-check support throughout California.

AES brings more than 30 years of California energy-compliance experience to:

  • New homes
  • ADUs
  • Garage conversions
  • Additions
  • Residential remodels
  • Multifamily projects
  • Envelope-compliance projects
  • Projects involving QII
  • Plan-check corrections
  • Energy-report revisions

AES can identify QII requirements in the energy documentation and help keep the calculations coordinated with the current plans. Required third-party field verification is performed separately by the applicable rater unless the project agreement expressly states otherwise.

Learn more through the About Us page, review company background on the clients page, or explore Title 24 energy compliance.

Frequently Asked Questions: When Should I Schedule QII Verification?

When Should I Schedule QII Verification?

Begin coordinating QII verification before the project reaches insulation. The framing and air-sealing stage should be addressed before applicable conditions are concealed, followed by insulation verification while the insulation remains accessible.

Should I contact the rater before insulation is installed?

Yes. Early contact helps coordinate the framing-stage air-sealing verification that can need to occur before insulation hides the applicable conditions.

When should the framing-stage QII inspection happen?

It should be coordinated when applicable framing and air-sealing work is ready for verification but before insulation or other construction prevents inspection.

When should the insulation-stage verification happen?

After the applicable insulation is installed and ready for inspection but before drywall or other finishes conceal it.

Should I schedule drywall before the QII inspection?

Do not allow drywall to conceal required inspection areas before the applicable verification has been completed.

How many QII stages are there?

Current California single-family QII documentation includes separate framing-stage air-infiltration-sealing and insulation-installation verification forms.

Can QII be inspected after insulation is installed?

The insulation stage is inspected after installation, but applicable framing-stage and air-barrier verification must also be coordinated at the proper time.

Can QII be inspected after drywall?

Required conditions should remain visible and accessible. Drywall can make required verification impossible or significantly more difficult.

Can I schedule QII on the same day as drywall?

That creates unnecessary risk if corrections are needed. Allow enough time for inspection and any required repairs before finishes conceal the work.

How far in advance should I contact an ECC Rater?

There is no universal number of days. Contact the rater well before the first required verification stage because availability and project complexity vary.

Should I coordinate the rater during plan review?

Early identification can be helpful once the Certificate of Compliance shows that field verification is required, even though the actual inspections occur during construction.

Who schedules the ECC Rater?

Responsibility depends on the project arrangement. The owner, builder, contractor, or another responsible participant should ensure required verification is scheduled.

Does AES automatically schedule the rater?

Do not assume so. AES prepares energy-compliance documentation and can identify required measures, while third-party verification is a separate service unless specifically included in the project agreement.

Does the building department schedule QII?

Building-department inspections and ECC field verification are different processes. Do not assume the jurisdiction schedules the project’s ECC Rater.

When should attic insulation be inspected?

Schedule it when the applicable attic insulation and related details are complete enough for verification while remaining accessible.

Should loose-fill insulation be complete before the inspection?

It should be installed to the stage required for the rater to evaluate applicable depth, density, product information, and other QII criteria.

Do insulation labels need to be available at inspection?

Yes. Current QII criteria require applicable insulation labels or specification sheets to be provided to the ECC Rater.

What if the rater finds a problem?

The contractor should correct the applicable deficiency and complete the required verification before the affected work is concealed.

What if I already installed drywall?

Contact the rater and energy consultant before proceeding further. Do not assume photographs or contractor statements automatically replace required field verification.

Can I remove QII if I missed the inspection?

Potentially only through a revised compliant energy analysis. Removing QII can change the modeled envelope performance and may require other efficiency measures.

What if my Title 24 report says HERS instead of ECC?

The project may be governed by an earlier Energy Code cycle. Older compliance documents can still use HERS terminology, while 2025-code projects use ECC terminology.

What should I send AES if I need scheduling guidance?

Send the current plans, Certificate of Compliance, Title 24 calculations, insulation specifications, applicable ECC or HERS documents, and the current construction stage.

How do I get help understanding my QII schedule?

Call Alternative Energy Systems at (626) 365-1518, email info@title24energy.com, or use the contact page.

When service and payment have already been arranged, payment can be completed through the AES payment page.

How Do I Pass a QII Inspection?

How Do I Pass a QII Inspection

How Do I Pass a QII Inspection?

Call (626) 365-1518 | Alternative Energy Systems

How Do I Pass a QII Inspection is a practical question that should be answered before insulation, drywall, or other finishes begin covering the building envelope.

Passing Quality Insulation Installation verification requires more than installing insulation with the correct R-value. The air barriers, insulation materials, framing cavities, penetrations, attic conditions, and other applicable portions of the envelope need to match the approved California energy-compliance design and satisfy the applicable QII installation criteria.

The most effective approach is to plan for QII before construction reaches the inspection stages.

For a current 2025 Energy Code project, the process generally involves an appropriately qualified Energy Code Compliance Rater, commonly called an ECC Rater. Older projects can still contain HERS terminology because earlier Energy Code cycles used HERS field-verification procedures.

To improve the likelihood of passing the applicable QII verification:

  • Confirm that QII is listed in the approved energy documentation.
  • Review the insulation levels shown on the Certificate of Compliance.
  • Coordinate with the ECC Rater before work is concealed.
  • Complete required air sealing before insulation is installed.
  • Install insulation according to manufacturer instructions.
  • Avoid gaps, voids, and improper compression.
  • Fit insulation carefully around wiring, plumbing, electrical boxes, and structural elements.
  • Complete hard-to-access cavities before they become inaccessible.
  • Maintain required attic ventilation and insulation conditions.
  • Keep insulation labels and specification sheets available for verification.
  • Correct deficiencies before drywall or other finishes hide the work.

Alternative Energy Systems can review the Title 24 calculations and help identify which QII measures appear in the approved compliance design. Required third-party field verification is performed separately by the applicable rater.

Call (626) 365-1518 if QII appears on your project and you need help understanding how the energy report relates to the construction requirements.

Start by Confirming That QII Is Actually Part of the Project

Before preparing for an inspection, verify that the approved Title 24 documentation actually requires QII.

Useful documents can include:

  • Certificate of Compliance
  • Title 24 energy calculations
  • Construction plans
  • Insulation specifications
  • Existing ECC or HERS documentation

The project should not rely on verbal assumptions about whether QII applies.

Review the Certificate of Compliance Before Insulation Begins

The Certificate of Compliance identifies energy-related assumptions used in the approved design.

The installed insulation should meet or exceed the applicable levels represented in that documentation.

Before the insulation contractor begins work, the project team should understand:

  • Wall insulation requirements
  • Ceiling insulation requirements
  • Roof-deck insulation when applicable
  • Raised-floor insulation when applicable
  • Slab-edge insulation when applicable
  • Other QII measures identified for the project

If the construction documents and energy report disagree, resolve the discrepancy before relying on either version in the field.

Do Not Wait Until the Insulation Is Finished to Call the Rater

QII involves construction conditions that can become hidden.

The rater should therefore be coordinated before the applicable work is concealed.

Waiting until drywall is scheduled can be too late to easily verify some of the required air-barrier and insulation conditions.

Understand That QII Includes More Than One Stage

Current California single-family QII documentation separates the process into major stages that include:

  • Air-infiltration sealing at the framing stage
  • Insulation installation verification

The project team should schedule construction around those verification points.

For general information about insulation and thermal-envelope performance, review building insulation on Wikipedia.

How Do I Pass a QII Inspection framing stage

Pass the Framing and Air-Sealing Stage First

Required Air Barriers Should Be Verified Before Insulation Is Installed

A major step in answering How Do I Pass a QII Inspection is understanding that the process begins before the insulation is placed into the framing cavities.

The current QII insulation verification form specifically requires confirmation that air-barrier installation and preparation for insulation were completed and verified before insulation installation.

Seal Applicable Boundaries Between Conditioned and Unconditioned Space

The building envelope separates conditioned space from areas that are outside the conditioned environment.

Potential boundaries can include:

  • Exterior walls
  • Ceilings
  • Roof assemblies
  • Raised floors
  • Garage interfaces
  • Kneewalls
  • Skylight shafts
  • Other project-specific assemblies

Applicable air barriers and sealing should be complete enough for verification before insulation covers the work.

Pay Attention to Plumbing and Electrical Penetrations

Air leakage can occur around penetrations through the envelope.

Common areas requiring careful workmanship can include:

  • Plumbing lines
  • Electrical wiring
  • Electrical boxes
  • Mechanical penetrations
  • Framing transitions
  • Other utility openings

The goal is a continuous applicable air barrier rather than isolated patches of sealant with large unaddressed openings elsewhere.

Check Framing Intersections Before They Become Inaccessible

Some framing configurations become difficult to reach after sheathing, stucco lath, drywall, tubs, showers, or other construction is installed.

These areas should be addressed while access remains available.

Coordinate Structural Framing With the Insulation Plan

Structural components can create thermal bridges and difficult insulation conditions.

The current QII criteria recognize structural bracing, tie-downs, steel framing, and other specialized framing, but applicable areas still need to be insulated according to the required design.

When unusual structural conditions affect the envelope, the plans should clearly identify the insulation strategy.

Do Not Cover the Framing Before Required Verification

If the rater needs to inspect an air barrier or framing condition, concealing it prematurely can create a compliance problem.

Construction scheduling should account for:

  • Framing completion
  • Air sealing
  • Applicable rater verification
  • Insulation installation
  • Insulation verification
  • Drywall or other interior finishes

That sequence can vary according to the project, but the required work should remain visible when it needs to be inspected.

How Do I Pass a QII Inspection insulation installation

Install the Insulation to the QII Standard

Correct R-Value Alone Is Not Enough to Pass Verification

Once the framing and applicable air barrier are ready, the insulation itself becomes the focus.

The current California verification criteria require insulation to be installed according to the manufacturer’s instructions and to correspond with the Certificate of Compliance.

Avoid Gaps in Insulation

Insulation should fill the applicable cavity rather than leaving open areas that allow heat to bypass the intended thermal layer.

For applicable wall installations, the current QII criteria specifically address insulation contact throughout the cavity without unacceptable gaps.

Avoid Voids Behind the Insulation

An insulation batt can appear complete from the front while still hiding an empty space behind it.

This can happen when insulation is not fitted correctly around:

  • Pipes
  • Wiring
  • Electrical boxes
  • Bracing
  • Other obstructions

Insulation should be cut or fitted appropriately around obstructions rather than simply pushed over them.

Avoid Excessive Compression

Compressing insulation into a cavity can reduce the effective thermal performance of the installed assembly.

The rater is not simply looking for material inside the wall. The installation needs to satisfy the applicable QII criteria.

Fit Insulation Around Electrical Boxes

Electrical boxes commonly create problem areas.

The insulation should fit snugly around the box without leaving unnecessary gaps or creating improper compression.

Fit Insulation Around Plumbing

Plumbing lines can divide framing cavities and make full insulation contact more difficult.

The installer should fit the material around the plumbing so the cavity remains properly insulated.

Fit Insulation Around Wiring

Electrical wiring passing horizontally or vertically through wall cavities should not create large empty areas in the insulation system.

The insulation should be installed around the wiring according to the product and applicable QII procedures.

Follow the Manufacturer’s Installation Instructions

The current QII verification form specifically requires the insulation to be installed according to manufacturer instructions.

Do not assume that one installation technique applies equally to:

  • Fiberglass batts
  • Loose-fill insulation
  • Rigid insulation
  • Spray polyurethane foam
  • Other insulation products

The material and assembly determine the proper installation method.

How Do I Pass a QII Inspection wall insulation

Walls Are One of the Most Detailed Parts of QII Verification

Corners, Headers, Tubs, Showers and Obstructions Need Special Attention

Wall insulation can appear straightforward until framing, utilities, structural components, and architectural features begin interrupting the cavities.

QII procedures address many of these conditions directly.

Insulate Hard-to-Access Wall Cavities Early

Current QII criteria identify hard-to-access framing areas such as corner channels and wall intersections.

Applicable cavities should be insulated to the proper level before exterior sheathing or other construction makes access difficult or impossible.

Check Exterior Walls Behind Tubs and Showers

Tubs and shower enclosures located against exterior walls can hide large portions of the thermal envelope.

Applicable insulation and interior air barriers should be installed before those assemblies prevent access.

Check Walls Behind Fireplaces and Stairwells

Applicable exterior-wall areas behind fireplace enclosures and stairwells also need to remain consistent with the approved insulation design.

These locations should not be overlooked merely because they will later be concealed by another construction feature.

Pay Attention to Window and Door Headers

Headers can interrupt the insulated wall assembly.

Current California QII criteria include specific insulation provisions for applicable single-member window and door headers.

The correct solution depends on:

  • Wall framing depth
  • Header width
  • Continuous exterior insulation when applicable
  • Approved construction details

Do not improvise the header insulation after framing is complete without checking the required assembly.

Make Sure Kneewalls Have Complete Air Barriers

Attic kneewalls separate conditioned and unconditioned spaces and can become significant weak points when insulation and air barriers are incomplete.

Applicable kneewalls should be insulated and enclosed according to the approved QII design.

Pay Attention to Skylight Shafts

Skylight shafts create vertical portions of the building envelope inside attic spaces.

Current QII criteria include special requirements for applicable skylight shafts and attic kneewalls.

The insulation should remain properly supported and in contact with the applicable air barrier.

Do Not Leave Open Cavities Behind Architectural Features

A cavity hidden by cabinetry, tubs, showers, fireplaces, stairs, or another finish is still part of the envelope when it separates conditioned and unconditioned space.

The fact that the area will not be visible after construction does not eliminate the insulation requirement.

How Do I Pass a QII Inspection attic insulation

Prepare the Attic Carefully for QII Verification

Insulation Depth, Ventilation, Access and Air-Barrier Contact Can All Matter

Attic assemblies have their own QII details.

The applicable requirements depend on whether the project uses:

  • A conventional vented attic
  • An unvented attic
  • A high-performance vented attic
  • Another approved roof-and-ceiling configuration

Keep Ceiling Insulation in Contact With the Air Barrier

Current QII criteria require applicable ceiling insulation to remain in direct contact with the ceiling air barrier without unacceptable gaps, voids, or compression.

An insulation layer that floats above the ceiling or leaves large empty areas does not represent the intended assembly.

Do Not Block Required Eave Ventilation

In applicable vented-attic designs, required eave ventilation should remain unobstructed.

Insulation should not simply be pushed into ventilation openings.

Install Baffles and Insulation Dams Correctly

Where required, eave vent baffles and dams can help prevent insulation from obstructing ventilation or being displaced by airflow.

These details should be completed before the rater evaluates the attic assembly.

Insulate the Attic Access

Under the applicable current QII criteria, attic access needs insulation corresponding to the required ceiling insulation and the insulation needs to remain permanently attached.

The opening also requires the applicable insulation dam.

Install Loose-Fill Depth Markers When Required

For applicable loose-fill attic insulation, current QII verification uses attic rulers to document installed depth.

The rulers should correspond to the insulation product and remain visible for verification.

Have Loose-Fill Product Information Available

Loose-fill installations need manufacturer coverage information so depth and density can be compared with the specified R-value.

The current QII form calls for insulation labels or specification sheets to be provided to the rater.

Unvented Attics Have Different Details

In an applicable unvented attic configuration, the roof sheathing can serve as part of the air-barrier system.

Insulation contact, roof-deck conditions, and applicable gable-end construction should follow the approved design.

Do not use vented-attic installation assumptions on an unvented-attic project.

How Do I Pass a QII Inspection ECC Rater

Coordinate With the ECC Rater Before the Inspection

Good Scheduling Can Prevent Avoidable QII Failures and Construction Delays

The rater is verifying installed conditions, not redesigning the building after the work is complete.

Clear coordination helps everyone understand when the project is ready for inspection.

Contact the Rater Before Work Is Concealed

The safest time to establish the verification schedule is before the critical construction stages begin.

The project team should understand when the rater needs access to:

  • Framing
  • Air barriers
  • Insulation
  • Attics
  • Raised floors
  • Other applicable envelope assemblies

Do Not Assume the Building Inspector Replaces the ECC Rater

A building-department inspection and Energy Code field verification serve different purposes.

When the Certificate of Compliance requires third-party QII verification, ordinary building inspection should not be assumed to satisfy that requirement.

Have Product Documentation Ready

The current QII form requires applicable insulation labels or product specification sheets to be available to the ECC Rater.

For loose-fill products, that can include:

  • Bag labels
  • Coverage charts
  • Other manufacturer information

Make Sure the Installed Product Matches the Plans

Substituting insulation can create problems if the installed system no longer matches the Certificate of Compliance.

Before changing:

  • Insulation type
  • R-value
  • Assembly thickness
  • Roof or wall configuration

have the change reviewed when it affects the approved energy design.

Walk the Project Before the Rater Arrives

A contractor or insulation installer can catch many obvious problems before the formal verification.

A practical preinspection walkthrough should look for:

  • Missing batts
  • Open cavities
  • Large gaps
  • Compressed insulation
  • Uninsulated electrical boxes
  • Poor fitting around plumbing
  • Poor fitting around wiring
  • Missing insulation behind tubs or showers
  • Incomplete kneewalls
  • Blocked attic vents
  • Uninsulated attic access
  • Unfinished hard-to-reach cavities

Correcting these items before the rater arrives can reduce unnecessary reinspection and schedule disruption.

Do Not Rely on Photographs as a Substitute for Scheduling

Photographs can be useful construction records, but the project team should not assume photographs automatically replace required ECC verification.

Coordinate with the rater before covering any condition that needs field verification.

Keep the Current Plans Available

The rater may need to compare installed conditions against the approved compliance documentation.

Using old drawings in the field can create confusion when the building has already been revised.

How Do I Pass a QII Inspection corrections and Title 24 help

What Happens if You Do Not Pass the QII Inspection?

Correct the Deficiency and Complete the Required Verification Process

A failed QII item does not necessarily mean the entire construction project has permanently failed.

The current California ECC process provides for failed verification items to be corrected.

If an ECC Rater determines that a required feature does not satisfy the applicable compliance threshold, the contractor is responsible for correcting the feature or system until it passes.

What Causes a QII Failure?

Potential reasons can include:

  • Missing insulation
  • Incorrect insulation level
  • Gaps
  • Voids
  • Improper compression
  • Incomplete air barriers
  • Insulation installed incorrectly around obstructions
  • Hard-to-access cavities left unfinished
  • Attic conditions that do not satisfy the applicable criteria
  • Installed materials that do not match the compliance documentation

The Rater Can Document Correction Notes

The current CF3R QII form includes verification status and correction-note fields.

If one or more applicable requirements are not met, the rater can identify the reason for failure so the project team knows what needs correction.

Correct Problems Before the Work Is Concealed

The easiest time to correct insulation is generally while the cavity remains open.

Repairs become more complicated after drywall, cabinets, exterior finishes, or other construction covers the affected areas.

Do Not Simply Remove QII From the Paperwork

If QII is part of the approved energy-compliance design, eliminating it can affect the Title 24 calculation.

A revised performance analysis may be needed to determine whether the building can comply without verified QII.

Other efficiency measures may need to compensate for the change.

Can AES Review the Energy Calculation if QII Becomes a Problem?

Yes. Alternative Energy Systems can review the approved compliance design and determine whether the calculation needs revision.

The available options depend on:

  • Building envelope
  • Insulation levels
  • Window performance
  • HVAC efficiency
  • Roof design
  • Other qualifying measures

A revised calculation does not guarantee that QII can always be removed.

Passing QII Does Not Replace Other Required Verification

A project can have multiple field-verification measures.

Depending on the design, those may involve:

  • QII
  • Duct leakage
  • Mechanical ventilation
  • Airflow
  • Equipment performance
  • Other applicable measures

Passing QII satisfies the applicable QII requirement, not every Energy Code requirement on the project.

Current Projects Use ECC Terminology

For the 2025 Energy Code, California uses the Energy Code Compliance Program for residential field verification and diagnostic testing.

The ECC Program replaces the Energy Code field-verification portion of the former HERS Program.

The California Energy Commission explains the current program on its Energy Code Compliance Program page.

What if My Project Still Says HERS?

Older code-cycle projects can continue to use HERS terminology and forms associated with their applicable Energy Code.

Do not change forms simply because the terminology changed for the 2025 code cycle.

Review Which Title 24 Energy Code Version Do I Need if the applicable code version is unclear.

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides professional Title 24 calculations, energy-compliance documentation, revisions, and energy-related plan-check support throughout California.

AES brings more than 30 years of California energy-compliance experience to:

  • New homes
  • ADUs
  • Garage conversions
  • Additions
  • Residential remodels
  • Multifamily projects
  • Envelope compliance
  • Projects involving QII
  • Plan-check corrections
  • Energy-report revisions

AES can identify QII in the energy documentation and help coordinate the approved compliance design with the plans. Required third-party field verification is performed separately by an appropriately qualified rater unless a project agreement expressly provides otherwise.

Learn more through the About Us page, review company background on the clients page, or explore Title 24 energy compliance.

Frequently Asked Questions: How Do I Pass a QII Inspection?

How Do I Pass a QII Inspection?

Coordinate with the rater early, complete applicable air sealing before insulation, install insulation according to the Certificate of Compliance and manufacturer instructions, avoid gaps, voids, and improper compression, and correct deficiencies before the work is concealed.

Should I call the rater before installing insulation?

Yes. The applicable QII process includes air-barrier and framing-stage requirements that need to be coordinated before insulation covers the work.

Does QII require an inspection before drywall?

Applicable insulation conditions need to remain accessible for required verification. Do not conceal the work before coordinating the inspection.

Does the insulation have to match the Title 24 report?

Yes. Applicable surfaces should meet or exceed the insulation levels identified in the Certificate of Compliance.

Can insulation have gaps?

Applicable QII criteria require proper cavity installation without unacceptable gaps or voids.

Can insulation be compressed?

Improper compression can cause an installation to fail applicable QII criteria.

Does insulation have to fit around electrical boxes?

Yes. Applicable wall insulation should fit around electrical boxes, plumbing, wiring, and other obstructions without unacceptable gaps, voids, or compression.

Do hard-to-access cavities need insulation?

Yes. Applicable hard-to-access wall cavities should be insulated before construction makes them inaccessible.

Does insulation behind a bathtub matter?

Yes when the applicable tub or shower is located against an exterior envelope wall. The required insulation and air barrier should be installed before the enclosure prevents access.

Does attic access need insulation?

Applicable current QII criteria require attic access insulation corresponding to the required ceiling insulation and an appropriate insulation dam.

Can attic insulation block the eave vents?

No. Required eave ventilation should remain unobstructed in applicable vented-attic assemblies.

Do I need insulation product labels?

Current QII verification requires applicable insulation labels or specification sheets to be available to the ECC Rater.

Does loose-fill insulation get measured?

Yes. Current QII procedures include applicable depth and density verification and use manufacturer coverage information.

Who performs the QII verification?

For current 2025 Energy Code projects, required third-party field verification is performed by an appropriately qualified ECC Rater.

Is an ECC Rater the same as a building inspector?

No. The ECC Rater performs required Energy Code field verification, while the building department performs its own permit inspections.

Is an ECC Rater the same as a HERS Rater?

The current ECC Program replaced the Energy Code field-verification portion of the HERS Program. Older code-cycle projects can still use HERS terminology.

What happens if I fail the QII inspection?

The rater can identify the deficient item, and the contractor must correct the applicable feature or system until it satisfies the required compliance criteria.

Can I just cover the insulation after it fails?

No. The deficiency should be corrected and the required verification completed before the affected work is concealed.

Can photographs replace the inspection?

Do not assume so. Coordinate directly with the applicable rater before concealing any condition that requires field verification.

Can I remove QII if passing becomes difficult?

Potentially only after energy-compliance review. Removing QII can change the performance calculation and may require other efficiency measures.

Does passing QII guarantee permit approval?

No. QII is one part of the California Energy Code compliance process. The complete project remains subject to other applicable permit and inspection requirements.

What should I send AES if I have a QII problem?

Send the current plans, Certificate of Compliance, Title 24 calculations, insulation specifications, available ECC or HERS documentation, correction notes, and a description of the current construction stage.

How do I get help before a QII inspection?

Call Alternative Energy Systems at (626) 365-1518, email info@title24energy.com, or use the contact page.

When service and payment have already been arranged, payment can be completed through the AES payment page.

Is QII Required in California?

Is QII Required in California

Is QII Required in California?

Call (626) 365-1518 | Alternative Energy Systems

Is QII Required in California depends on the building type, project size, Energy Code version, and whether the project uses the prescriptive or performance compliance method.

For projects subject to the 2025 California Building Energy Efficiency Standards, Quality Insulation Installation is a prescriptive requirement for many residential projects, but it is not a universal requirement for every permit in the state.

For single-family residential construction, the 2025 prescriptive requirements call for QII in all California climate zones for newly constructed buildings and additions greater than 700 square feet.

That does not mean QII must always be used when a project demonstrates compliance through the performance method. Under performance compliance, QII can be traded off against other energy-efficiency measures. When verified QII is not used, the approved compliance software reduces the modeled effectiveness of applicable insulation in the proposed design.

QII can also apply differently to:

  • New single-family homes
  • Detached ADUs
  • Attached ADUs
  • Residential additions
  • Residential alterations
  • Low-rise multifamily buildings
  • Performance-compliance projects

The answer should therefore come from the project’s actual Certificate of Compliance rather than from a general assumption that every insulated building needs third-party QII verification.

Alternative Energy Systems provides Title 24 calculations and California energy-compliance documentation for residential, multifamily, mixed-use, and commercial projects. AES can review the plans and compliance documentation to determine whether QII is included in the approved energy design.

Call (626) 365-1518 if QII appears on your plans, energy report, or correction notice and you need help understanding what is required.

What Does QII Mean?

QII stands for Quality Insulation Installation.

It is a California Energy Code compliance measure intended to verify that insulation and associated air barriers are installed according to specific quality requirements rather than assuming that the nominal insulation R-value alone represents actual building-envelope performance.

QII can address conditions involving:

  • Wall insulation
  • Ceiling insulation
  • Roof insulation
  • Raised-floor insulation
  • Air barriers
  • Air-sealing details
  • Insulation around wiring
  • Insulation around plumbing
  • Insulation around electrical boxes
  • Hard-to-access framing cavities
  • Kneewalls
  • Skylight shafts
  • Attic conditions

For general background about the role insulation plays in reducing building heat transfer, review building insulation on Wikipedia.

Why Does California Have QII Requirements?

The thermal performance of insulation depends heavily on how it is installed.

A wall cavity can contain insulation labeled with the correct R-value and still perform worse than expected if the insulation contains:

  • Large gaps
  • Voids
  • Excessive compression
  • Poor fitting around pipes
  • Poor fitting around wiring
  • Missing areas behind obstructions
  • Disconnected air barriers

QII is intended to connect the energy calculation with actual field installation quality.

QII Is More Than an Insulation Label Check

A QII inspection is not simply a matter of confirming that the installer purchased insulation with the R-value shown on the plans.

The applicable procedures can examine whether the insulation:

  • Fills the intended cavities
  • Fits around penetrations
  • Remains in contact with applicable air barriers
  • Avoids unacceptable gaps
  • Avoids unacceptable voids
  • Avoids improper compression
  • Matches the approved compliance documentation

This is why QII involves field verification during construction.

Is QII Required in California for new homes

QII Is a Prescriptive Requirement for New Single-Family Construction

The 2025 Energy Code Applies the Requirement Across California Climate Zones

For newly constructed single-family residential buildings using the 2025 prescriptive compliance approach, QII is included in the prescriptive requirements in all California climate zones.

The California Energy Commission’s 2025 Single-Family Residential Compliance Manual states that the prescriptive requirements call for QII in all climate zones for newly constructed buildings and additions greater than 700 square feet.

This means a new home following the prescriptive package should be designed and constructed with the applicable QII requirements incorporated into the project.

Does Climate Zone Eliminate QII for a New Single-Family Home?

Not under the standard 2025 single-family prescriptive requirement.

California contains 16 building climate zones, but the current single-family prescriptive QII requirement applies across those climate zones for newly constructed buildings.

Climate zone still affects many other Title 24 measures, including:

  • Roof assemblies
  • Window performance
  • HVAC requirements
  • Cool-roof provisions
  • Other prescriptive envelope measures

For more information about those regional differences, review why Title 24 standards vary by climate zone.

What Parts of a New Home Does QII Cover?

For applicable new-construction QII projects, current California procedures can apply to the building envelope as a whole.

That can include applicable:

  • Roof and ceiling assemblies
  • Exterior walls
  • Floors
  • Attic assemblies
  • Other boundaries between conditioned and unconditioned space

The detailed verification criteria depend on the construction assembly.

Who Verifies QII on a Current Project?

Current 2025 Energy Code projects use the Energy Code Compliance Program for required field verification and diagnostic testing.

An appropriately qualified ECC Rater performs the third-party verification required by the current compliance process.

The California Energy Commission replaced the Energy Code field-verification portion of the older HERS Program with the ECC Program beginning with the 2025 Energy Code. Older code-cycle documents can continue to use HERS terminology.

Does the Building Inspector Perform QII Verification?

The building department and third-party Energy Code rater perform different functions.

When a project requires ECC field verification of QII, normal building inspection should not be assumed to replace the required rater verification.

The required compliance documentation must be completed through the applicable Energy Code process.

Does the Energy Consultant Perform the QII Inspection?

Preparing the Title 24 calculations and performing the required third-party field verification are separate functions unless a specific service arrangement expressly provides otherwise.

AES can identify QII in the energy documentation and help coordinate the calculation with the construction plans. Required field verification is completed separately by an appropriately qualified rater.

Is QII Required in California for additions

Are Residential Additions Required to Use QII?

The 700-Square-Foot Threshold Is Important Under Prescriptive Compliance

For single-family additions, project size matters.

Under the 2025 prescriptive requirements, additions greater than 700 square feet are subject to QII.

An addition of 700 square feet or less has a prescriptive exception from that QII requirement.

This distinction is particularly important for:

  • Room additions
  • Second-story additions
  • Attached ADUs
  • Expanded conditioned living areas

Does an Addition of Exactly 700 Square Feet Require Prescriptive QII?

The current prescriptive language applies QII to additions greater than 700 square feet.

An addition at or below that threshold can qualify for the applicable prescriptive exception, subject to the remaining Energy Code requirements.

Can a Smaller Addition Still Have QII?

Yes.

The prescriptive exception does not prevent QII from being used as a performance-compliance measure.

If QII is modeled for compliance credit, the applicable air barrier and insulation installation still need the required third-party field verification.

Does the 700-Square-Foot Exception Mean Insulation Quality Does Not Matter?

No.

An exception from formal prescriptive QII verification does not eliminate applicable mandatory insulation requirements, manufacturer installation requirements, or other building-envelope provisions.

It means the project is not automatically subject to the specific prescriptive QII verification requirement solely because of the addition under that size threshold.

What About an Attached ADU?

An attached ADU constructed as an addition can be affected by the same project-scope and area rules.

The California Energy Commission specifically confirms that the prescriptive QII requirements do not apply to ADU additions of 700 square feet or less.

However, when QII is modeled for performance credit, an ECC Rater must verify the applicable air barrier and insulation installation.

What About a Detached ADU?

A newly constructed detached ADU is generally treated as a newly constructed residential building for applicable Energy Code requirements rather than merely as an addition to the existing house.

Its Title 24 documentation should therefore be reviewed as a new residential project.

For project-specific guidance, review ADU Title 24.

What About a Garage Conversion?

A garage conversion can involve newly conditioned space rather than a traditional building addition.

The correct treatment depends on how the project is classified under the Energy Code and what compliance method is used.

The project should be reviewed before assuming that the 700-square-foot addition exception automatically applies to every garage conversion.

Is QII Required in California performance compliance

Can Performance Compliance Avoid the Prescriptive QII Requirement?

QII Can Be Traded Off, but the Energy Model Accounts for the Difference

This is one of the most important distinctions when determining Is QII Required in California.

The California Energy Commission states that QII is not a mandatory requirement in the same sense as a mandatory measure that cannot be traded away.

When a single-family project uses the performance compliance method, QII can be traded off with other efficiency measures.

However, that does not mean the software simply ignores QII.

What Happens in the Energy Model if QII Is Not Used?

The 2025 compliance modeling rules assume verified QII in the standard design for applicable new single-family buildings and additions greater than 700 square feet.

If the proposed design does not pursue QII, the compliance software reduces the modeled effectiveness of applicable insulation.

The project then needs enough performance elsewhere to remain within the permitted energy budget.

Why Is There an Energy Penalty Without QII?

The modeling adjustment reflects the fact that ordinary field installation can contain construction defects that reduce thermal-envelope performance.

Potential problems include:

  • Insulation gaps
  • Voids
  • Compression
  • Open framing pathways
  • Incomplete air barriers

Verified QII allows the model to take credit for higher-quality installation.

Can Other Measures Offset Not Using QII?

Potentially.

Under the performance method, the project may be able to use other qualifying efficiency improvements to offset the modeled impact of not using verified QII.

Possible project characteristics can include:

  • Higher-performing windows
  • Improved insulation assemblies
  • More efficient HVAC equipment
  • Improved roof assemblies
  • Other qualifying energy measures

The specific tradeoff must be demonstrated through CEC-approved compliance software.

Can I Decide During Construction to Skip QII?

Do not make that decision solely in the field.

If the approved Certificate of Compliance assumes QII, eliminating the measure can change the performance calculation.

The energy consultant should review the project and determine whether a revised compliant design is available.

Can QII Be Removed After the Framing Inspection Was Missed?

Potentially, but only through appropriate compliance review.

If a required QII inspection was missed, the project should not simply delete the measure from the paperwork and continue.

A revised energy analysis may be needed, and other measures may need to compensate for the loss of QII credit.

Is Performance Compliance Always Easier Than QII Verification?

Not necessarily.

The better approach depends on:

  • Building design
  • Envelope performance
  • Equipment efficiency
  • Construction schedule
  • Available tradeoffs
  • Cost of alternate efficiency measures

Sometimes keeping QII can be more practical than redesigning other portions of the project.

Is QII Required in California multifamily buildings

Does QII Apply to Multifamily Buildings?

Low-Rise Multifamily Requirements Include an Important Climate Zone 7 Exception

QII also appears in California’s multifamily Energy Code requirements, but the rules should not be copied directly from single-family projects without checking the building classification.

Under the current 2025 multifamily requirements, buildings up to three habitable stories have prescriptive QII requirements in Climate Zones 1 through 6 and 8 through 16.

Climate Zone 7 is an important exception for applicable low-rise multifamily QII requirements.

Why Is Climate Zone 7 Different for Low-Rise Multifamily?

California’s multifamily prescriptive requirements do not impose the same QII requirement in Climate Zone 7 that applies in the other listed climate zones.

This exception is specific to the applicable multifamily provisions and should not be confused with the single-family prescriptive rules.

Who Verifies Multifamily QII?

For applicable low-rise multifamily QII projects, an ECC Rater performs the required third-party field verification.

Current California multifamily compliance forms include separate QII documentation for:

  • Air-infiltration sealing at the framing stage
  • Insulation installation

Do Multifamily Additions Have QII Requirements?

California’s residential field-verification reference materials summarize QII as a prescriptive measure for applicable newly constructed buildings and additions greater than 700 square feet, subject to the low-rise multifamily Climate Zone 7 exception.

The actual building type, story count, climate zone, addition size, and selected compliance method should be confirmed before scheduling verification.

Does QII Apply to High-Rise Multifamily the Same Way?

No assumption should be made that every multifamily building uses the same residential QII procedure.

QII provisions specifically distinguish building categories and applicable low-rise multifamily conditions.

The project should be evaluated under the correct multifamily requirements.

Does QII Apply to Commercial Buildings?

The residential QII process should not automatically be applied to nonresidential construction.

Commercial and nonresidential buildings have their own envelope requirements, installation provisions, acceptance procedures, and documentation.

If a project contains residential and nonresidential occupancies, the applicable compliance requirements should be coordinated according to the actual building classification.

Why Building Classification Matters

The words “residential building” are not enough to determine the complete QII requirement.

The project may need to distinguish among:

  • Single-family residential
  • Low-rise multifamily
  • Other multifamily construction
  • Mixed-use construction
  • Nonresidential occupancy

AES can review the project documents and determine which compliance provisions apply.

Is QII Required in California construction inspections

When QII Is Required, Construction Scheduling Becomes Critical

Framing and Insulation Must Remain Accessible for Verification

QII is different from many paperwork-only compliance requirements because it depends on construction-stage verification.

The current California single-family forms include separate documentation for:

  • QII air-infiltration sealing at the framing stage
  • QII insulation installation

This means the project team needs to know about the requirement before drywall or other finishes conceal the relevant work.

When Should the ECC Rater Be Contacted?

Ideally, before the applicable construction work is concealed.

Scheduling should allow the rater to verify required conditions during the appropriate stages.

That can involve coordination among:

  • General contractor
  • Framing contractor
  • Insulation contractor
  • Energy consultant
  • ECC Rater
  • Project owner

What Happens at the Framing Stage?

The framing-stage portion addresses applicable air-infiltration sealing and air-barrier conditions.

The work must remain sufficiently visible for the applicable verification procedure.

What Happens at the Insulation Stage?

The rater can verify applicable insulation conditions such as:

  • Installed insulation type
  • Insulation levels
  • Gaps
  • Voids
  • Compression
  • Installation around obstructions
  • Hard-to-access cavities
  • Attic conditions
  • Other project-specific envelope details

What if Drywall Is Installed Before QII Verification?

That can create a significant compliance problem because the required conditions may no longer be visible.

The project team should contact the rater and energy consultant before assuming photographs or other documentation will automatically substitute for the required field verification.

Can Photographs Replace the Inspection?

Do not assume so.

QII verification must follow the applicable California procedures administered through the ECC Program.

The rater and applicable program requirements determine what verification is acceptable.

What if the Insulation Fails QII Verification?

The contractor normally needs to correct the identified condition so the applicable verification criteria can be satisfied.

Potential deficiencies can include:

  • Missing insulation
  • Gaps
  • Voids
  • Improper compression
  • Incomplete air barriers
  • Incorrect insulation levels
  • Installation that does not match the approved energy documentation

The goal is to correct the work while it remains accessible.

Does a Failed QII Inspection Mean the Permit Is Permanently Lost?

No.

A failed verification item means the applicable deficiency needs to be resolved.

The project should correct the work and complete the required compliance process.

Is QII Required in California current ECC verification

Current California Projects Use the ECC Program

Older Projects May Still Show HERS Terminology

The 2025 Energy Code changed the terminology used for Energy Code field verification and diagnostic testing.

The California Energy Commission’s Energy Code Compliance Program replaces the field-verification portion of the former HERS Program for Energy Code compliance.

Current terminology includes:

  • ECC Program
  • ECC Provider
  • ECC Rater
  • Field Verification and Diagnostic Testing

Older documents can still contain:

  • HERS Provider
  • HERS Rater
  • HERS verification

When Did the ECC Change Take Effect?

The change took effect with the 2025 Energy Code on January 1, 2026.

The applicable Energy Code version is generally tied to the permit application date.

What if My Project Uses the 2022 Energy Code?

Projects governed by an earlier Energy Code can continue using the compliance terminology and forms associated with that code cycle.

A 2022-code project may therefore continue to display HERS terminology even though current 2025-code documentation uses ECC terminology.

Should Old QII Documents Be Converted to New Forms?

Not simply because the calendar year changed.

First determine which Energy Code version governs the permit.

For additional guidance, review Which Title 24 Energy Code Version Do I Need.

What Documents Show Whether QII Is Required?

The project’s Certificate of Compliance is one of the most important documents to review.

It identifies applicable field-verification measures associated with the compliance design.

Current 2025 single-family QII forms include:

  • CF2R-ENV-21-H QII Air Infiltration Sealing – Framing Stage
  • CF2R-ENV-22-H QII Insulation Installation
  • CF3R-ENV-21-H QII Air Infiltration Sealing – Framing Stage
  • CF3R-ENV-22-H QII Insulation Installation

The California Energy Commission publishes these forms as part of the current 2025 single-family Energy Code compliance documents.

What Is the Difference Between CF2R and CF3R?

In the current single-family documentation system, CF2R forms document applicable installation information while CF3R forms document required verification.

Both can be part of demonstrating that a QII measure was properly installed and verified.

Does the Title 24 Report Replace the QII Verification Forms?

No.

The energy report identifies the energy-compliance design.

Required field-verification documentation establishes that applicable measures were installed and verified during construction.

They serve related but different purposes.

Is QII Required in California Title 24 assistance

Find Out Whether Your California Project Requires QII

Call (626) 365-1518 | Alternative Energy Systems

The safest way to answer Is QII Required in California for a specific project is to review the actual Title 24 documentation.

Useful information can include:

  • Current construction plans
  • Project type
  • Addition square footage when applicable
  • Energy Code version
  • Certificate of Compliance
  • Title 24 calculations
  • Insulation specifications
  • Existing HERS or ECC documents
  • Building-department correction notices

What if QII Is Already Listed on My Report?

Do not ignore the requirement.

The project team should determine which verification stages apply and schedule them before the relevant construction is concealed.

What if I Do Not Want QII?

Ask for a compliance review before construction proceeds.

Depending on the project, the performance approach may allow the design to demonstrate compliance without QII, but the software will account for reduced insulation effectiveness and other efficiency measures may be needed.

Can AES Determine Whether QII Can Be Removed?

AES can review the energy analysis and determine whether an alternate compliant design can be prepared.

That does not guarantee QII can be removed from every project.

The available options depend on:

  • Project design
  • Envelope performance
  • HVAC efficiency
  • Windows
  • Roof design
  • Other available efficiency measures

What if the Building Department Asks About QII?

Send AES the complete correction notice together with the current plans and energy documentation.

The issue may involve:

  • Missing forms
  • Missing field verification
  • Plan notes
  • Insulation specifications
  • A mismatch between the plans and energy report
  • An outdated code-cycle form

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides professional Title 24 calculations, energy-compliance documentation, revisions, and energy-related plan-check support throughout California.

AES brings more than 30 years of California energy-compliance experience to:

  • New homes
  • ADUs
  • Garage conversions
  • Additions
  • Residential remodels
  • Multifamily projects
  • Mixed-use projects
  • Envelope compliance
  • Projects involving QII
  • Energy-related plan-check corrections

AES prepares the energy-analysis side of the project and can identify required field-verification measures. Third-party verification remains a separate rater function unless the project agreement specifically states otherwise.

Learn more through the About Us page, review company background on the clients page, or explore Title 24 energy compliance.

Frequently Asked Questions: Is QII Required in California?

Is QII Required in California?

QII is a prescriptive requirement for many residential projects, including newly constructed single-family buildings and additions greater than 700 square feet under the 2025 prescriptive path. It is not universally required for every California permit.

Is QII required for every new single-family home?

Under the 2025 single-family prescriptive compliance path, QII is required for newly constructed buildings in all California climate zones.

Is QII a mandatory measure that can never be traded off?

No. The California Energy Commission states that QII is not a mandatory measure under the performance approach. It can be traded off with other efficiency measures.

What happens if a performance project does not use QII?

The compliance software reduces the modeled effectiveness of applicable insulation in the proposed design, so the project needs sufficient energy performance elsewhere to comply.

Is QII required for an addition over 700 square feet?

Under the applicable single-family prescriptive provisions, QII applies to additions greater than 700 square feet.

Is QII required for an addition of 700 square feet or less?

There is an applicable prescriptive exception for additions at or below 700 square feet. QII can still be used for performance credit, in which case verification is required.

Is QII required for an ADU addition under 700 square feet?

The California Energy Commission confirms that the prescriptive QII requirement does not apply to an ADU addition of 700 square feet or less. If QII is modeled for performance credit, verification is still required.

Is QII required for a detached ADU?

A newly constructed detached ADU is generally treated as new residential construction for applicable Energy Code requirements. Its compliance documents should be reviewed to confirm the required measures.

Is QII required for a garage conversion?

Not automatically. The answer depends on how the conversion is classified under the Energy Code and which compliance method is used.

Is QII required for a remodel?

Not every remodel requires formal QII verification. The project scope, code provisions, and compliance method determine whether QII applies.

Is QII required in every California climate zone?

For newly constructed single-family buildings under the prescriptive path, QII applies in all climate zones. Low-rise multifamily has a Climate Zone 7 exception under the applicable current provisions.

Is QII required for low-rise multifamily buildings?

Current prescriptive requirements apply QII to applicable multifamily buildings up to three habitable stories in Climate Zones 1 through 6 and 8 through 16. Climate Zone 7 is excluded from that prescriptive requirement.

Is QII required for commercial buildings?

The residential QII verification process should not automatically be applied to nonresidential projects. Commercial buildings have separate envelope and compliance requirements.

Who verifies QII?

For current 2025 Energy Code projects, an appropriately qualified ECC Rater performs required third-party field verification.

Is a HERS Rater still used?

Current 2025-code documentation uses ECC terminology. Earlier code-cycle documents can continue to use HERS terminology.

When did California change to ECC?

The Energy Code Compliance Program replaced the Energy Code field-verification portion of HERS with the 2025 Energy Code effective January 1, 2026.

Does QII require more than one inspection?

Applicable QII documentation includes framing-stage air-sealing verification and insulation-stage verification.

Can QII be inspected after drywall?

Required QII conditions should be verified while they remain accessible. Concealing the work before verification can create compliance problems.

What if QII fails?

The applicable installation deficiency should be corrected so the required verification can be completed.

Can QII be removed from the Title 24 report?

Potentially under a compliant revised performance design, but removing it can affect the energy model and may require other efficiency improvements.

Can photographs replace an ECC Rater inspection?

Do not assume they can. Required verification must follow the applicable California procedures and ECC Program requirements.

Does QII guarantee permit approval?

No. QII is one part of Energy Code compliance, and the complete project remains subject to all other applicable permit requirements.

How do I know whether my project has QII?

Review the project’s Certificate of Compliance and Title 24 energy report for listed field-verification measures.

What should I send AES?

Send the current plans, Certificate of Compliance, Title 24 calculations, insulation specifications, code-cycle information, existing HERS or ECC documents, and any building-department corrections.

How do I get help determining whether QII applies?

Call Alternative Energy Systems at (626) 365-1518, email info@title24energy.com, or use the contact page.

When service and payment have already been arranged, payment can be completed through the AES payment page.

What Is QII HERS Verification?

What Is QII HERS Verification

What Is QII HERS Verification?

Call (626) 365-1518 | Alternative Energy Systems

What Is QII HERS Verification is an important question when a California Title 24 energy report identifies Quality Insulation Installation as a compliance measure that must be verified during construction.
QII stands for Quality Insulation Installation.
The purpose of QII is not simply to confirm that insulation exists inside the building. It verifies that the insulation and associated air barriers are installed in a manner consistent with the California Energy Code, the approved energy documentation, applicable installation procedures, and the insulation manufacturer’s instructions.
QII can involve verification of:

  • Air-barrier installation
  • Air-infiltration sealing
  • Wall insulation
  • Ceiling insulation
  • Roof-deck insulation
  • Raised-floor insulation
  • Insulation around plumbing and wiring
  • Insulation around electrical boxes
  • Hard-to-access framing cavities
  • Window and door headers when applicable
  • Attic conditions
  • Kneewalls and skylight shafts
  • Other applicable portions of the thermal envelope

The inspection occurs during construction because many of these conditions become impossible or difficult to see after drywall, interior finishes, or other materials conceal the framing and insulation.
For projects using the current 2025 California Energy Code, the terminology has changed.
Older California projects and forms commonly referred to this third-party process as HERS verification. Beginning with the 2025 Energy Code, California moved Energy Code field verification and diagnostic testing into the Energy Code Compliance Program, commonly abbreviated ECC.
That means a current 2025-code project will generally refer to an ECC Rater rather than a HERS Rater for this compliance verification.
The older phrase remains useful because many homeowners, builders, designers, contractors, existing permit files, and internet searches still refer to QII HERS Verification.
For general background on residential energy-rating terminology, review Home Energy Rating on Wikipedia. California’s Energy Code Compliance Program is a separate state compliance system, so the California requirements should always be confirmed through current California Energy Commission documentation.
Alternative Energy Systems brings more than 30 years of California energy-compliance experience to residential, multifamily, mixed-use, and commercial projects.
AES can prepare the applicable Title 24 analysis, identify QII when it appears as a required compliance measure, and help coordinate the energy documentation with the construction plans. Required field verification is performed separately by the appropriately qualified third-party rater.
Call (626) 365-1518 if QII appears on your energy report or permit documents and you need help understanding what the project requires.

What Does QII Mean?

QII means Quality Insulation Installation.
The concept recognizes that insulation performance depends on more than the R-value printed on the product.
Two walls can contain insulation labeled with the same nominal R-value while performing differently if one installation contains:

  • Large gaps
  • Voids
  • Compression
  • Poor fitting around pipes
  • Poor fitting around electrical wiring
  • Missing insulation behind obstructions
  • Disconnected air barriers

QII addresses the quality of the complete installation rather than assuming that purchasing insulation with the correct label is enough.

Why Does Insulation Installation Quality Matter?

Insulation is intended to reduce heat transfer through the building envelope.
That envelope can include:

  • Exterior walls
  • Ceilings
  • Roofs
  • Floors over unconditioned spaces
  • Kneewalls
  • Other boundaries between conditioned and unconditioned space

Gaps and compressed insulation can create portions of an assembly that do not perform the way the energy analysis assumed.
Air leakage can also bypass insulation and reduce the effectiveness of the thermal envelope.
QII therefore looks at both insulation installation and applicable air-barrier conditions.

QII Is Not Just an Insulation R-Value Check

A QII verification does not simply involve locating an insulation label and confirming that it says R-13, R-15, R-21, R-30, or another value.
The installation itself matters.
Depending on the assembly, the verification can address whether insulation:

  • Fills the intended cavity
  • Remains in contact with required air barriers
  • Fits around obstructions
  • Avoids significant gaps and voids
  • Avoids improper compression
  • Matches the approved Certificate of Compliance
  • Was installed according to manufacturer instructions

The exact requirements depend on the construction assembly and applicable QII procedure.

QII Is Also an Air-Sealing Process

Quality insulation depends on controlling unwanted air movement through the building envelope.
The QII process therefore includes an air-infiltration-sealing stage before the insulation installation is complete.
Potential air-leakage locations can include:

  • Framing intersections
  • Utility penetrations
  • Plumbing penetrations
  • Electrical penetrations
  • Floor transitions
  • Ceiling transitions
  • Garage interfaces
  • Attic boundaries
  • Other envelope penetrations

The details vary according to the building.

What Is QII HERS Verification framing stage

QII Verification Happens During More Than One Construction Stage

Framing and Air Sealing Must Be Reviewed Before They Are Concealed

One of the most important things to understand about QII is timing.
The verification cannot simply be postponed until construction is completely finished.
California provides separate QII documentation for:

  • Air-infiltration sealing at the framing stage
  • Insulation installation

These stages exist because important construction details become concealed as the project progresses.

What Is the QII Framing-Stage Verification?

The framing-stage portion focuses on the building’s air-barrier system and preparation for insulation.
This stage occurs early enough for applicable envelope conditions to remain visible.
The current single-family forms identify QII air-infiltration sealing as a distinct framing-stage verification.
That can involve review of areas such as:

  • Walls adjacent to unconditioned space
  • Raised floors
  • Ceiling air barriers
  • Unvented attic boundaries
  • Garage interfaces
  • Cantilevered floors
  • Attached porches
  • Other applicable envelope assemblies

Why Must the Framing Stage Happen Before Insulation?

Some sealing and air-barrier conditions need to be visible before cavities are filled.
If insulation covers the framing before the applicable inspection occurs, the rater may not be able to verify the required conditions.
That can create avoidable construction delays or corrective work.
Builders and insulation contractors should therefore identify a QII requirement before insulation work begins.

What Is Checked During Air-Sealing Verification?

The specific checklist depends on the building, but the objective is to verify that applicable boundaries between conditioned and unconditioned areas have been prepared properly.
The rater is looking for construction that corresponds to the QII requirements rather than simply checking whether caulk or foam appears somewhere in the building.

What Happens After the Framing-Stage Verification?

Once applicable framing and air-sealing requirements have been addressed, insulation installation can proceed.
That does not complete QII.
A separate insulation-stage verification is still associated with the QII process when required.

Should the Insulation Contractor Know QII Is Required?

Yes.
The insulation installer needs to understand that the project is being built using QII assumptions.
That can affect:

  • Installation quality
  • Scheduling
  • Product documentation
  • Access for verification
  • Correction of deficiencies

Finding out that QII is required after the insulation has already been covered is a preventable coordination problem.

Where Is QII Shown in the Title 24 Documentation?

When QII is part of the compliance design, it should be reflected in the applicable energy documentation.
Required field-verification measures are identified through the project’s compliance documents.
The contractor should review those documents before beginning the affected work.

What Is QII HERS Verification insulation inspection

What Does the QII Insulation Verification Check?

The Installed Insulation Must Match the Approved Energy Design

The insulation-stage verification occurs while the insulation remains accessible for inspection.
The current California QII verification documentation addresses multiple envelope assemblies and installation conditions.

Insulation Must Match the Certificate of Compliance

The insulation installed in the building should meet or exceed the applicable levels identified in the project’s Certificate of Compliance.
The field installation and energy calculation should represent the same building.
If the report identifies one envelope assembly but a different assembly is installed, the discrepancy needs to be resolved.

Gaps and Voids Matter

Insulation should fit the cavity and applicable air barriers as required by the QII procedures.
For applicable batt and loose-fill wall installations, current verification criteria address proper contact and the absence of unacceptable:

  • Gaps
  • Voids
  • Compression

A partially insulated cavity should not automatically be treated as equivalent to a correctly filled cavity.

Insulation Around Electrical Boxes Matters

Electrical boxes interrupt wall cavities.
Insulation needs to fit around these obstructions according to the applicable installation criteria rather than leaving substantial uninsulated spaces.
The same principle applies to other penetrations.

Insulation Around Plumbing and Wiring Matters

Pipes and wiring can make insulation installation more difficult.
The insulation must be fitted around those obstructions so the assembly performs as intended.
Forcing a full batt into a complicated cavity without properly fitting it around obstructions can create compression and voids.

Hard-to-Reach Wall Cavities Matter

Certain framing conditions can become inaccessible later.
Examples can include:

  • Wall intersections
  • Corner channels
  • Other enclosed framing locations

Current QII criteria specifically address insulation in hard-to-access cavities before exterior finishes or other construction makes those locations inaccessible.

Insulation Behind Tubs and Showers Can Matter

When tubs, showers, fireplaces, stairwells, or similar assemblies are located against exterior walls, insulation and air-barrier conditions can become difficult to correct after those features are installed.
QII procedures therefore address applicable insulation behind these areas.

Window and Door Headers Can Matter

Applicable QII criteria include insulation conditions for certain single-member window and door headers.
The requirement depends on the framing assembly.
This is another example of why QII is more detailed than a simple wall-cavity inspection.

Attic Insulation Is Also Part of QII

Applicable attic conditions can include:

  • Insulation contact with the ceiling air barrier
  • Attic access insulation
  • Insulation dams
  • Eave ventilation
  • Loose-fill insulation depth
  • Other applicable roof or ceiling conditions

The exact checklist varies according to the attic design.

Loose-Fill Insulation Has Additional Verification Details

Current California QII documentation includes procedures for checking loose-fill insulation depth and density.
Manufacturer coverage information can be important.
The current single-family QII form also requires product labels or specification information to be available to the rater.

What Is QII HERS Verification HERS versus ECC

Is It Still Called HERS Verification in 2026?

The 2025 Energy Code Uses ECC Rater Terminology for Current Projects

This terminology change is important.
For older California Energy Code cycles, field verification and diagnostic testing were performed through the Home Energy Rating System compliance structure.
Those projects use terminology such as:

  • HERS Provider
  • HERS Rater
  • HERS verification

California reorganized this process for the 2025 Energy Code.
Beginning January 1, 2026, the field-verification and diagnostic-testing portion of Energy Code compliance moved into the Energy Code Compliance Program.
Current terminology includes:

  • ECC Provider
  • ECC Rater
  • Field Verification and Diagnostic Testing

For official information about this change, review the California Energy Commission Energy Code Compliance Program.

Why Do People Still Search for QII HERS Verification?

There are several practical reasons.
Older permit files still contain HERS terminology.
Architects, contractors, consultants, inspectors, and property owners have used the term for many years.
Search engines also contain years of information based on older code cycles.
A project submitted under the 2022 Energy Code may still correctly contain HERS terminology.
A new project using the 2025 Energy Code should use the current ECC terminology where the current compliance documents require it.

Does the Terminology Change Alter the Purpose of QII?

The program terminology changed, but the basic reason for third-party field verification remains straightforward.
Certain Energy Code measures depend on real installation conditions that cannot be established from plans alone.
Field verification confirms that applicable measures were actually installed according to the required procedures.

What Happens to an Older 2022 Project?

An older project established under the 2022 Energy Code can continue to use the HERS terminology and documentation associated with that code cycle.
Do not automatically convert old forms to 2025 ECC forms simply because the calendar is now 2026.
The applicable code cycle should be established first.
For more information, review Which Title 24 Energy Code Version Do I Need.

What About a New 2026 Permit Application?

An applicable new permit application filed on or after January 1, 2026 uses the 2025 California Energy Code.
When that project requires field verification, current ECC procedures and documentation apply.
The project team should use the forms associated with the correct code cycle.

Can the Building Department Perform the ECC Verification?

Building-department inspection and required third-party Energy Code verification are different functions.
When a compliance measure requires verification by an ECC Rater, ordinary building inspection should not be assumed to replace that requirement.
The applicable registered compliance documentation needs to be completed through the required process.

Does AES Perform the Third-Party Verification?

Alternative Energy Systems prepares energy-compliance calculations and documentation and can identify QII or other verification measures associated with a project.
Required third-party field verification is a separate construction-stage service performed by an appropriately qualified rater.
Do not assume the preparation of the Title 24 report automatically includes every third-party field-verification service.
The project agreement should identify the scope of services being provided.

What Is QII HERS Verification for Title 24 compliance

When Is QII Required for a Title 24 Project?

The Certificate of Compliance Determines Whether QII Is Part of the Design

QII should not be described as a universal requirement for every California permit.
Whether it applies depends on:

  • Building type
  • Project scope
  • Code cycle
  • Compliance method
  • Energy model
  • Measures selected for compliance

Under the current 2025 Energy Code, when performance compliance requires field verification of QII, the building insulation system must be verified using the applicable California procedures.

Is QII Required on Every New Home?

Do not assume that every project automatically uses the same QII compliance measure.
New single-family buildings have field-verification requirements under the current Energy Code, but the individual measures required for a particular project are identified in the project’s Certificate of Compliance.
QII should be scheduled when the compliance documentation identifies it.

Can QII Be Used as a Performance Compliance Measure?

Yes.
The current 2025 Energy Code specifically addresses QII when performance compliance requires field verification of the measure.
When QII is modeled for compliance, the field installation must support the assumptions used in the performance analysis.

Does QII Apply to the Whole New Building?

Current 2025 single-family QII instructions state that QII applies to the entire building envelope for new construction when the measure is used.
That can include applicable:

  • Roof and ceiling assemblies
  • Walls
  • Floors

The detailed requirements depend on each assembly.

Can an Addition Use QII?

QII treatment for additions is more specific.
Under current 2025 single-family instructions, compliance credit for applicable addition or alteration situations is associated with the existing-plus-addition-plus-alteration performance approach, with the credit applying to qualifying new surfaces in the new zone.
The actual project should be reviewed before assuming QII credit is available.

Does a Small Remodel Automatically Need QII?

No.
The fact that insulation is being installed does not by itself establish that formal QII field verification is required.
The project’s compliance documentation and applicable code provisions determine whether the QII verification measure applies.

What About ADUs?

A new detached ADU can be treated as new residential construction under the applicable Energy Code provisions.
If its compliance documentation identifies QII field verification, the construction needs to be coordinated accordingly.
Attached ADUs and conversions can involve different conditions.
For more information, review ADU Title 24.

What About Multifamily Projects?

Current California compliance documents also include QII installation and verification forms for applicable low-rise multifamily work.
Multifamily projects should be evaluated under the correct multifamily requirements rather than assuming that every single-family procedure applies unchanged.

What About Commercial Buildings?

QII HERS terminology is primarily associated with residential Energy Code procedures.
Commercial and nonresidential buildings have their own envelope installation, acceptance, and compliance requirements.
Do not automatically apply residential QII forms to a nonresidential building.

What Is QII HERS Verification pass fail correction process

What Happens if the Insulation Does Not Pass QII Verification?

Corrections Should Be Made While the Work Is Still Accessible

The current QII verification forms provide for a verification status that can indicate whether applicable requirements pass or fail.
When deficiencies are found, correction notes can identify what needs attention.
The practical objective is to correct the installation before it becomes concealed.

What Can Cause a QII Verification Problem?

Potential issues can include:

  • Missing insulation
  • Gaps
  • Voids
  • Excessive compression
  • Insulation that does not fit around wiring
  • Insulation that does not fit around plumbing
  • Missing insulation in difficult framing locations
  • Incorrect attic conditions
  • Missing or incomplete air barriers
  • Insulation that does not match the approved documentation

The actual correction depends on the assembly.

Does Failing an Inspection Mean the Entire Project Fails?

A failed verification item means the applicable requirement needs to be addressed.
It should not automatically be interpreted as permanent failure of the entire building project.
The normal objective is to identify the deficiency, correct the condition, and complete the required verification process.

Can the Contractor Fix the Problem?

Applicable installation deficiencies can generally be corrected while the work remains accessible.
The contractor or insulation installer should coordinate with the rater regarding the items identified for correction.
The rater determines whether the applicable verification criteria have been satisfied.

What if Drywall Was Installed Too Soon?

This can create a serious coordination problem because insulation and air-barrier conditions may no longer be visible.
The appropriate response depends on what needs to be verified and what documentation is available.
The project team should contact the rater before assuming that photographs, statements, or other records will replace an inspection.
Do not conceal QII work until the required verification stages have been coordinated.

Can Photographs Replace the QII Inspection?

Do not assume so.
Required field verification follows specific California procedures.
Whether any alternative documentation is acceptable is determined by the applicable program requirements and rater procedures, not simply by whether photographs were taken.

Can the Title 24 Consultant Waive QII?

Not simply because construction has already progressed.
If QII is part of the approved compliance design, removing the measure can affect the energy calculation.
The project may need:

  • A revised analysis
  • Different compliance measures
  • Updated forms
  • Plan revisions

Whether an alternate design complies must be determined through the applicable Energy Code process.

Can QII Be Removed From the Energy Model?

Potentially, if a revised compliant design is available.
Removing QII from a performance model can change the modeled energy performance of the building.
Other efficiency measures may need to compensate.
The calculation should be revised before assuming the project remains compliant.

Should QII Be Removed Just to Avoid Verification?

That is a design and compliance decision rather than simply a scheduling decision.
The project team should evaluate:

  • Energy performance
  • Construction cost
  • Alternative measures
  • Revision requirements
  • Project schedule

before changing an approved compliance strategy.

Does Passing QII Guarantee the Entire Permit Will Be Approved?

No.
QII verification addresses applicable insulation and envelope requirements.
The complete permit remains subject to all other applicable:

  • Energy Code requirements
  • Building Code requirements
  • Mechanical requirements
  • Electrical requirements
  • Plumbing requirements
  • CALGreen requirements
  • Local plan-review requirements

QII is one part of the overall compliance process.

What Is QII HERS Verification help from Alternative Energy Systems

Need Help Understanding QII on Your Title 24 Report?

Call (626) 365-1518 | Alternative Energy Systems

If your Title 24 report identifies QII, review the requirement before framing, insulation, and drywall schedules are finalized.
Alternative Energy Systems can review the energy-compliance documentation and help identify:

  • Whether QII appears in the compliance design
  • Which code cycle the project uses
  • Whether the project documentation uses HERS or ECC terminology
  • Which envelope assemblies are represented in the calculation
  • Whether design changes may require revised calculations

What Should I Send AES?

Useful information can include:

  • Current construction plans
  • Existing Title 24 calculations
  • Certificate of Compliance
  • Insulation specifications
  • Wall and roof details
  • Existing HERS or ECC documentation
  • Building-department correction notices
  • A description of current construction progress

For a broader project intake guide, review what AES will need from you.

What if My Existing Report Says HERS?

First determine the applicable Energy Code version.
A 2022-code project can legitimately contain HERS terminology.
A current 2025-code project uses the new ECC compliance terminology.
Do not replace forms simply because the names changed without confirming the project’s code cycle.

What if My Current 2025 Report Says QII?

The project team should identify the required ECC field-verification stages and coordinate them before the relevant work is concealed.
Current California single-family compliance documents include:

  • CF2R-ENV-21-H QII Air Infiltration Sealing – Framing Stage
  • CF2R-ENV-22-H QII Insulation Installation
  • CF3R-ENV-21-H QII Air Infiltration Sealing – Framing Stage
  • CF3R-ENV-22-H QII Insulation Installation

The Certificate of Installation and Certificate of Verification serve different roles in the compliance process.

What Is the Difference Between CF2R and CF3R QII Forms?

For current single-family compliance documentation:

  • CF2R forms are Certificates of Installation
  • CF3R forms are Certificates of Verification

The installation documentation and third-party verification documentation work together to demonstrate the applicable measure.

Who Coordinates the Rater?

Project responsibility can vary according to the contract and construction team.
The builder, owner, contractor, or another responsible project participant should make sure the required verification is scheduled at the correct construction stage.
Do not assume the building department or energy consultant automatically schedules every required third-party inspection.

When Should the Rater Be Contacted?

Before applicable QII work becomes concealed.
Ideally, the requirement is identified early enough to coordinate:

  • Framing-stage verification
  • Air sealing
  • Insulation installation
  • Insulation-stage verification
  • Drywall scheduling

Early coordination can prevent the project from reaching a stage where required conditions can no longer be inspected easily.

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides professional Title 24 calculations, compliance documentation, revisions, and energy-related plan-check support throughout California.
AES brings more than 30 years of California energy-compliance experience to:

  • New homes
  • ADUs
  • Garage conversions
  • Additions
  • Residential remodels
  • Multifamily projects
  • Mixed-use projects
  • Envelope compliance
  • Projects involving QII requirements
  • Energy-related plan-check corrections

AES prepares and coordinates the energy-analysis side of the project while required third-party field verification remains a separate rater function unless a project agreement expressly states otherwise.
Learn more through the About Us page, review company background on the clients page, or explore Title 24 energy compliance.

Frequently Asked Questions: What Is QII HERS Verification?

What Is QII HERS Verification?

QII HERS Verification is the commonly used older term for third-party field verification of Quality Insulation Installation under California Title 24. For 2025-code projects, current California terminology uses the Energy Code Compliance Program and ECC Raters instead of HERS Raters for Energy Code field verification.

What does QII stand for?

QII stands for Quality Insulation Installation.

What is the purpose of QII?

QII verifies applicable insulation installation and air-barrier conditions rather than assuming that nominal insulation R-value alone represents the completed building envelope.

Is QII just an insulation inspection?

No. QII also includes applicable air-infiltration-sealing and air-barrier requirements.

Is QII still called HERS verification?

Older code cycles use HERS terminology. Current 2025 Energy Code compliance uses ECC terminology for field verification and diagnostic testing.

When did California change from HERS to ECC for Energy Code verification?

The change applies with the 2025 Energy Code, which became effective January 1, 2026.

Does every new home require QII?

Do not assume that QII is an identical requirement on every project. The project’s Certificate of Compliance identifies the field-verification measures required for that design.

Can QII be used with performance compliance?

Yes. The 2025 Energy Code specifically requires field verification when QII is used as a verified performance-compliance measure.

Does QII apply to the entire building?

For applicable 2025 new-construction QII projects, current single-family instructions state that QII applies to the building envelope, including applicable roof or ceiling, wall, and floor assemblies.

Can an addition use QII credit?

Current 2025 instructions provide specific conditions for QII credit in applicable existing-plus-addition-plus-alteration performance projects. The actual project should be reviewed before assuming credit is available.

What happens at the framing-stage QII inspection?

Applicable air-barrier and air-infiltration-sealing conditions are verified before insulation conceals the framing.

What happens at the insulation-stage inspection?

The rater verifies applicable insulation materials and installation conditions while they remain accessible.

Does the rater check for insulation gaps?

Yes. Applicable QII criteria address gaps, voids, compression, and proper fitting of insulation.

Does insulation need to fit around electrical boxes?

Applicable QII criteria require insulation to fit around obstructions such as electrical boxes, plumbing, and wiring without improper gaps, voids, or compression.

Does attic insulation get checked?

Applicable QII procedures include attic, ceiling, roof-deck, access, ventilation, and insulation conditions according to the project configuration.

Does loose-fill insulation get checked?

Yes. Current QII procedures include applicable depth and density verification for loose-fill insulation.

What if the insulation fails verification?

The deficient condition should be corrected and the required verification process completed before the affected work is concealed whenever possible.

Can drywall be installed before QII verification?

Required inspection stages should be completed before drywall or other construction conceals the conditions that must be verified.

Can photographs replace the field inspection?

Do not assume they can. Required verification must follow the applicable California procedures and rater requirements.

Can the Title 24 consultant remove QII after construction starts?

Not automatically. If QII is part of the approved compliance model, removing it can require a revised energy analysis and potentially other efficiency measures.

Does passing QII guarantee permit approval?

No. QII verification addresses one portion of Energy Code compliance. The complete project remains subject to all applicable permit requirements.

What is a CF2R QII form?

For current single-family compliance, applicable CF2R QII forms document installation requirements.

What is a CF3R QII form?

Applicable CF3R QII forms are Certificates of Verification documenting required third-party field verification.

Who performs current 2025 QII verification?

Required third-party verification is performed by an appropriately qualified ECC Rater under the current Energy Code Compliance Program.

What if my project was permitted under the 2022 Energy Code?

Older 2022 projects continue to use the HERS terminology and procedures associated with that code cycle.

What if my permit application is new in 2026?

Applicable new permit applications filed on or after January 1, 2026 use the 2025 Energy Code and current ECC terminology.

How do I know if my project requires QII?

Review the Certificate of Compliance and energy report. AES can also review the Title 24 documentation and explain which field-verification measures appear in the design.

What should I send AES?

Send the current plans, Title 24 report, Certificate of Compliance, insulation and envelope information, available HERS or ECC documents, and any building-department correction comments.

How do I get help understanding QII?

Call Alternative Energy Systems at (626) 365-1518, email info@title24energy.com, or use the contact page.

What Is an Energy Recovery Ventilator?

What Is an Energy Recovery Ventilator

What Is an Energy Recovery Ventilator?

Call (626) 365-1518 | Alternative Energy Systems

What Is an Energy Recovery Ventilator is an increasingly important question as California buildings become tighter, more energy efficient, and more dependent on planned mechanical ventilation instead of uncontrolled air leakage.

An energy recovery ventilator, commonly abbreviated as ERV, is a mechanical ventilation system that brings outdoor air into a building while exhausting indoor air.

What makes the system different from a basic exhaust fan or supply fan is the energy-recovery core located between the two air streams.

As outgoing indoor air and incoming outdoor air pass through separate pathways in the unit, the ERV can transfer a portion of the energy between them before the outdoor air enters the occupied space.

Depending on the equipment, that transfer can involve:

  • Sensible heat associated with air temperature
  • Latent energy associated with moisture

This allows the ventilation system to introduce outdoor air without throwing away as much of the heating or cooling energy already used to condition the indoor air.

An ERV can include:

  • An outdoor-air intake
  • An indoor exhaust-air path
  • A heat-and-moisture transfer core or wheel
  • Supply and exhaust fans
  • Air filters
  • Ductwork
  • Controls
  • Outdoor and indoor air connections

The system is commonly used as a form of balanced mechanical ventilation.

For general background on the technology, review the energy recovery ventilation information on Wikipedia.

Alternative Energy Systems provides professional Title 24 calculations and energy-compliance documentation for residential, multifamily, mixed-use, and commercial projects throughout California.

If your plans include an ERV, HRV, balanced ventilation system, or other mechanical ventilation equipment, call (626) 365-1518 to have the system reviewed as part of the applicable energy-compliance design.

Why Buildings Need Mechanical Ventilation

Buildings need outdoor air.

Historically, some buildings received substantial outdoor air through gaps and leakage around:

  • Windows
  • Doors
  • Walls
  • Roofs
  • Utility penetrations

Modern energy-efficient construction is generally more airtight.

That reduces uncontrolled air leakage, but it also means ventilation needs to be planned intentionally.

Mechanical ventilation can provide a controlled path for bringing outdoor air into the building while removing indoor air.

The objective is not simply to make a building leakier.

It is to provide outdoor air at a known rate through a designed ventilation system.

What Makes an ERV Different From a Basic Ventilation Fan?

A basic exhaust fan removes indoor air.

A basic supply fan brings outdoor air inside.

An ERV does both while recovering part of the energy that would otherwise leave with the exhaust air.

Consider an air-conditioned building on a hot day.

The indoor exhaust air may be cooler and drier than the outdoor air.

Instead of exhausting that conditioned air directly outdoors without recovering anything from it, an ERV passes the outgoing and incoming air streams through an energy-recovery component.

The incoming air can then be partially preconditioned before it reaches the occupied space or HVAC system.

During cooler weather, the process can work in the opposite direction.

Does the Exhaust Air Mix With the Incoming Air?

The supply and exhaust air streams are designed as separate air paths.

Energy is transferred across or through the recovery medium.

Depending on the ERV technology, a limited amount of air transfer or leakage can occur, which is one reason equipment ratings, installation, pressure relationships, and application matter.

An ERV should not simply be described as mixing stale indoor air with fresh outdoor air.

Its purpose is to exchange energy between separate ventilation air streams.

What Does the Recovery Core Do?

The recovery core is the central component of many ERV systems.

As indoor exhaust air and outdoor supply air pass through the equipment, the core allows energy to move between those air streams.

In an ERV designed for moisture transfer, the core can also allow controlled transfer of water vapor.

Different manufacturers use different recovery technologies.

These can include:

  • Fixed-plate enthalpy cores
  • Membrane-based cores
  • Rotary energy-recovery wheels
  • Other approved heat-and-moisture recovery designs

The performance of these technologies is not identical.

Equipment specifications should therefore be reviewed rather than assuming every ERV has the same recovery efficiency.

What Is Sensible Heat Recovery?

Sensible heat relates to air temperature.

If outdoor air is much warmer or colder than indoor air, the ERV can transfer some thermal energy between the two air streams.

This can reduce the temperature difference the HVAC system must handle after ventilation air enters the building.

What Is Latent Energy Recovery?

Latent energy relates to moisture in the air.

Many ERVs are designed to transfer some water vapor between the incoming and outgoing air streams.

This distinguishes an ERV from systems designed primarily for sensible heat recovery.

How much moisture transfer occurs depends on the equipment and operating conditions.

What Is an Energy Recovery Ventilator and how does it work

How an Energy Recovery Ventilator Works

Outdoor Air and Exhaust Air Pass Through Separate Recovery Paths

An ERV usually operates two air streams at the same time.

One side brings outdoor air toward the occupied building.

The other side removes indoor air.

The process can be understood as follows.

1. Outdoor Air Enters the ERV

Outdoor air enters through a dedicated intake.

The air normally passes through a filter before or as it enters the recovery section.

2. Indoor Air Is Exhausted

Indoor air is collected from appropriate exhaust locations and routed toward the ERV.

Those locations depend on the building and ventilation design.

3. The Two Air Streams Pass Through the Recovery Component

The incoming and outgoing air remain in separate pathways while energy is transferred between them.

4. Outdoor Air Is Supplied to the Building

The partially conditioned outdoor air is delivered to the occupied building or connected mechanical system.

5. Exhaust Air Leaves the Building

After passing through the recovery section, the exhaust air is discharged outdoors.

What Does Balanced Ventilation Mean?

A balanced ventilation system uses both mechanical supply and mechanical exhaust.

The system is designed so outdoor air entering the building and indoor air leaving the building are controlled together.

An ERV is commonly used in a balanced ventilation configuration.

Balanced ventilation can help designers manage building pressure more intentionally than an exhaust-only or supply-only strategy.

Is an ERV Part of the Heating and Air Conditioning System?

It can be integrated with HVAC equipment, but it is not the same thing as the primary heating or cooling system.

An ERV’s principal function is ventilation and energy recovery.

A furnace, air conditioner, or heat pump provides space conditioning.

Depending on the design, the ERV may:

  • Use dedicated ventilation ductwork
  • Connect to portions of the central air distribution system
  • Operate through a dedicated outdoor-air configuration
  • Serve one dwelling unit
  • Serve multiple spaces or units through a central system

The correct arrangement depends on the building.

Does an ERV Heat and Cool a House by Itself?

Generally, no.

An ERV can precondition incoming ventilation air, but it should not automatically be treated as a substitute for the building’s heating and cooling equipment.

Its energy-recovery function can reduce ventilation-related heating or cooling demand.

The primary HVAC system still needs to satisfy the applicable building loads.

Does an ERV Run All the Time?

Operation depends on the ventilation design and controls.

A system may operate:

  • Continuously
  • Intermittently according to a ventilation schedule
  • At multiple speeds
  • Under automatic controls

The installed controls should provide the ventilation airflow required by the approved design.

What Happens During Mild Weather?

There can be conditions when recovering heat from exhaust air is not useful.

Certain systems therefore include:

  • Recovery bypass
  • Free-cooling operation
  • Economizer-related controls

These features allow outdoor air to be used more directly when recovery would work against the desired indoor condition.

Applicable California requirements depend on building type and system configuration.

What Is Sensible Recovery Efficiency?

Sensible recovery efficiency is one measure used to describe how effectively an HRV or ERV recovers temperature-related energy.

California’s current Energy Code uses sensible recovery efficiency in certain ERV and HRV provisions.

The required value is project-specific and should not be assumed from the letters “ERV” alone.

What Is Fan Efficacy?

Energy recovery is only part of overall system performance.

The fans themselves consume electricity.

Fan efficacy expresses fan electrical power relative to airflow.

A ventilation system therefore should not be evaluated only according to how much energy its core recovers.

The energy required to move the air also matters.

What Is an Energy Recovery Ventilator compared with a heat recovery ventilator

Energy Recovery Ventilator vs. Heat Recovery Ventilator

Both Recover Heat, but Moisture Transfer Is the Important Difference

Energy recovery ventilators and heat recovery ventilators are closely related technologies.

Both use outgoing indoor air to recover energy that can be used to precondition incoming outdoor air.

The major distinction is the type of energy transfer.

What Does an HRV Recover?

A heat recovery ventilator primarily transfers sensible heat.

In other words, it exchanges temperature-related energy between the incoming and outgoing air streams.

Its recovery core is generally not intended to transfer substantial moisture between the two streams.

What Does an ERV Recover?

An energy recovery ventilator generally transfers both:

  • Sensible heat
  • Latent energy associated with moisture

That moisture-transfer capability can affect indoor humidity conditions and ventilation loads.

The extent of that transfer depends on equipment design and operating conditions.

Is an ERV Always Better Than an HRV?

No.

The right system depends on:

  • Climate
  • Building type
  • Indoor moisture conditions
  • Outdoor moisture conditions
  • Ventilation airflow
  • Mechanical design
  • Applicable Energy Code requirements

An ERV should not be selected simply because its name sounds more advanced.

The equipment should fit the building and compliance strategy.

Does an ERV Dehumidify the Building?

An ERV can transfer moisture and may reduce some moisture-related ventilation load under appropriate conditions.

However, it is not automatically a dedicated dehumidifier.

A building with significant humidity-control requirements may still need separate HVAC or dehumidification capacity.

Can an ERV Add Moisture During Cold Weather?

Depending on indoor and outdoor conditions, an ERV can retain a portion of moisture that would otherwise leave with the exhaust air.

That can help reduce excessive drying in some climates.

The actual effect varies with equipment performance, airflow, weather, occupancy, and indoor moisture generation.

Does an HRV Remove More Moisture?

An HRV does not intentionally transfer latent moisture back to the incoming air in the same way as an ERV.

That difference can make HRV and ERV systems behave differently in various climates.

System selection should be based on actual project needs.

Can the Terms ERV and HRV Be Used Interchangeably?

They should not automatically be treated as identical.

Both are heat-recovery ventilation technologies, but an ERV’s ability to transfer latent energy distinguishes it from a sensible-only HRV.

The product specified in the Title 24 calculations should match the equipment intended for installation.

What Is an Energy Recovery Ventilator for indoor air and mechanical ventilation

What Does an ERV Do for Indoor Ventilation?

Filtered Outdoor Air Is Supplied While Indoor Air Is Mechanically Exhausted

An ERV can provide controlled whole-building ventilation.

That can help reduce reliance on random air leakage for outdoor-air exchange.

The system can bring outdoor air into areas such as:

  • Bedrooms
  • Living rooms
  • Other occupied spaces

while collecting exhaust air from appropriate locations elsewhere in the building.

The exact supply and exhaust design should follow the approved mechanical plans.

Does an ERV Replace Bathroom Exhaust Fans?

Not automatically.

Some ventilation designs can incorporate bathroom exhaust into a balanced whole-building system.

Other projects use separate local exhaust fans.

California also has local mechanical exhaust requirements for spaces such as bathrooms and kitchens.

The project-specific ventilation design determines how those requirements are satisfied.

Does an ERV Replace a Kitchen Range Hood?

Do not assume so.

Kitchen cooking exhaust has specific requirements and presents grease, moisture, and contaminant issues that are different from general whole-building ventilation.

A required range hood or other local kitchen exhaust system should not simply be eliminated because an ERV is installed.

Does an ERV Filter Outdoor Air?

ERV systems commonly contain filters.

The filtration protects equipment and can reduce particles entering with ventilation air.

The actual filtering performance depends on:

  • Filter type
  • Filter rating
  • Airflow
  • System design
  • Maintenance

An ERV should not automatically be described as an air purifier.

Can an ERV Improve Indoor Air Quality?

Controlled outdoor-air ventilation can support indoor air quality by replacing indoor air with outdoor air at a designed rate.

An ERV can make that process more energy efficient by recovering energy from the exhaust air.

Indoor air quality still depends on many other factors, including:

  • Outdoor-air quality
  • Source control
  • Filtration
  • Moisture control
  • Local exhaust
  • Building materials
  • Occupant activities

What Happens When Outdoor Air Quality Is Poor?

Outdoor air still needs to be considered as part of the ventilation design.

Filtration can reduce certain airborne particles, but filter effectiveness depends on the equipment and filter rating.

The system should be operated and maintained according to applicable requirements and manufacturer instructions.

Does an ERV Control Carbon Dioxide?

An ERV provides outdoor-air ventilation, which can dilute indoor contaminants generated by occupants.

However, the system does not chemically remove carbon dioxide through the recovery core.

The ventilation airflow itself provides the dilution effect.

Does an ERV Remove Odors?

Exhaust ventilation can help remove indoor air containing odors.

However, odor control depends on:

  • Exhaust location
  • Ventilation rate
  • Source strength
  • Equipment condition
  • Air-transfer characteristics

A ventilation system should be designed around the building rather than expected to eliminate every indoor odor.

Does an ERV Control Indoor Humidity?

An ERV can influence humidity because many models transfer latent energy.

It should not be relied upon as the only humidity-control strategy in every building.

Climate, occupancy, showers, cooking, HVAC operation, infiltration, and other factors also affect indoor moisture.

What Is an Energy Recovery Ventilator under California Title 24

How Does an Energy Recovery Ventilator Relate to Title 24?

California Requirements Depend on Building Type, Climate Zone and Compliance Path

For applicable permit applications filed on or after January 1, 2026, California uses the 2025 Building Energy Efficiency Standards.

The current Energy Code specifically addresses ERV and HRV systems in several residential, multifamily, and nonresidential ventilation provisions.

This does not mean every California building is required to have an ERV.

Applicability depends on:

  • Building type
  • Climate zone
  • Ventilation strategy
  • System configuration
  • Prescriptive or performance compliance
  • Project scope

For current official HVAC information, review the California Energy Commission HVAC Energy Code Support Center.

Does Every New California Home Need an ERV?

No universal statement should be made that every new California home requires an energy recovery ventilator.

Current requirements vary according to the applicable building category, climate zone, ventilation design, and selected compliance path.

An ERV can be:

  • Part of a prescriptive ventilation design
  • Part of a performance-based design
  • Used voluntarily as an energy-recovery measure
  • Unnecessary under another compliant ventilation strategy

The actual project should be reviewed before equipment is specified.

What About Multifamily Buildings?

The 2025 Energy Code contains specific multifamily requirements involving balanced ventilation and energy recovery.

Under the applicable prescriptive provisions, balanced ventilation systems in certain California climate zones must use an ERV or HRV.

Those climate zones include:

  • Climate Zone 1
  • Climate Zone 2
  • Climate Zone 4
  • Climate Zones 11 through 14
  • Climate Zone 16

For applicable systems serving individual dwelling units under that provision, the current code also establishes requirements involving:

  • Sensible recovery efficiency
  • Fan efficacy
  • Field verification

The project must be evaluated against the complete applicable code provision rather than using the climate-zone list by itself.

What Recovery Efficiency Does the Current Multifamily Prescriptive Path Require?

For the applicable 2025 multifamily balanced ventilation provisions in Climate Zones 1, 2, 4, 11–14, and 16, the current Energy Code establishes a minimum sensible recovery efficiency of 67 percent at the specified rating condition.

Applicable individual dwelling-unit systems also have fan-efficacy requirements.

These requirements apply to specific prescriptive configurations and should not be treated as a universal product specification for every ERV installed in California.

What Is a Fault Indicator Display?

The current California Energy Code includes fault-indicator-display requirements for applicable HRV and ERV systems serving dwelling units.

A fault indicator can alert the occupant or service provider when the ventilation equipment is not operating properly.

The current provisions also include applicable verification requirements.

This is an example of why an ERV selected for a permit project needs to satisfy more than airflow alone.

Does an ERV Require Field Verification?

Certain Title 24 ERV and HRV measures require field verification or acceptance testing.

Depending on building type and system configuration, verification can involve:

  • Ventilation airflow
  • Fan efficacy or fan power
  • Sensible recovery efficiency
  • System controls
  • Recovery bypass when applicable

The energy report can identify applicable requirements, but preparation of the report does not replace construction-stage testing.

What About Nonresidential Buildings?

The current 2025 Energy Code contains mechanical acceptance procedures involving:

  • Dedicated outdoor-air systems
  • Heat recovery ventilators
  • Energy recovery ventilators

when applicable.

The California Energy Commission publishes dedicated mechanical compliance and acceptance documentation for these systems.

Commercial projects should therefore coordinate ERV equipment with:

  • Mechanical plans
  • Ventilation calculations
  • Controls
  • Energy-compliance forms
  • Acceptance testing

For broader commercial assistance, review Title 24 compliance services.

Can an ERV Help a Performance Calculation?

Potentially.

Energy recovery can reduce heating or cooling energy associated with mechanical ventilation.

Under an applicable performance approach, the model may account for characteristics such as:

  • Ventilation airflow
  • Recovery efficiency
  • Fan power
  • Equipment controls

The benefit depends on the complete building design.

Adding an ERV does not automatically guarantee that a project will comply.

For additional information about the modeling process, review Title 24 energy calculations.

What Is an Energy Recovery Ventilator installation and ductwork

What Should Be Considered When Installing an ERV?

Airflow, Ductwork, Filters, Controls and Service Access All Matter

An ERV is not simply an appliance that can be placed anywhere and expected to perform correctly.

The installation needs to support the ventilation design.

Important considerations can include:

  • Equipment airflow capacity
  • Supply duct layout
  • Exhaust duct layout
  • Outdoor-air intake location
  • Exhaust-air termination
  • Filter access
  • Recovery-core access
  • Condensate management when applicable
  • Fan power
  • Controls
  • Noise
  • Service access

Where Should an ERV Be Installed?

Depending on the equipment and project, a unit might be located in:

  • A mechanical room
  • A utility room
  • A garage
  • A mechanical closet
  • A basement
  • An accessible rooftop location
  • Another approved serviceable location

California’s current code includes accessibility requirements for filters and HRV/ERV recovery cores in applicable dwelling-unit systems.

The unit should be serviceable after the building is completed.

Why Is Filter Access Important?

Filters need periodic maintenance.

If access is difficult, maintenance is more likely to be delayed.

Dirty filters can affect:

  • Airflow
  • Fan energy
  • Ventilation performance
  • Equipment condition

The ventilation design should therefore consider how the owner or service technician will reach the filters.

Does the Recovery Core Need Maintenance?

Yes.

Maintenance requirements vary by manufacturer.

The recovery core may require:

  • Inspection
  • Cleaning
  • Replacement

depending on the equipment.

Manufacturer instructions should be followed.

Can an ERV Be Installed in an Attic?

Some equipment can be located in an attic when allowed by the applicable code, manufacturer instructions, and project design.

However, service access becomes especially important.

California’s current Energy Code includes specific access provisions for certain HRV/ERV systems that require servicing from within an attic.

The design should therefore address access before construction is completed.

Does an ERV Need Condensate Drainage?

Depending on climate, equipment, and operating conditions, condensation can occur.

Some systems include condensate drainage provisions.

The manufacturer’s installation instructions and mechanical design should determine whether and how drainage is provided.

Where Should Outdoor Air Be Taken From?

The outdoor-air intake needs to be located where it can provide acceptable outdoor ventilation air and comply with applicable mechanical requirements.

It should not simply be placed next to an exhaust termination without considering recirculation.

Intake and exhaust locations should be coordinated on the plans.

Where Does Exhaust Air Come From?

Balanced ventilation systems commonly exhaust air from locations selected to support the ventilation design.

The exact layout varies.

General whole-building exhaust should also be coordinated with separate local exhaust requirements for bathrooms, kitchens, and other spaces where applicable.

Does Duct Sizing Matter?

Yes.

Undersized or poorly designed ducts can create excessive resistance.

That can:

  • Reduce airflow
  • Increase fan power
  • Increase noise
  • Prevent the installed system from reaching design ventilation rates

Ventilation ductwork should be sized and installed according to the equipment and design.

Does Balancing Matter?

Yes.

A balanced system should provide the intended relationship between supply and exhaust airflow.

Installation, duct resistance, filters, grilles, and fan settings can all affect the actual result.

This is one reason field verification may be required for applicable Title 24 projects.

What Is an Energy Recovery Ventilator Title 24 assistance from Alternative Energy Systems

Need Help With an ERV in Your Title 24 Design?

Call (626) 365-1518 | Alternative Energy Systems

If your architect, mechanical engineer, contractor, Title 24 report, or building department references an ERV, Alternative Energy Systems can review how the proposed system relates to the energy-compliance design.

Useful information can include:

  • Current floor plans
  • Mechanical plans
  • Ventilation calculations
  • ERV manufacturer and model when available
  • Design airflow
  • Recovery-efficiency information
  • Fan-power or fan-efficacy information
  • Duct layout
  • Controls
  • Existing Title 24 calculations
  • Building-department correction comments

What if the ERV Model Has Not Been Selected Yet?

Preliminary energy review can sometimes begin before a final model is selected.

However, enough information must eventually be provided to represent the actual proposed system.

The final equipment can affect:

  • Airflow
  • Recovery efficiency
  • Fan power
  • Electrical requirements
  • Controls
  • Physical installation

Final Title 24 documentation should correspond to the equipment intended for construction.

What if the Contractor Changes the ERV?

Send the new equipment specifications for review.

A replacement unit should not automatically be considered equivalent simply because it has the same nominal airflow.

Relevant differences can include:

  • Sensible recovery efficiency
  • Latent recovery characteristics
  • Fan power
  • Controls
  • Rated airflow
  • Bypass capability
  • Verification requirements

What if the Plans and Title 24 Report Do Not Match?

Resolve the discrepancy before construction whenever possible.

For example:

  • The report may specify an ERV while the mechanical plans show exhaust-only ventilation
  • The plans may show an ERV while the calculations assume another ventilation system
  • The equipment model may have changed
  • The design airflow may differ between documents

The energy documentation and mechanical plans should describe the same ventilation strategy.

What if the Building Department Requests a Correction?

Send AES:

  • The complete correction notice
  • The latest construction plans
  • The mechanical plans
  • The existing Title 24 report
  • The proposed ERV specifications

AES can determine whether the correction involves:

  • Ventilation airflow
  • Equipment performance
  • Fan efficacy
  • Recovery efficiency
  • Controls
  • Verification documentation
  • Plan coordination

What Information Does AES Need to Start?

The complete requirements depend on the project.

A useful starting package can include:

  • Floor plans
  • Mechanical plans
  • Equipment schedules
  • Ventilation specifications
  • Duct information
  • Existing energy calculations
  • Correction notices

For a broader intake guide, review what AES will need from you.

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides professional Title 24 calculations, energy-compliance documentation, revisions, and energy-related plan-check support throughout California.

AES brings more than 30 years of California energy-compliance experience to:

  • New residential construction
  • ADUs
  • Additions
  • Residential remodels
  • Multifamily projects
  • Mixed-use projects
  • Commercial construction
  • Tenant improvements
  • HVAC projects
  • Ventilation-system projects
  • Energy-related plan-check corrections

AES reviews the actual building and ventilation design instead of assuming that every ERV installation has the same California requirements.

Learn more through the About Us page, review company background on the clients page, or explore Title 24 energy analysis.

Understanding What Is an Energy Recovery Ventilator ultimately comes down to controlled ventilation with energy recovery.

The system supplies outdoor air and exhausts indoor air while transferring a portion of the thermal energy between those air streams.

Many ERVs can also transfer latent energy associated with moisture.

For a California Title 24 project, however, the important questions are more specific:

  • Is an ERV required or simply proposed?
  • What ventilation airflow is required?
  • What recovery efficiency is represented?
  • What fan power or efficacy applies?
  • Does the installed unit match the calculations?
  • Is field verification or acceptance testing required?

Alternative Energy Systems can review the project plans, ventilation design, ERV specifications, and existing energy documentation and determine how the equipment should be represented in the applicable compliance package.

Call (626) 365-1518, email info@title24energy.com, or use the contact page.

When service and payment have already been arranged, payment can be completed through the AES payment page.

Frequently Asked Questions: What Is an Energy Recovery Ventilator?

What Is an Energy Recovery Ventilator?

An energy recovery ventilator is a mechanical ventilation system that supplies outdoor air and exhausts indoor air while transferring a portion of sensible and, in many systems, latent energy between the two air streams.

What does ERV stand for?

ERV stands for energy recovery ventilator or energy recovery ventilation, depending on whether the term refers to the equipment or the process.

How does an ERV work?

Outdoor supply air and indoor exhaust air pass through separate paths in a recovery component that transfers energy between the air streams.

Does an ERV mix indoor and outdoor air?

The system is designed with separate supply and exhaust pathways. Energy is transferred through the recovery component rather than intentionally mixing the two air streams.

What is balanced ventilation?

Balanced ventilation uses mechanical supply and mechanical exhaust so incoming and outgoing airflow can be controlled together.

Is an ERV the same as an HRV?

No. Both recover sensible heat, while an ERV generally also transfers latent energy associated with moisture.

What is sensible heat?

Sensible heat is temperature-related thermal energy.

What is latent energy?

Latent energy is associated with moisture or water vapor in the air.

Does an ERV dehumidify a house?

An ERV can reduce some moisture-related ventilation load in appropriate conditions, but it should not automatically be treated as a dedicated dehumidifier.

Does an ERV heat or cool a house?

It preconditions ventilation air but generally does not replace the primary heating and cooling system.

Does an ERV bring fresh air inside?

It provides controlled outdoor-air ventilation. The actual outdoor-air quality and filtration still affect the quality of the supplied air.

Does an ERV filter the air?

ERV systems commonly include filters, but filtration performance depends on the equipment and selected filter.

Does an ERV replace an air purifier?

No. Its primary function is ventilation and energy recovery.

Does an ERV replace bathroom exhaust?

Not automatically. The mechanical design determines how whole-building ventilation and required local exhaust are provided.

Does an ERV replace a kitchen range hood?

Do not assume so. Cooking exhaust has separate requirements and should be evaluated independently.

Does an ERV control humidity?

It can influence humidity by transferring latent energy, but overall indoor humidity depends on many building and climate factors.

Does every California home need an ERV?

No. Applicability depends on building type, climate zone, ventilation strategy, project scope, and compliance path.

Does Title 24 recognize ERVs?

Yes. The 2025 California Energy Code contains specific ERV and HRV provisions for applicable residential, multifamily, and nonresidential systems.

Are ERVs required in multifamily buildings?

The 2025 prescriptive multifamily requirements specify ERV or HRV systems for certain balanced ventilation configurations in Climate Zones 1, 2, 4, 11–14, and 16.

What recovery efficiency is required?

For the applicable 2025 multifamily prescriptive configurations in those climate zones, the code establishes a minimum sensible recovery efficiency of 67 percent at the specified rating condition. Other projects can have different requirements.

Does fan energy matter?

Yes. California compliance can include fan-efficacy or fan-power requirements in addition to recovery efficiency.

Does an ERV require testing?

Applicable systems can require field verification or acceptance testing of airflow, fan performance, recovery performance, controls, or other characteristics.

What is a fault indicator display?

It is a feature used on applicable dwelling-unit HRV/ERV systems to indicate certain equipment faults. Current California requirements include FID provisions for applicable systems.

Where can an ERV be installed?

Depending on the equipment and design, it may be installed in a mechanical room, utility space, garage, mechanical closet, basement, accessible rooftop location, or another approved location.

Can an ERV be installed in an attic?

Some systems can be, but applicable access, service, manufacturer, and Energy Code requirements must be satisfied.

Does an ERV need maintenance?

Yes. Filters, recovery components, fans, intakes, exhausts, and other components require inspection and maintenance according to the manufacturer.

Why is filter access important?

Dirty filters can reduce airflow and increase fan energy, so the filters need to remain accessible for maintenance.

Does duct design matter?

Yes. Duct resistance can affect airflow, fan power, sound, and the ability of the system to deliver the required ventilation rate.

Can I change ERV models after the Title 24 report is complete?

Potentially, but the proposed replacement should be reviewed when its airflow, recovery efficiency, fan power, controls, or other characteristics differ from the analyzed equipment.

Can an ERV improve a Title 24 performance calculation?

Potentially. Energy recovery can reduce ventilation-related heating or cooling loads, but the actual compliance effect depends on the complete building and system design.

What Energy Code applies now?

For applicable permit applications filed on or after January 1, 2026, California uses the 2025 Building Energy Efficiency Standards.

What should I send AES for an ERV review?

Current plans, mechanical drawings, ventilation calculations, equipment specifications, design airflow, recovery-efficiency information, existing Title 24 calculations, and any building-department corrections are useful starting documents.

How do I get help with an ERV and Title 24?

Call Alternative Energy Systems at (626) 365-1518 and provide the current plans and ventilation-system information for review.

What Is a Heat Pump Water Heater?

What Is a Heat Pump Water Heater

What Is a Heat Pump Water Heater?

Call (626) 365-1518 | Alternative Energy Systems

What Is a Heat Pump Water Heater is becoming an increasingly important question for California homeowners, builders, architects, contractors, and designers because heat-pump technology now plays a major role in the state’s current Building Energy Efficiency Standards.

A heat pump water heater is an electric water-heating system that moves heat from surrounding air into stored water instead of relying primarily on electric resistance elements to create heat directly.

In simple terms, it works much like a refrigerator operating in reverse.

A refrigerator removes heat from the inside of the refrigerator and releases it into the room.

A heat pump water heater instead takes usable heat from the surrounding air and transfers that heat into the water stored in its tank.

The system typically uses:

  • An evaporator
  • Refrigerant
  • A compressor
  • A condenser or heat exchanger
  • A storage tank
  • Electronic controls
  • A fan
  • Backup electric resistance elements on many integrated units

Because the system primarily moves existing heat rather than producing all of its heat through electric resistance, it can use electricity differently and more efficiently than a conventional electric resistance storage water heater.

For general background about the underlying technology, review the heat pump article on Wikipedia.

Alternative Energy Systems provides Title 24 calculations and California energy-compliance documentation for residential, multifamily, mixed-use, and commercial projects.

Call (626) 365-1518 if your project includes a heat pump water heater and you need the equipment represented correctly in the Title 24 calculations and permit documentation.

How Does a Heat Pump Water Heater Work?

A heat pump water heater uses a refrigeration cycle to move thermal energy from air into water.

The basic process can be understood in several stages.

1. The Unit Pulls in Surrounding Air

A fan moves air across the evaporator.

Heat contained in that air is absorbed by refrigerant within the heat-pump system.

2. The Refrigerant Carries the Heat

The refrigerant changes condition as it absorbs heat.

The compressor then raises the refrigerant pressure and temperature.

3. Heat Is Transferred Into the Water

The heated refrigerant moves through a condenser or heat exchanger.

Thermal energy is transferred from the refrigerant into the water stored in the tank.

4. The Refrigerant Cycle Repeats

After releasing its heat, the refrigerant moves through the remaining refrigeration cycle and returns to the evaporator to collect more heat.

The process repeats whenever the water heater needs to restore the tank to the selected temperature.

The Unit Moves Heat Instead of Relying Only on Resistance Heating

A conventional electric resistance water heater sends electrical current through heating elements inside the tank.

Those elements become hot and transfer heat directly into the water.

A heat pump water heater instead uses electricity primarily to operate:

  • The compressor
  • The fan
  • The refrigerant cycle
  • The electronic controls

Many integrated heat pump water heaters also include conventional resistance elements for backup or high-demand operation.

That is why these systems are sometimes called hybrid electric water heaters.

Why Does the Air Around the Water Heater Matter?

Because the heat pump extracts heat from air, installation location matters.

The system needs an adequate source of air and appropriate ventilation.

A unit installed in a garage, utility room, mechanical room, closet, or other location may interact differently with the surrounding space.

The current California Energy Code includes specific ventilation requirements for heat pump water heater installations.

The project design should therefore consider both the appliance and the space around it.

What Is a Heat Pump Water Heater and how does it work

How a Heat Pump Water Heater Transfers Heat Into Water

Airflow, Refrigerant and a Compressor Replace Most Direct Resistance Heating

The difference between moving heat and creating heat directly is the central idea behind heat-pump technology.

That difference affects:

  • Energy use
  • Equipment design
  • Installation requirements
  • Location
  • Ventilation
  • Condensate management
  • Electrical requirements

What Is an Integrated Heat Pump Water Heater?

An integrated unit combines the heat-pump components and storage tank into one appliance.

The upper portion commonly contains:

  • Fan
  • Evaporator
  • Compressor
  • Controls

while the lower portion contains the insulated hot-water storage tank.

These units often resemble tall conventional electric storage water heaters, although the heat-pump equipment makes the upper portion larger.

What Is a Split Heat Pump Water Heater?

A split system separates some heat-pump components from the hot-water storage tank.

For example, a heat-pump unit may be installed separately from the tank and transfer heat into the stored water through an associated system.

The appropriate design depends on:

  • Building type
  • Equipment
  • Available installation space
  • Project design
  • Applicable Energy Code requirements

The equipment shown in the Title 24 documentation should correspond to the actual proposed system.

Why Do Many Units Still Have Electric Resistance Elements?

Many integrated systems include backup resistance elements to provide additional heating capacity.

The controls may use those elements when:

  • Hot-water demand is unusually high
  • The tank needs faster recovery
  • Operating conditions require supplemental heat
  • A selected operating mode allows resistance assistance

The exact control strategy depends on the appliance.

A heat pump water heater should therefore not automatically be described as having no resistance heating.

What Is Hybrid Mode?

Some equipment offers multiple operating modes.

These can include modes that prioritize:

  • Heat-pump operation
  • A combination of heat-pump and resistance operation
  • Faster recovery
  • Vacation or low-demand operation

Manufacturers use different terminology, so the actual product instructions should be reviewed.

Does a Heat Pump Water Heater Produce Cold Air?

The unit removes heat from the air passing across its evaporator.

As a result, discharged air can be cooler than the incoming air.

The heat pump can also remove moisture from the air during operation.

This interaction with the surrounding space is one reason installation location and ventilation need to be considered.

Does It Produce Condensate?

It can.

When warm air passes over the cold evaporator coil, moisture can condense.

The installation therefore normally needs an appropriate method for condensate drainage.

California electric-ready provisions for certain projects also recognize condensate-drain planning as an important part of preparing a future location for a heat pump water heater.

Does It Need a Fan?

Integrated air-source units commonly use a fan to move air across the evaporator.

Because a fan is operating, the appliance can also produce operating sound.

The equipment location should therefore account for:

  • Air movement
  • Noise
  • Access
  • Service clearances
  • Condensate drainage

What Is a Heat Pump Water Heater compared with electric and gas water heaters

Heat Pump Water Heater vs. Conventional Water Heating

The Main Difference Is How the Energy Is Converted Into Hot Water

Several water-heating technologies can provide domestic hot water, but they operate differently.

A project may involve:

  • Heat pump water heating
  • Electric resistance water heating
  • Natural-gas water heating
  • Propane water heating
  • Solar water heating
  • Central water-heating systems

The applicable Energy Code treatment depends on building type and project scope.

Heat Pump Water Heater vs. Electric Resistance Water Heater

Both can use electricity, but the primary heating process differs.

A conventional resistance unit creates heat directly at its electric elements.

A heat pump water heater uses a refrigeration cycle to move heat into the tank.

That distinction is important when the equipment is represented in energy calculations.

The two should not be entered as though they have identical performance characteristics.

Heat Pump Water Heater vs. Gas Water Heater

A gas-fired unit produces heat through combustion.

That normally involves:

  • Gas or propane supply
  • Combustion
  • Venting or exhaust requirements

An electric heat pump water heater does not use an on-site gas burner for its primary heat-pump operation.

Instead, it requires electrical service and an appropriate air-source installation environment.

The two technologies therefore create different design considerations.

Does a Heat Pump Water Heater Need a Flue?

An all-electric heat pump water heater does not need a combustion flue for heat-pump operation because it is not burning natural gas or propane.

However, it does require other installation considerations such as:

  • Electrical supply
  • Airflow
  • Ventilation when applicable
  • Condensate drainage
  • Manufacturer clearances

Is It the Same as a Tankless Water Heater?

No.

An integrated heat pump water heater typically uses a storage tank.

A tankless system heats water as demand occurs instead of storing a substantial quantity of hot water in a tank.

These systems have different operating characteristics and should not be treated as interchangeable in Title 24 calculations.

Is It the Same as a Solar Water Heater?

No.

A solar water-heating system captures solar thermal energy.

A heat pump water heater moves heat using an electrically powered refrigeration cycle.

The current California Energy Code can recognize both technologies in certain compliance situations, but they are fundamentally different systems.

Is It the Same as a Heat Pump Used for Space Heating?

The underlying refrigeration principles are similar, but the equipment has a different purpose.

A space-conditioning heat pump transfers heat to or from the building for heating and potentially cooling.

A heat pump water heater transfers heat into domestic hot water.

One system should not automatically be assumed to perform the function of the other.

What Is a Heat Pump Water Heater installation requirements

Where Can a Heat Pump Water Heater Be Installed?

Location, Airflow, Condensate and Electrical Service All Matter

Selecting the appliance is only one part of the design.

The installation location can affect how the heat pump operates and whether the proposed installation satisfies applicable requirements.

Can a Heat Pump Water Heater Be Installed in a Garage?

A garage can be a possible location for some residential installations.

The design still needs to account for:

  • Available space
  • Air volume
  • Ventilation
  • Electrical service
  • Condensate drainage
  • Clearances
  • Manufacturer instructions
  • Other applicable building requirements

Do not assume every garage installation is automatically identical.

Can It Be Installed in a Closet?

Potentially, but an enclosed location requires careful attention to airflow and ventilation.

Because the unit extracts heat from surrounding air, a small sealed closet may not provide the operating conditions required by the appliance or applicable Energy Code provisions.

Depending on the design, ducting or ventilation provisions may be needed.

The exact installation should follow the approved plans, applicable code requirements, and manufacturer instructions.

Can It Be Installed Indoors?

Yes, many units are designed for indoor installation.

However, indoor placement affects the surrounding space because the appliance:

  • Draws heat from the air
  • Discharges cooler air
  • Can remove moisture from the air
  • Produces condensate
  • Produces fan and compressor sound

Those characteristics should be considered during design.

Can the Tank Be Installed Outdoors?

The answer depends on the equipment and applicable Energy Code requirements.

For certain current single-family alteration compliance options involving heat pump water heaters, California specifically addresses storage-tank location and other installation criteria.

Do not assume that an indoor-rated integrated unit can simply be moved outdoors without reviewing the equipment requirements and Energy Code treatment.

Why Does Ventilation Matter?

California’s current Energy Code includes mandatory ventilation requirements when a heat pump water heater is installed.

The reason is practical: the appliance needs access to air from which it can extract heat.

Airflow and room configuration can affect performance.

The exact ventilation design should correspond to:

  • The equipment
  • The installation location
  • The applicable Energy Code section
  • The manufacturer’s instructions

Does the Unit Need a Condensate Drain?

A drainage path should be considered because moisture can condense on the evaporator during operation.

The required drainage configuration depends on the appliance and installation.

Condensate should not be treated as an afterthought after the water heater location has already been framed.

What Electrical Service Is Needed?

Electrical requirements vary by product.

Different heat pump water heater designs can require different:

  • Voltage
  • Circuit capacity
  • Breaker configuration
  • Electrical connection

The electrical design should follow the actual appliance specification rather than assuming every unit requires exactly the same circuit.

Why Should the Equipment Be Selected Before the Plans Are Final?

Early selection can help coordinate:

  • Electrical requirements
  • Equipment dimensions
  • Clearances
  • Ventilation
  • Condensate
  • Plumbing connections

Changing the equipment late in the permit process can require updates to the plans or energy documentation.

What Is a Heat Pump Water Heater under California Title 24

How Does a Heat Pump Water Heater Relate to Title 24?

The 2025 Energy Code Expands Heat-Pump Water Heating in Residential Construction

For applicable permit applications filed on or after January 1, 2026, California uses the 2025 Building Energy Efficiency Standards.

The current Energy Code places increased emphasis on heat pumps for both space heating and water heating.

For newly constructed single-family buildings using the applicable prescriptive water-heating path, the 2025 residential compliance guidance identifies:

  • A heat pump water heater
  • Or a qualifying solar water-heating system with electric backup

as the prescriptive water-heating approaches in all California climate zones.

That does not mean every existing building, alteration, multifamily building, or commercial project has the identical requirement.

Project classification and scope still matter.

For official current water-heating resources, review the California Energy Commission Water Heating information.

Does Every California Home Need a Heat Pump Water Heater?

No universal statement should be made that every existing California home must immediately replace its current water heater with a heat pump water heater.

Requirements depend on:

  • New construction versus existing construction
  • Alteration scope
  • Building type
  • Existing fuel source
  • Selected compliance path
  • Applicable Energy Code provisions

The current prescriptive requirements for a newly constructed single-family home are not identical to the rules for replacing a water heater in an existing home.

What About a New Single-Family Home?

For new single-family construction using the 2025 prescriptive compliance approach, heat pump water heating has a major role in the current water-heating requirements.

The Title 24 calculations and forms should represent the actual proposed equipment.

Relevant information can include:

  • Water-heater type
  • Tank size
  • Rated efficiency
  • Installation location
  • Distribution system
  • Other applicable water-heating measures

What About an ADU?

A new detached ADU can be subject to current new residential Energy Code requirements.

An attached ADU or conversion can have different conditions depending on the project scope.

Water-heating design can affect the Title 24 analysis.

The ADU may use:

  • Its own water heater
  • A system designed in relation to the existing building
  • Another project-specific configuration

For additional information, review ADU Title 24.

What About an Addition?

An addition does not automatically mean the existing water heater must always be replaced.

The answer depends on:

  • The addition
  • The existing system
  • The proposed water-heating design
  • The selected compliance method

The energy analysis should identify how domestic hot water is being served.

What About Replacing an Existing Water Heater?

Replacement water heating is treated as an alteration rather than new construction.

The 2025 Energy Code provides specific options for altered or replacement single-family water-heating systems.

Those options are not identical to the new-construction prescriptive requirement.

This is why an existing homeowner should not assume that every replacement project follows exactly the same rule as a new house.

What if I Already Have a Gas Water Heater?

The applicable alteration requirements should be reviewed before choosing the replacement equipment.

California’s current Energy Code contains project-specific provisions for replacement systems.

The building’s existing fuel connection, proposed equipment, installation conditions, and permit scope can all matter.

What Does Electric-Ready Mean?

Electric-ready requirements prepare certain buildings for future electrical equipment even when gas or propane equipment is initially installed.

For applicable single-family projects using gas or propane water heating, California can require provisions that facilitate later installation of a heat pump water heater.

These can involve:

  • Dedicated electrical infrastructure
  • Panel capacity or reserved breaker space
  • Equipment space
  • Condensate drainage provisions

The current requirements should be reviewed for the specific project.

Does Title 24 Calculate Water Heater Efficiency?

Water heating is one of the systems considered in applicable energy-compliance analysis.

The calculation can use equipment and distribution characteristics associated with the proposed design.

The energy documentation should not show one water-heating system while the plans specify another.

For more information about the broader calculation process, review Title 24 energy calculations.

What Is a Heat Pump Water Heater energy efficiency and installation

Why Heat Pump Water Heater Specifications Matter in an Energy Report

The Equipment in the Calculation Should Match the Equipment Being Installed

A Title 24 report is based on project-specific assumptions.

Water heating can be one of those assumptions.

If the report identifies a heat pump water heater, the design team should make sure the proposed installation remains consistent with the energy documentation.

What Information Does AES Need About the Water Heater?

Helpful information can include:

  • Water-heater type
  • Manufacturer when selected
  • Model when selected
  • Storage capacity
  • Rated efficiency
  • Fuel or energy source
  • Electrical requirements
  • Installation location
  • Hot-water distribution information

Not every specification needs to be final at the first preliminary review.

Enough information must eventually be available to prepare accurate final compliance documentation.

What if the Exact Model Has Not Been Selected Yet?

AES may be able to begin the analysis using the intended system type and available design information.

However, the final equipment should satisfy the assumptions and requirements represented in the approved documentation.

If the final product is materially different, the report may need review.

What if the Contractor Changes the Water Heater?

Send the replacement specification to AES when it differs from the equipment used in the analysis.

A substitution can change:

  • System type
  • Energy source
  • Rated efficiency
  • Storage capacity
  • Electrical requirements
  • Installation conditions

An apparently similar appliance is not automatically equivalent for energy-compliance purposes.

Can I Switch From a Heat Pump Water Heater to Gas?

Do not make that change solely at the construction stage without reviewing the approved energy design.

If the compliance analysis assumes heat pump water heating, changing to gas can alter:

  • Energy calculations
  • Plan notes
  • Electrical design
  • Gas design
  • Applicable compliance measures

The project may require revised calculations or a different compliance strategy.

Can I Change From Gas to a Heat Pump Water Heater?

Potentially.

The change still needs to be coordinated with:

  • Electrical service
  • Equipment space
  • Ventilation
  • Condensate drainage
  • Plumbing
  • Title 24 documentation

The equipment should be evaluated as part of the complete project rather than treated as an isolated substitution.

Can the Water Heater Affect Whether the Project Passes Title 24?

It can.

Under a performance-based compliance approach, water-heating characteristics can contribute to the overall energy analysis.

Changing a major energy system can therefore affect the compliance result.

The significance of the change depends on the project.

Does the Hot-Water Distribution System Matter?

Yes.

Water-heating compliance is not limited to the appliance.

Depending on the project, the hot-water distribution design can also matter.

That can involve:

  • Piping
  • Pipe insulation
  • Recirculation
  • Distribution configuration
  • Other applicable measures

The complete system should be represented accurately where required.

Do Water Pipes Need Insulation?

California’s Energy Code contains applicable hot-water-piping insulation requirements.

The exact requirements depend on the piping and project conditions.

The water heater itself should therefore not be considered independently from the distribution system.

What Software Is Used to Create Title 24 Reports

Where Heat Pump Water Heaters Appear in California Projects

New Homes, ADUs, Remodels and Equipment Replacements Can Have Different Rules

A heat pump water heater can appear in several project types.

The compliance treatment should be based on the actual scope.

New Residential Construction

New single-family construction under the current Energy Code can use heat pump water heating as a central part of the prescriptive design.

The project should establish:

  • Equipment type
  • Location
  • Electrical requirements
  • Ventilation
  • Condensate
  • Water distribution

before the permit documents are finalized.

ADU Construction

A new ADU can create its own domestic hot-water demand.

The proposed water-heating system should therefore be identified during the energy analysis.

Late changes can affect both the Title 24 report and construction drawings.

Garage Conversions

A garage conversion can create new conditioned residential space.

Depending on the design, the conversion may:

  • Use an existing water-heating system
  • Add a separate water heater
  • Require changes to hot-water distribution

The plans should clearly show the proposed design.

Residential Additions

An addition may extend the existing domestic hot-water system rather than install a new appliance.

The relevant question is whether the existing and proposed system can be represented appropriately under the applicable compliance path.

Residential Remodels

A remodel may include replacement of:

  • The water heater
  • Hot-water piping
  • Gas equipment
  • Electrical equipment

When water heating is part of the permitted work, the applicable current requirements should be reviewed.

Multifamily Projects

Multifamily water heating can be more complex.

The project can use:

  • Individual dwelling-unit systems
  • Central systems
  • Heat pump systems
  • Other qualifying configurations

Do not automatically apply a single-family water-heating rule to a multifamily project.

Commercial and Nonresidential Projects

Nonresidential buildings can have very different service-water-heating loads.

Examples include:

  • Offices
  • Restaurants
  • Retail buildings
  • Hotels
  • Other commercial occupancies

The system design should be evaluated using the applicable nonresidential requirements rather than assuming that one residential heat pump water heater fits every commercial application.

What Is a Heat Pump Water Heater advantages and project considerations

What Should Be Considered Before Choosing a Heat Pump Water Heater?

Efficiency Is Important, but the Installation Has to Work for the Building

Equipment selection should consider the complete project rather than one efficiency number.

Important questions include:

  • Where will the unit be installed?
  • Does the location provide appropriate airflow?
  • How will condensate be drained?
  • What electrical circuit is required?
  • How much hot water does the building need?
  • What tank capacity is appropriate?
  • Will surrounding-space cooling affect the location?
  • Will operating sound matter?
  • Can the unit be serviced easily?

Tank Capacity Matters

Because the system stores hot water, tank sizing is an important design consideration.

A household with relatively low demand can have different requirements from one with:

  • More occupants
  • Several bathrooms
  • Large tubs
  • High simultaneous hot-water demand

Equipment selection should reflect the actual building use.

Recovery Rate Matters

Recovery describes how quickly the system can restore hot water after the tank has been depleted.

A heat pump may recover differently from conventional resistance or gas heating.

Many integrated units use backup resistance elements to increase recovery when needed.

This is why tank capacity and operating mode can matter together.

Noise Can Matter

A heat pump water heater contains mechanical components.

These can include:

  • A compressor
  • A fan

The unit therefore generally produces more mechanical sound than a basic electric resistance storage tank.

Placement near bedrooms or quiet living spaces should be considered carefully.

Cooler Discharge Air Can Matter

Because the appliance extracts heat from surrounding air, its discharge can cool the nearby space.

That effect might be less significant in one installation and more noticeable in another.

The result depends on:

  • Room volume
  • Ventilation
  • Operating time
  • Building conditions

Condensate Can Matter

Condensate needs a reliable drainage path.

Improper planning can create avoidable installation problems after the appliance arrives.

The condensate route should therefore be considered during design rather than after construction is substantially complete.

Electrical Capacity Can Matter

Changing from a gas water heater to electric equipment can affect the electrical design.

The project may need to consider:

  • Panel capacity
  • Branch circuit
  • Breaker requirements
  • Equipment voltage

The actual appliance specification controls.

Will a Heat Pump Water Heater Always Cost Less to Operate?

No universal operating-cost promise should be made.

Actual cost depends on:

  • Electricity rates
  • Gas rates when comparing systems
  • Hot-water demand
  • Equipment efficiency
  • Operating mode
  • Installation conditions
  • Climate

The technology can reduce electricity use relative to conventional electric resistance water heating, but actual utility savings vary.

Will It Always Reduce My Utility Bill?

No specific savings amount should be guaranteed.

A household’s energy bill includes many variables beyond the water heater.

The appropriate comparison should use the actual equipment, energy rates, and hot-water demand.

Does It Work in Cold Weather?

Heat-pump performance can be affected by the temperature of the air supplying the unit.

California’s 2025 Energy Code contains specific requirements for certain installations involving outdoor inlet air and low-temperature operation.

That is another reason equipment selection and installation configuration matter.

What Is a Heat Pump Water Heater Title 24 assistance

Need Help With a Heat Pump Water Heater in Your Title 24 Design?

Call (626) 365-1518 | Alternative Energy Systems

If your architect, contractor, Title 24 report, building department, or equipment supplier specifies a heat pump water heater, Alternative Energy Systems can review how the proposed system relates to the energy-compliance design.

Helpful information can include:

  • Current plans
  • Water-heater specifications
  • Tank capacity
  • Equipment efficiency
  • Installation location
  • Electrical information
  • Hot-water distribution information
  • Existing Title 24 calculations
  • Building-department correction comments

What if the Plans and Energy Report Show Different Water Heaters?

Resolve the discrepancy before permit submission or construction whenever possible.

For example, the Title 24 report may specify a heat pump water heater while:

  • The plumbing plans show gas equipment
  • The architectural plans show a different location
  • The electrical plans omit the required circuit

Those documents should be coordinated.

What if the Building Department Requests a Correction?

Send AES:

  • The complete correction notice
  • The latest construction plans
  • The existing Title 24 report
  • The proposed water-heater specification
  • Updated electrical or plumbing information when applicable

AES can determine whether the correction involves:

  • Equipment information
  • Energy calculations
  • Compliance forms
  • Ventilation
  • Electrical readiness
  • Plan coordination

What if the Water Heater Is Changed After Permit Approval?

Have the change reviewed when it alters a system represented in the approved energy documentation.

Do not assume that changing from one technology to another is simply a field substitution.

The change can affect calculations and permit documents.

What Information Should I Send AES?

Before requesting or revising an energy report, useful documents can include:

  • Floor plans
  • Mechanical or plumbing information
  • Water-heater specifications
  • Electrical information
  • Existing energy documentation
  • Correction notices

For a broader intake guide, review what AES will need from you.

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides professional Title 24 energy calculations, compliance reports, revisions, and energy-related plan-check support throughout California.

AES brings more than 30 years of California energy-compliance experience to:

  • New homes
  • ADUs
  • Garage conversions
  • Additions
  • Residential remodels
  • Multifamily projects
  • Mixed-use projects
  • Commercial buildings
  • Tenant improvements
  • Water-heating changes
  • Energy-related plan-check corrections

AES evaluates the actual project and proposed systems rather than assuming every building has the same water-heating requirement.

Learn more through the About Us page, review company background on the clients page, or explore Title 24 compliance services.

Understanding What Is a Heat Pump Water Heater ultimately comes down to understanding how the appliance moves heat.

Instead of relying primarily on resistance elements or combustion to create heat, the heat pump uses electricity to transfer heat from air into stored water.

For California projects, the appliance can also affect:

  • Title 24 calculations
  • Electrical design
  • Equipment space
  • Ventilation
  • Condensate drainage
  • Water-heating compliance documentation

Alternative Energy Systems can review the plans and proposed water-heating system and determine how the equipment should be represented in the applicable California energy-compliance documentation.

Call (626) 365-1518, email info@title24energy.com, or use the contact page.

When service and payment have already been arranged, payment can be completed through the AES payment page.

Frequently Asked Questions: What Is a Heat Pump Water Heater?

What Is a Heat Pump Water Heater?

A heat pump water heater is an electric water-heating system that uses a refrigeration cycle to transfer heat from surrounding air into stored water.

How does a heat pump water heater work?

It uses an evaporator, refrigerant, compressor, condenser, fan, and controls to collect heat from air and transfer it into the water tank.

Is it electric?

Heat pump water heaters commonly use electricity to operate the compressor, fan, controls, and any supplemental electric heating elements.

Does it have a tank?

Many residential integrated heat pump water heaters include a storage tank, although other system configurations also exist.

Is it the same as a conventional electric water heater?

No. A conventional electric resistance water heater creates heat directly at resistance elements, while the heat pump primarily moves heat from air into the water.

Is it the same as a gas water heater?

No. A gas water heater uses combustion, while an electric heat pump water heater uses a refrigeration cycle.

Does it need a gas line?

An all-electric heat pump water heater does not require natural gas for its heat-pump operation.

Does it need a flue?

An all-electric heat pump water heater does not require a combustion flue because it does not burn fuel for heat-pump operation.

Does it have backup heating?

Many integrated units include electric resistance elements that can provide supplemental heating.

Why is it sometimes called a hybrid water heater?

Some units combine heat-pump operation with backup electric resistance heating, leading manufacturers to describe them as hybrid systems.

Does it need ventilation?

Airflow is important because the system extracts heat from air. California’s current Energy Code includes ventilation requirements for applicable heat pump water heater installations.

Does it create condensate?

It can. Moisture can condense on the evaporator, so an appropriate condensate drainage method is normally needed.

Does it make the room colder?

The discharge air can be cooler because the appliance removes heat from the incoming air.

Does it make noise?

The fan and compressor create operating sound, so equipment placement should be considered.

Can it be installed in a garage?

A garage can be suitable for some systems when the installation satisfies equipment, airflow, electrical, drainage, and other applicable requirements.

Can it be installed in a closet?

Potentially, but enclosed installations require appropriate airflow and ventilation and should follow the equipment and code requirements.

Does it need electricity?

Yes. Electrical requirements vary by product and should be determined from the selected equipment.

Does it use less electricity than a conventional resistance water heater?

Heat-pump technology can reduce electricity consumption relative to direct electric resistance water heating because it moves thermal energy rather than creating all heat through resistance elements.

Does it guarantee lower utility bills?

No. Actual operating costs depend on rates, hot-water demand, equipment performance, operating mode, climate, and installation.

Does Title 24 require heat pump water heaters?

The 2025 Energy Code places significant emphasis on heat pump water heating. For newly constructed single-family buildings using the applicable prescriptive path, current CEC guidance identifies heat pump water heating or a qualifying solar water-heating system with electric backup.

Does every existing house have to replace its water heater with a heat pump model?

No. Existing-building alterations and replacements have their own Energy Code provisions and should be reviewed separately from new construction.

What about a new ADU?

A new ADU can be subject to current residential water-heating requirements based on its project classification and compliance path.

What about an addition?

An addition does not automatically require replacement of the existing water heater. The existing and proposed system should be evaluated as part of the project.

What about replacing an existing gas water heater?

Replacement work is treated as an alteration, and the applicable 2025 Energy Code options should be reviewed for the specific project.

What does electric-ready mean?

Electric-ready provisions prepare applicable buildings for future electric equipment through features such as electrical capacity, equipment space, and condensate planning.

Can I change the water heater after the Title 24 calculations are complete?

Potentially, but the energy documentation should be reviewed when the proposed equipment differs materially from the system originally analyzed.

Can the water heater affect Title 24 compliance?

Yes. Water heating can be an input in the applicable energy analysis, especially under performance compliance.

Does hot-water piping matter?

Yes. Applicable piping, insulation, distribution, and recirculation requirements can also be part of Energy Code compliance.

What information should I send AES?

Current plans, proposed water-heater specifications, installation location, electrical information, existing Title 24 calculations, and any building-department corrections are useful starting documents.

What Energy Code applies now?

For applicable permit applications filed on or after January 1, 2026, California uses the 2025 Building Energy Efficiency Standards.

How do I get help with a heat pump water heater and Title 24?

Call Alternative Energy Systems at (626) 365-1518 and provide the current plans and proposed water-heating information for review.

What Is a Cool Roof?

What Is a Cool Roof

What Is a Cool Roof?

Call (626) 365-1518 | Alternative Energy Systems

What Is a Cool Roof is an important question when a California construction project involves new roofing, roof replacement, an addition, new construction, or a Title 24 energy analysis.

A cool roof is a roof designed to reduce the amount of solar heat absorbed by the building.

It does this primarily through roofing materials with properties that can:

  • Reflect more incoming solar energy
  • Release absorbed heat more effectively
  • Reduce roof-surface temperatures compared with less reflective roofing under similar conditions

In California energy compliance, cool-roof performance is commonly described using:

  • Solar reflectance
  • Thermal emittance
  • Solar Reflectance Index

These values allow roofing products to be evaluated by measured performance rather than simply by appearance or color.

A light-colored roof can sometimes have strong cool-roof characteristics, but color alone does not determine compliance.

Likewise, some darker roofing products can be manufactured with solar-reflective characteristics.

For a general background overview, review the cool roof article on Wikipedia.

Alternative Energy Systems provides Title 24 calculations and energy-compliance documentation for residential, multifamily, mixed-use, and commercial projects throughout California.

Call (626) 365-1518 if your plans, roofing specifications, Title 24 report, or building-department corrections reference a cool roof and you need help determining how that requirement applies to the project.

A Cool Roof Reduces Solar Heat Gain at the Roof Surface

Roofing receives substantial solar exposure.

When sunlight reaches a conventional roof, part of that solar energy is:

  • Reflected away from the roof
  • Absorbed by the roofing material
  • Transferred into or through the roof assembly
  • Released back to the surrounding environment as heat

A cool roof is designed to improve the roof’s response to that solar exposure.

By reflecting a greater portion of incoming solar energy and effectively releasing absorbed heat, the roof can operate at a lower surface temperature than a comparable roof with weaker solar-performance characteristics.

Cool Roof Performance Is About Measured Properties

A roof should not be called code-compliant simply because it looks reflective.

California energy compliance relies on rated roofing-product characteristics.

Relevant information can include:

  • Initial solar reflectance
  • Aged solar reflectance
  • Thermal emittance
  • Solar Reflectance Index
  • Roof slope
  • Product certification

The correct values should correspond to the actual roofing product proposed for the project.

What Is Solar Reflectance?

Solar reflectance describes the portion of incoming solar energy that a surface reflects rather than absorbs.

A roofing material with greater solar reflectance can send more solar energy away from the roof surface.

This characteristic can reduce the amount of solar heat absorbed by the roof.

For California Energy Code purposes, the applicable value may be an aged solar reflectance rather than only the initial value measured when the product is new.

Why Does Aged Solar Reflectance Matter?

Roofing materials can change as they are exposed to:

  • Sunlight
  • Weather
  • Dirt
  • Dust
  • Other outdoor conditions

Aged solar reflectance provides information about expected reflective performance after weathering rather than relying only on a new product’s initial performance.

This allows energy requirements to consider longer-term roofing characteristics.

What Is Thermal Emittance?

Thermal emittance describes a surface’s ability to release absorbed heat.

This is different from solar reflectance.

Solar reflectance concerns how much incoming solar energy is reflected.

Thermal emittance concerns how effectively absorbed heat can be emitted from the roofing surface.

Both characteristics can influence roof temperature.

What Is Solar Reflectance Index?

Solar Reflectance Index, commonly called SRI, combines solar reflectance and thermal emittance into a single roof-performance indicator.

California allows SRI to be used in applicable situations as an alternative method of demonstrating prescribed roof-surface performance.

This can provide flexibility because different combinations of reflectance and emittance can produce an acceptable SRI.

What Is a Cool Roof solar reflectance and thermal emittance

How Cool Roof Performance Is Measured

Solar Reflectance and Thermal Emittance Work Together

The performance of a cool roof cannot be judged reliably by looking at the material alone.

California uses rated product information so architects, consultants, contractors, building departments, and property owners can identify how a roofing product performs.

Who Rates Cool-Roof Products?

The California Energy Code uses roofing-product ratings associated with the Cool Roof Rating Council, commonly called the CRRC.

Applicable roofing products used for cool-roof compliance are certified and labeled so their rated properties can be identified.

A product label can contain information such as:

  • Solar reflectance
  • Thermal emittance
  • Weathered or aged performance
  • Product identification

The roofing material shown in the Title 24 documentation should correspond to the product ultimately installed.

Why Is the Product Label Important?

The label helps distinguish tested roofing performance from advertising claims.

A product may be described using words such as:

  • Reflective
  • Energy efficient
  • Heat resistant
  • Solar reflective

Those descriptions alone do not establish the values needed for Energy Code compliance.

The rated information provides measurable data that can be compared with the applicable requirements.

Does a Cool Roof Have to Be White?

No.

White roofing materials are commonly associated with high solar reflectance, especially on low-sloped roofs, but cool-roof products are not limited to white.

Manufacturers can produce roofing materials in a variety of colors and types.

Depending on the product, reflective pigments or other technologies can improve solar performance while maintaining a different appearance.

The important issue for compliance is the rated product performance, not simply whether the roof appears white.

Can a Dark Roof Be a Cool Roof?

Potentially.

A darker roofing product can have solar-performance characteristics that differ substantially from another product of a visually similar color.

That is why the rated solar reflectance, thermal emittance, or SRI should be checked instead of making a decision based entirely on appearance.

What Types of Roofing Can Be Cool Roofs?

Cool-roof characteristics can be available in several roofing categories.

Depending on the building and roof design, products can include:

  • Roof membranes
  • Roof coatings
  • Metal roofing
  • Roof tiles
  • Shingles
  • Other qualifying roofing products

Not every product within these categories automatically qualifies for a particular Energy Code requirement.

The specific rated product should be checked.

Does Roof Slope Matter?

Yes.

California distinguishes between low-sloped and steep-sloped roofs for various Energy Code provisions.

Roof slope can affect:

  • Which cool-roof criteria apply
  • Applicable reflectance requirements
  • Applicable SRI requirements
  • Available exceptions
  • Prescriptive compliance options

Do not assume that a roofing product appropriate for one roof configuration automatically satisfies the requirements for another.

What Is a Low-Sloped Roof?

California Energy Code provisions define roof-slope categories using the relationship between vertical rise and horizontal run.

Low-sloped roofs are commonly associated with commercial buildings, multifamily buildings, and some residential designs.

They often use:

  • Single-ply membranes
  • Built-up roofing
  • Modified bitumen
  • Roof coatings
  • Other low-slope roofing systems

The applicable Title 24 requirements depend on the project.

What Is a Steep-Sloped Roof?

Steep-sloped roofs are common on houses and other buildings using pitched roof construction.

Common roofing can include:

  • Composition shingles
  • Tile
  • Metal roofing
  • Other pitched-roof products

The cool-roof criteria for steep-sloped construction can differ from those applied to low-sloped roofs.

What Is a Cool Roof CRRC ratings and roof slope

Cool Roof Ratings Depend on the Actual Roofing Product

Roof Slope, Product Type and Climate Zone Can Change the Requirements

California does not apply one identical cool-roof requirement to every roof.

The project must be evaluated according to the applicable Energy Code provisions.

Factors can include:

  • Single-family, multifamily, or nonresidential building type
  • New construction
  • Addition
  • Alteration
  • Roof replacement
  • Roof slope
  • Climate zone
  • Prescriptive or performance compliance

How Does Climate Zone Affect Cool-Roof Requirements?

California contains 16 building climate zones.

These zones reflect regional differences in heating, cooling, temperature, and other climate conditions.

Because roof solar performance can have different effects in different climates, cool-roof requirements can vary according to project location.

The same roofing product should therefore not automatically be assumed to satisfy every project in every California climate zone.

For additional information, review why Title 24 standards vary by climate zone.

Does Building Type Matter?

Yes.

California Energy Code requirements distinguish among:

  • Single-family buildings
  • Multifamily buildings
  • Nonresidential buildings

A roofing requirement associated with a commercial building should not automatically be applied to a single-family house without checking the applicable standards.

Likewise, multifamily projects have their own current compliance provisions.

Is a Cool Roof Required on Every California Building?

No.

A universal statement that every California building must have a cool roof would be inaccurate.

The current Energy Code contains project-specific prescriptive requirements, exceptions, alternative compliance methods, and performance approaches.

Whether a cool roof is required or used for compliance can depend on:

  • Climate zone
  • Building type
  • Roof slope
  • Roof construction
  • Project scope
  • Compliance approach

The project should be evaluated before a roofing specification is finalized.

Can Performance Compliance Allow a Different Roof?

Potentially.

For applicable projects using performance compliance, a proposed roof can sometimes have different characteristics from the prescriptive values when the complete building still satisfies the applicable energy-performance requirements.

That does not mean every roof choice will work.

The effect needs to be evaluated through the applicable Title 24 calculation.

Other building features may need to provide sufficient energy performance to offset a roof that does not follow the basic prescriptive configuration.

Can Additional Insulation Affect Cool-Roof Compliance?

In some applicable roof configurations, the Energy Code provides insulation-related tradeoffs or exceptions.

This is particularly important because roof energy performance involves more than exterior surface color.

The complete roof assembly can include:

  • Roofing material
  • Roof deck
  • Continuous insulation
  • Cavity insulation
  • Attic space
  • Ceiling insulation

The correct compliance strategy should be determined from the applicable code requirements rather than assumed from one component alone.

Can Solar Panels Affect the Cool-Roof Requirement?

Certain Energy Code provisions contain exceptions for roof areas occupied by qualifying building-integrated photovoltaic or solar-thermal systems.

The exact treatment depends on the building and code provision.

Standard rooftop solar panels and building-integrated products should not automatically be treated as identical.

The actual roof design needs to be reviewed.

Can Heavy Roof Construction Affect the Requirement?

Some California Energy Code provisions include exceptions for qualifying high-mass roof construction.

These provisions are project-specific.

Do not assume that tile, concrete, stone, or another heavy material automatically creates an exception without confirming the required construction and applicable code section.

What Is a Cool Roof under California Title 24

How Does a Cool Roof Relate to Title 24?

California Requirements Vary by Building, Roof and Compliance Method

A cool roof can be one component of a California energy-compliance design.

It may appear in:

  • Prescriptive requirements
  • Performance calculations
  • Roof-alteration requirements
  • Compliance forms
  • Architectural roof specifications

The Title 24 report and construction plans should agree on the roofing performance used for compliance.

What Happens if the Title 24 Report Specifies a Cool Roof?

If the energy documentation relies on a cool roof, the roofing installed during construction should meet the specifications represented in that analysis.

The project team should verify:

  • Roofing product
  • Rated solar reflectance
  • Thermal emittance
  • SRI when applicable
  • Roof slope
  • Applicable certification information

Installing a substantially different roofing product can create a mismatch between the approved calculations and construction.

Can I Change the Roof After the Calculations Are Finished?

Potentially, but the calculation should be reviewed when the change affects an energy characteristic represented in the approved design.

A roofing substitution can change:

  • Solar reflectance
  • Thermal emittance
  • SRI
  • Roof assembly
  • Insulation strategy

A product that appears similar visually may not have the same rated characteristics.

Can I Remove a Cool-Roof Requirement From My Project?

Possibly, depending on the project and available compliance options.

However, do not remove the requirement from the plans without checking the energy analysis.

If the roof characteristics are part of the compliant design, another measure or revised calculation may be necessary.

For more information about how project features interact, review Title 24 energy calculations.

Can I Add a Cool Roof to Improve Energy Performance?

A higher-performing roofing product can potentially improve roof-related energy performance.

Whether that change materially affects a Title 24 calculation depends on:

  • Building type
  • Climate zone
  • Roof area
  • Roof slope
  • Other envelope features
  • Compliance method

The effect should be evaluated within the complete project.

What Code Is Currently Used?

For applicable permit applications filed on or after January 1, 2026, California uses the 2025 Building Energy Efficiency Standards.

The 2025 Energy Code includes current roof-envelope requirements for residential, multifamily, and nonresidential buildings.

For official information, review the California Energy Commission 2025 Building Energy Efficiency Standards.

The 2025 Code Includes Cool-Roof Compliance Documentation

The current California compliance materials include provisions and forms relating to roof-envelope performance.

For single-family projects, the California Energy Commission provides a Solar Reflectance Index calculation worksheet among the current envelope compliance documents.

The exact documents required depend on the project.

Why Should the Plans and Energy Report Match?

The architectural plans may identify:

  • Roofing type
  • Roof slope
  • Roof color or finish
  • Roof insulation
  • Roof assembly

The energy analysis can use corresponding performance values.

If those documents describe different roofing systems, the building department may request clarification or revision.

What Is a Cool Roof for existing buildings and roof replacement

What About Cool Roofs on Existing Buildings?

Roof Replacement, Roof Recover and Repair Are Not Always Treated the Same

Existing-building roofing work can be subject to different requirements depending on the scope.

California distinguishes among different types of roofing work.

These can include:

  • Roof replacement
  • Roof recover
  • Roof recoating
  • Roof repair

The scope matters because a limited repair is not necessarily treated the same as replacing a substantial portion of the roof.

What Is a Roof Replacement?

A roof replacement generally involves removal of the existing roof covering followed by repair of the substrate as needed and installation of a new roof covering.

When an applicable replacement triggers Energy Code requirements, roofing characteristics may need to comply with current provisions.

What Is a Roof Recover?

A roof recover places an additional roofing layer over an existing prepared roof covering rather than removing the existing covering entirely.

Applicable Energy Code treatment can differ according to:

  • Building type
  • Roof slope
  • Area affected
  • Climate zone
  • Existing construction

What Is a Roof Recoat?

A roof recoat generally involves application of a fluid-adhered coating as part of roof maintenance or repair.

Roof coating products can also have solar-reflective properties.

However, the project scope and applicable code provisions should be reviewed before assuming that recoating creates the same requirements as complete roof replacement.

Does Every Roof Repair Need a Cool Roof?

No.

Limited roof repairs can be treated differently from qualifying roof replacements or alterations.

The amount of roof area being changed and the nature of the work can matter.

The project should be evaluated based on what is actually being replaced rather than simply using the word “roofing” for every scope.

Does Reroofing Trigger Title 24?

It can.

Applicable reroofing work can trigger Energy Code requirements for roofing products and, depending on the project, other roof-envelope measures.

However, requirements differ among:

  • Single-family buildings
  • Multifamily buildings
  • Nonresidential buildings
  • Low-sloped roofs
  • Steep-sloped roofs
  • Different climate zones

Do not assume that every reroof requires the same cool-roof product.

What if My Existing Roof Does Not Meet Current Cool-Roof Values?

An existing roof is not automatically required to be replaced merely because a newer Energy Code exists.

Current requirements generally become relevant according to the work being performed.

If the roof is being altered or replaced, the new work should be reviewed under the applicable current requirements.

Can Existing Insulation Affect a Roof Alteration?

Potentially.

Current Energy Code provisions can consider existing or proposed roof insulation in certain alteration situations.

This is why the complete roof assembly should be reviewed rather than looking only at the exterior roofing material.

What Information Should I Provide for a Reroofing Project?

Useful information can include:

  • Building type
  • Project address
  • Roof plan
  • Roof slope
  • Existing roofing
  • Proposed roofing product
  • Roof area being replaced
  • Existing insulation
  • Proposed insulation
  • Existing Title 24 documentation
  • Building-department correction comments

AES can review the energy-compliance implications of the proposed scope.

What Is a Cool Roof compared with a radiant barrier and insulation

Cool Roof vs. Radiant Barrier and Insulation

These Roof Measures Work in Different Ways

A cool roof, radiant barrier, and thermal insulation can all influence heat transfer through a roof system, but they do not perform the same function.

Cool Roof vs. Radiant Barrier

A cool roof works at or near the exterior roof surface.

Its performance is associated with how the roofing responds to solar energy.

A radiant barrier is generally located below the exterior roof surface within the roof-and-attic assembly.

Its purpose is to reduce radiant heat exchange within that assembly.

The two measures therefore address different stages of heat transfer.

Can a Building Have Both?

Yes.

A roof-and-attic system can potentially include:

  • A cool-roof exterior surface
  • A radiant barrier below the roof deck
  • Ceiling or roof insulation

Whether all of those measures are necessary depends on the project.

For additional information, review the related page on What Is a Radiant Barrier.

Cool Roof vs. Insulation

Roof or ceiling insulation resists conductive heat flow through the building envelope.

A cool roof instead changes how the exterior roof surface responds to solar radiation.

One should not automatically be substituted for the other.

However, certain Energy Code provisions can allow specific tradeoffs involving roof insulation and solar reflectance.

Does a Cool Roof Eliminate the Need for Insulation?

No general rule allows a cool-roof product to replace all required roof or ceiling insulation.

Insulation requirements remain part of the applicable building-envelope design.

The exact assembly should follow the Title 24 analysis and construction plans.

Does a Cool Roof Eliminate the Need for a Radiant Barrier?

Not automatically.

The two measures address different heat-transfer mechanisms.

Whether a radiant barrier is required or modeled separately depends on the project and compliance strategy.

Does a Cool Roof Guarantee Lower Energy Bills?

No specific utility savings should be guaranteed.

Actual energy use depends on many factors, including:

  • Climate
  • Roof area
  • Building orientation
  • Insulation
  • Windows
  • HVAC efficiency
  • Duct conditions
  • Occupant behavior
  • Thermostat settings

A cool roof is one building-envelope measure rather than a guarantee of a particular energy bill.

Can a Cool Roof Reduce Roof Temperature?

A roofing material with stronger solar reflectance and thermal emittance can operate at a lower surface temperature than a less reflective product under comparable solar conditions.

The actual temperature difference varies with:

  • Sun exposure
  • Weather
  • Roof material
  • Roof color
  • Rated performance
  • Building configuration

Can a Cool Roof Help Reduce Cooling Loads?

Reducing solar heat absorbed at the roof can reduce heat entering the roof assembly.

How much that affects cooling demand depends on the complete building.

The Title 24 performance method can evaluate the roof together with other building features when applicable.

Is a Cool Roof Always Better in Every Climate?

Not necessarily in exactly the same way.

California’s use of climate zones recognizes that buildings experience different heating and cooling conditions.

That is why cool-roof requirements vary instead of applying one identical roof specification throughout the state.

What Is a Cool Roof Title 24 help from Alternative Energy Systems

Need Help With a Cool Roof or Title 24 Roof Requirement?

Call (626) 365-1518 | Alternative Energy Systems

If your Title 24 report, construction plans, roofing contractor, architect, or building department references a cool roof, AES can review the energy-compliance side of the project.

Useful documents can include:

  • Current construction plans
  • Roof plans
  • Building sections
  • Roof slope
  • Roofing-product specifications
  • CRRC product information when available
  • Insulation information
  • Existing Title 24 calculations
  • Building-department corrections

What if My Contractor Wants to Substitute a Different Roof?

Send the proposed roofing information for review before assuming it is equivalent.

Useful product information can include:

  • Manufacturer
  • Product name
  • Color
  • Rated solar reflectance
  • Rated thermal emittance
  • SRI when applicable

AES can compare the proposed change with the existing energy documentation.

What if My Plans Do Not Show the Cool-Roof Requirement?

If the Title 24 analysis depends on a particular roofing characteristic, the plans should be coordinated so the construction team can identify what needs to be installed.

A mismatch between the report and architectural plans can create:

  • Plan-check questions
  • Product-ordering mistakes
  • Construction changes
  • Energy-report revisions

What if the Building Department Requests a Correction?

Send AES:

  • The complete correction notice
  • The latest plans
  • The existing energy report
  • The proposed roofing specifications
  • Any revised roof details

AES can determine whether the correction requires:

  • A product clarification
  • Updated roof values
  • Revised Title 24 calculations
  • Updated forms
  • Coordination with the architectural plans

What Information Is Needed Before Title 24 Calculations Are Updated?

For broader project-document requirements, review what AES will need from you.

Energy calculations should be based on the actual proposed roof rather than an assumed product that will later be replaced.

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides professional Title 24 calculations, energy-compliance reports, revisions, and plan-check support throughout California.

AES brings more than 30 years of California energy-compliance experience to:

  • New residential construction
  • ADUs
  • Garage conversions
  • Additions
  • Residential remodels
  • Multifamily projects
  • Mixed-use projects
  • Commercial construction
  • Tenant improvements
  • Roof alterations
  • Energy-related plan-check corrections

AES evaluates the actual project rather than assuming that every roof in California has the same cool-roof requirement.

Learn more through the About Us page, review company background on the clients page, or explore Title 24 compliance services.

Understanding What Is a Cool Roof comes down to measurable roof-surface performance.

A cool roof is designed to reflect more incoming solar energy and release absorbed heat effectively.

For Title 24 purposes, however, the important question is not simply whether a roofing product is marketed as “cool.”

The project must use the correct:

  • Roof classification
  • Climate zone
  • Rated roofing values
  • Compliance method
  • Applicable Energy Code requirements

Alternative Energy Systems can review your project plans, roofing specifications, existing Title 24 calculations, and building-department comments to determine how the proposed roof should be represented in the energy documentation.

Call (626) 365-1518, email info@title24energy.com, or use the contact page.

When service and payment have already been arranged, payment can be completed through the AES payment page.

Frequently Asked Questions: What Is a Cool Roof?

What Is a Cool Roof?

A cool roof is a roofing system designed to reflect more incoming solar energy and effectively release absorbed heat compared with roofing products that have weaker solar-performance characteristics.

How does a cool roof work?

It reduces solar heat absorption through roofing characteristics such as solar reflectance and thermal emittance.

What is solar reflectance?

Solar reflectance describes the portion of incoming solar energy that a roofing surface reflects rather than absorbs.

What is aged solar reflectance?

Aged solar reflectance represents roofing reflectance after weathering rather than only the product’s initial performance.

What is thermal emittance?

Thermal emittance describes how effectively a surface releases absorbed heat.

What is SRI?

Solar Reflectance Index combines solar reflectance and thermal emittance into a roof-performance indicator that can be used in applicable compliance situations.

Does a cool roof have to be white?

No. Roofing products of different colors can have qualifying solar-performance characteristics.

Can a dark roof qualify?

Potentially. The rated product values matter more than visual color alone.

Who rates cool-roof products?

California Energy Code compliance uses applicable roofing-product ratings and labeling associated with the Cool Roof Rating Council.

Does every California roof need to be a cool roof?

No. Requirements vary according to building type, climate zone, roof slope, project scope, and compliance method.

Does Title 24 require a cool roof?

Title 24 contains cool-roof requirements for applicable projects, but those requirements are not identical for every building or roof.

Does climate zone matter?

Yes. California’s roof requirements can vary among its 16 building climate zones.

Does roof slope matter?

Yes. Low-sloped and steep-sloped roofs can have different applicable requirements.

What is a low-sloped roof?

It is a roof within the Energy Code’s lower-slope classification. The exact classification should be determined from the applicable code definition.

What is a steep-sloped roof?

California identifies steep-sloped roofs separately from low-sloped roofs, and different prescriptive requirements can apply.

Do residential and commercial buildings have the same cool-roof requirements?

No. Single-family, multifamily, and nonresidential buildings can have different applicable provisions.

Can performance compliance allow a different roofing product?

Potentially. In applicable performance projects, the complete building can be evaluated when the proposed roof differs from the prescriptive configuration.

Can additional insulation affect the roof requirement?

Certain Energy Code provisions provide applicable insulation tradeoffs or exceptions, depending on the project.

Can solar panels affect cool-roof requirements?

Certain code provisions include exceptions for qualifying building-integrated photovoltaic or solar-thermal roof areas.

Does reroofing trigger cool-roof requirements?

It can. The applicable requirements depend on building type, climate zone, roof slope, area affected, and the type of roofing alteration.

Does a small roof repair require a cool roof?

Not every limited repair is treated the same as an applicable roof replacement or alteration.

Can I use any reflective roof coating?

Do not assume so. The product should have the appropriate rated characteristics when it is being used for Energy Code compliance.

Can I change the roof product after my Title 24 report is completed?

Potentially, but the report should be reviewed when the new product has different solar reflectance, thermal emittance, SRI, or other relevant characteristics.

Can a cool roof replace insulation?

No universal rule allows a cool roof to replace all required insulation. The complete roof assembly must meet applicable Energy Code requirements.

Is a cool roof the same as a radiant barrier?

No. A cool roof works at the exterior roof surface, while a radiant barrier typically reduces radiant heat transfer within the roof-and-attic assembly.

Can a building have both a cool roof and radiant barrier?

Yes, depending on the building design and energy-compliance strategy.

Does a cool roof guarantee lower utility bills?

No. Actual energy use depends on the complete building, climate, HVAC systems, insulation, occupancy, and other factors.

What Energy Code applies now?

For applicable permit applications filed on or after January 1, 2026, California uses the 2025 Building Energy Efficiency Standards.

What should I send AES for a roof review?

Current plans, roof plans, roof slope, proposed roofing specifications, insulation information, existing Title 24 calculations, and any building-department corrections are useful starting documents.

How do I get help with a cool-roof requirement?

Call Alternative Energy Systems at (626) 365-1518 and provide the current plans and proposed roofing information for review.

What Is a Radiant Barrier?

What Is a Radiant Barrier

What Is a Radiant Barrier?

Call (626) 365-1518 | Alternative Energy Systems

What Is a Radiant Barrier is an important question when a California construction project includes an attic, roof assembly, energy calculation, or Title 24 requirement that references this type of building-envelope material.

A radiant barrier is a reflective material designed to reduce the transfer of radiant heat.

In a typical attic application, the material is installed near the roof structure with a low-emittance reflective surface facing the attic space.

Its purpose is to reduce the amount of radiant heat transferred from the hot roof assembly toward the surfaces and spaces below.

A radiant barrier is commonly associated with:

  • Attics
  • Roof decking
  • Roof trusses
  • Roof rafters
  • Gable-end walls
  • Residential energy-compliance designs
  • Title 24 calculations when applicable

It should not be confused with ordinary fiberglass, cellulose, mineral wool, rigid foam, or other conventional thermal insulation.

Those materials primarily resist heat flow through their thermal resistance.

A radiant barrier works differently by reducing radiant heat transfer from a hot surface.

The two systems can therefore work together rather than serving as direct substitutes for one another.

For a general technical overview of the material, review the radiant barrier article on Wikipedia.

Alternative Energy Systems provides California Title 24 calculations and energy-compliance documentation for residential, multifamily, mixed-use, and commercial projects.

Call (626) 365-1518 if a radiant barrier appears on your plans, energy report, correction notice, or proposed roof assembly and you need help determining how it relates to the Title 24 analysis.

How Does a Radiant Barrier Work?

Heat can move through a building in several ways.

Those include:

  • Conduction
  • Convection
  • Radiation

A radiant barrier specifically addresses radiant heat transfer.

On a hot day, solar energy heats the roofing material and roof deck.

That heated roof assembly can radiate energy toward other surfaces inside the attic.

A properly installed radiant barrier has a reflective, low-emittance surface that reduces this radiant exchange.

That can reduce the amount of heat being transferred toward:

  • Attic insulation
  • Ductwork
  • Ceiling surfaces
  • Other attic components

The radiant barrier does not make the attic cold.

It reduces one path through which heat moves through the roof-and-attic system.

What Does Low Emittance Mean?

Emittance describes how readily a surface emits radiant energy.

A low-emittance surface emits less radiant energy than a high-emittance surface under similar conditions.

That is why radiant barriers typically use a reflective metallic surface.

For applicable California Energy Code treatment, the material must satisfy specific performance criteria.

Under the current 2025 residential reference criteria, a radiant barrier used for applicable compliance credit has an emittance of no more than 0.05 when tested using the specified standards.

The product and installation must also satisfy other applicable California requirements.

A Radiant Barrier Is More Than Something That Looks Shiny

A reflective-looking surface should not automatically be treated as a compliant radiant barrier.

The material needs to have the appropriate tested properties and be installed in a qualifying configuration.

For California energy-compliance purposes, relevant factors can include:

  • Product emittance
  • Product certification
  • Installation location
  • Orientation of the reflective surface
  • Air-space configuration
  • Coverage of required attic surfaces
  • Attic ventilation when applicable

This is why a material should not be substituted during construction simply because another product appears visually similar.

What Is a Radiant Barrier and how does it work

How a Radiant Barrier Reduces Heat Transfer

It Targets Radiant Heat Rather Than Replacing Conventional Insulation

A radiant barrier is most useful to understand as one component of a complete roof-and-attic system.

The system can also include:

  • Roofing material
  • Roof deck
  • Attic ventilation
  • Ceiling insulation
  • Ductwork
  • Mechanical equipment
  • Air sealing

Each of these components can affect building energy performance differently.

Is a Radiant Barrier the Same as Insulation?

No.

A radiant barrier and thermal insulation perform different functions.

Traditional insulation is generally rated according to thermal resistance, commonly expressed as an R-value.

It slows conductive heat transfer through assemblies such as:

  • Walls
  • Ceilings
  • Roofs
  • Floors

A radiant barrier primarily reduces radiant heat exchange.

It normally depends on the reflective surface facing an air space so that the low-emittance surface can perform its intended function.

Does a Radiant Barrier Have an R-Value?

The radiant barrier itself should not be treated the same way as conventional insulation solely by assigning it the R-value of a bulk insulation material.

Its primary function is based on surface emittance and radiant heat transfer.

Some manufactured building products combine reflective surfaces with insulation.

In those cases, the complete product may have additional thermal properties.

However, the reflective layer and the insulation component should not be treated as though they perform exactly the same function.

Can a Radiant Barrier Replace Attic Insulation?

Generally, a radiant barrier should not be viewed as a direct replacement for required ceiling or roof insulation.

A building may contain both:

  • Conventional insulation to resist conductive heat flow
  • A radiant barrier to reduce radiant heat transfer

The applicable Title 24 analysis determines which envelope measures are part of the compliant design.

If the plans require a particular insulation assembly, installing a radiant barrier does not automatically eliminate that insulation requirement.

Why Is an Air Space Important?

The reflective surface of a radiant barrier generally needs to face an air space for the radiant-barrier effect to function as intended.

If the reflective face is sandwiched tightly between solid materials without an appropriate air space, the heat-transfer conditions are different.

California’s residential reference criteria therefore identify specific acceptable installation arrangements.

The correct installation depends on the roof construction and the particular product being used.

Which Side of a Radiant Barrier Faces the Attic?

For the California attic configurations addressed by the current residential reference criteria, the shiny or low-emittance surface is generally oriented downward toward the interior of the building or attic floor.

The exact installation should follow:

  • The applicable Energy Code requirements
  • California reference criteria
  • Manufacturer instructions
  • The approved plans

Do not reverse the material simply because both sides appear similar.

Where Is a Radiant Barrier Installed?

Several installation approaches can be used when they satisfy the applicable requirements.

Examples identified in California residential reference criteria include radiant barriers:

  • Draped over the top of roof trusses or rafters before decking is installed
  • Installed between trusses or rafters
  • Attached to the bottom surface of the trusses or rafters
  • Laminated directly to the underside of roof decking

The installation method affects required spacing and other details.

Radiant Barrier Roof Sheathing Is Common in New Construction

One common construction method uses roof sheathing manufactured with a reflective radiant-barrier surface already bonded to the underside.

This can simplify installation because the reflective layer becomes part of the roof sheathing product.

The sheathing still needs to be installed in the correct orientation.

When radiant-barrier sheathing is specified in the energy documentation, contractors should verify that the installed roof deck matches the approved project requirements.

What Is a Radiant Barrier in an attic

Where Is a Radiant Barrier Installed in an Attic?

The Installation Method Must Match the Approved Roof and Attic Design

A radiant barrier is typically associated with the upper portion of the attic rather than simply being laid over the attic-floor insulation.

The intended configuration needs to preserve the required relationship between:

  • The reflective surface
  • The roof structure
  • The attic air space
  • Ventilation openings

Does a Radiant Barrier Need to Cover the Entire Attic?

When a radiant barrier is being installed as part of an applicable California compliance design, coverage requirements matter.

Current California residential reference criteria specify coverage of gable-end walls and other vertical surfaces within the attic when the radiant barrier is part of the qualifying installation.

The goal is not simply to attach a few reflective sheets in isolated areas.

The installation needs to correspond to the qualifying design.

Why Are Gable Ends Important?

Gable-end walls form vertical attic surfaces that can participate in radiant heat exchange.

California installation criteria address these surfaces when a radiant barrier is required or modeled for applicable energy credit.

Leaving required areas uncovered can create a difference between:

  • The approved energy calculation
  • The intended radiant-barrier system
  • The actual field installation

That is why the contractor should follow the approved energy documentation rather than treating the radiant barrier as an optional decorative material.

Does Attic Ventilation Matter With a Radiant Barrier?

It can.

California’s current residential reference criteria include attic-ventilation provisions for applicable prescriptive radiant-barrier configurations.

The energy requirements can address:

  • Total ventilation area
  • Lower vents
  • Upper vents
  • Location of vents
  • Airflow around the radiant-barrier installation

The exact requirements depend on the project and compliance path.

A radiant barrier should therefore be coordinated with the complete attic design rather than treated as an isolated product.

Should the Radiant Barrier Block Attic Vents?

No installation should intentionally block ventilation openings that are required to remain functional.

The material may need to be cut or installed around vents so airflow can continue.

This is particularly important around:

  • Eave vents
  • Ridge vents
  • Gable vents
  • Other approved attic ventilation openings

Does Dust Affect a Radiant Barrier?

The effectiveness of a low-emittance surface depends in part on the exposed reflective surface remaining capable of performing as intended.

This is one reason installation orientation matters.

A radiant barrier installed horizontally with the reflective surface facing upward may collect dust differently from a downward-facing configuration.

California’s qualifying installation criteria specify the relevant installation arrangements rather than leaving orientation to guesswork.

Can a Radiant Barrier Be Installed in an Existing Attic?

Radiant barriers can be installed in some existing attic configurations, but installation conditions can differ from new construction.

Existing projects may need to consider:

  • Access
  • Existing rafters or trusses
  • Existing roof decking
  • Attic ventilation
  • Electrical wiring
  • Mechanical systems
  • Existing insulation

If the material is being added specifically to satisfy an energy-compliance requirement, the installation should be reviewed against the applicable code criteria and energy documentation.

What Is a Radiant Barrier under Title 24

How Does a Radiant Barrier Relate to Title 24?

Radiant Barrier Requirements Depend on the Project and Compliance Path

A radiant barrier can be relevant to California Title 24 energy compliance, particularly in residential roof-and-attic designs.

However:

A radiant barrier is not automatically required on every California building project.

Whether it appears in a project can depend on:

  • Building type
  • Climate zone
  • Roof and attic design
  • Prescriptive compliance path
  • Performance compliance path
  • Other envelope measures included in the design

This distinction is important because California contains 16 building climate zones and several different methods of demonstrating Energy Code compliance.

Is a Radiant Barrier Mandatory Everywhere in California?

No universal statement should be made that every California attic requires one.

The Energy Code has project-specific requirements and compliance paths.

A radiant barrier may be:

  • Required under an applicable prescriptive configuration
  • Included as a modeled measure in a performance approach
  • Unnecessary under another qualifying roof or attic configuration

The correct answer comes from reviewing the actual project and applicable Energy Code requirements.

Can a Radiant Barrier Be Used in Title 24 Performance Calculations?

Yes, when the installation satisfies the applicable eligibility criteria for modeling credit.

The current California residential reference criteria establish conditions a radiant barrier must meet before applicable approved compliance software can recognize the measure.

These include product and installation requirements.

Therefore, the calculation should not take credit for a radiant barrier that will not actually be installed in the qualifying manner.

What Happens if the Energy Report Includes a Radiant Barrier?

If the approved energy design relies on a radiant barrier, the construction should reflect that requirement.

The project team should verify that:

  • The radiant barrier is shown where needed
  • The product satisfies applicable requirements
  • The material is installed in the correct orientation
  • Applicable attic surfaces are covered
  • Required ventilation is maintained

Removing the radiant barrier after the energy calculation has been completed can change the assumptions used to demonstrate compliance.

Can I Remove the Radiant Barrier From My Title 24 Design?

Possibly, but the existing analysis should be reviewed first.

If the calculation relies on the radiant barrier as an energy-efficiency measure, removing it may require another compliance strategy.

That could potentially involve changes to:

  • Roof configuration
  • Insulation
  • Windows
  • HVAC efficiency
  • Other qualifying energy measures

Do not simply delete a required radiant-barrier note from the plans without determining whether the energy analysis needs revision.

Can I Add a Radiant Barrier to Improve the Calculation?

Potentially, when the project and compliance method allow the measure to receive applicable energy credit.

However, AES should evaluate the effect using the applicable compliance method rather than assuming the material will automatically solve a compliance problem.

Energy performance depends on the complete building design.

Does the Climate Zone Matter?

Yes.

California divides the state into 16 building climate zones because heating, cooling, temperature, and solar conditions vary significantly across the state.

Roof-and-attic requirements can therefore vary with climate and compliance strategy.

For additional project-specific background, review why Title 24 standards vary by climate zone.

The Current 2025 Energy Code Still Includes Radiant-Barrier Documentation

For applicable permit applications filed on or after January 1, 2026, California uses the 2025 Building Energy Efficiency Standards.

The California Energy Commission’s current single-family compliance documents include a specific installation form addressing:

  • Roofing
  • Ventilation
  • Radiant barriers

For official information, review the California Energy Commission 2025 single-family compliance documents.

What Is a Radiant Barrier for California energy compliance

Radiant Barriers Must Match the Title 24 Calculations and Plans

A Product Substitution Can Require Energy-Compliance Review

A Title 24 report should represent the building that will actually be constructed.

If the report assumes a radiant barrier but the architectural roof details do not show it, the permit documents can contain a conflict.

Likewise, if the plans specify a radiant barrier but the energy analysis assumes a different attic design, the documents should be coordinated.

What Should Be Shown on the Plans?

When a radiant barrier is part of the approved energy design, relevant plan information may include:

  • Radiant-barrier requirement
  • Roof or attic location
  • Applicable installation notes
  • Related insulation
  • Attic ventilation information

The exact plan notation depends on the project and design team.

Why Should the Contractor Review the Energy Report?

The contractor needs to understand which energy measures are part of the approved design.

Those measures can affect purchasing and installation decisions.

A contractor who changes the roof sheathing without checking the energy documents could unintentionally remove a specified radiant barrier.

Similarly, an apparently equivalent product may not have the same energy-compliance characteristics.

Can I Substitute Different Roof Sheathing?

Potentially, but the substitution should be checked when the original sheathing includes a radiant barrier relied upon by the energy design.

A replacement roof sheathing product that does not include the specified reflective surface may no longer correspond to the approved calculation.

What if My Contractor Already Installed Different Sheathing?

Contact the project designer and energy consultant before assuming the change is acceptable.

AES can review whether the Title 24 documentation needs to be revised.

The appropriate response depends on:

  • The approved energy analysis
  • The installed product
  • The roof assembly
  • The selected compliance path

Can a Radiant Barrier Cause a Plan-Check Correction?

It can become part of a correction when the plans and energy documentation do not agree.

Potential issues can include:

  • The energy report requires a radiant barrier but the plans omit it
  • The plans show a radiant barrier that is not reflected in the analysis
  • Installation notes are incomplete
  • The roof or attic configuration changed
  • Older calculations no longer match revised drawings

If the building department issues a correction, send AES the complete correction notice together with the latest plan set.

Does a Radiant Barrier Guarantee Title 24 Compliance?

No.

A radiant barrier is only one possible energy-related measure.

Title 24 compliance can depend on many building characteristics, including:

  • Climate zone
  • Building geometry
  • Windows
  • Insulation
  • Roof design
  • HVAC efficiency
  • Duct conditions
  • Ventilation
  • Water heating

Adding a radiant barrier does not automatically make a noncompliant design compliant.

The complete analysis needs to be evaluated.

What Is a Radiant Barrier compared with insulation and cool roofing

Radiant Barrier vs. Insulation and Cool Roofing

These Energy Measures Address Different Parts of Heat Transfer

Radiant barriers are often discussed together with insulation and cool roofs because all three relate to building heat gain.

They should not be treated as identical technologies.

Radiant Barrier vs. Attic Insulation

Attic insulation provides thermal resistance between conditioned space and the attic.

A radiant barrier reduces radiant heat transfer within the roof-and-attic environment.

A project can use both.

For example:

  • Ceiling insulation may resist conductive heat flow toward the living space
  • The radiant barrier may reduce radiant energy transferred from the roof toward the attic interior

The two measures perform different jobs.

Radiant Barrier vs. Cool Roof

A cool roof generally addresses solar energy at the exterior roofing surface through characteristics such as solar reflectance and thermal emittance.

A radiant barrier is typically located below the exterior roofing surface, within the roof or attic assembly.

Therefore:

  • A cool roof affects how the exterior roof interacts with solar energy
  • A radiant barrier affects radiant heat transfer within the roof-and-attic assembly

A project can potentially involve one or both measures depending on the applicable design.

Radiant Barrier vs. Roof Insulation

Roof insulation becomes part of the thermal resistance of the roof assembly.

A radiant barrier instead relies on a low-emittance surface facing an appropriate air space.

A radiant barrier should not automatically be assigned the role of required roof insulation.

Is More Reflective Always Better?

The energy-compliance question is not simply whether a material appears highly reflective.

The product must satisfy the applicable tested performance and installation criteria.

For Title 24 purposes, use documented product characteristics rather than visual appearance.

Does a Radiant Barrier Make a House Cooler?

A radiant barrier can reduce radiant heat transfer into an attic.

How much that affects indoor conditions or cooling demand depends on the complete building.

Factors include:

  • Climate
  • Roof exposure
  • Insulation
  • Air sealing
  • Duct location
  • HVAC operation
  • Building design

It should not be marketed as though one reflective layer guarantees a particular indoor temperature or utility-bill reduction.

Can a Radiant Barrier Help When Ducts Are in the Attic?

Reducing attic radiant heat transfer can be relevant when ducts or mechanical equipment are located within a hot attic.

However, duct energy performance also depends on:

  • Duct insulation
  • Duct leakage
  • Duct location
  • Airflow
  • Mechanical-system design

A radiant barrier does not replace applicable duct requirements.

What Is a Radiant Barrier for new homes ADUs additions and remodels

When Might a Project Include a Radiant Barrier?

New Homes, ADUs, Additions and Roof Changes Can Require Review

Whether a radiant barrier becomes part of a project depends on the construction and compliance strategy.

Projects that may need the issue reviewed include:

  • New homes
  • New detached ADUs
  • Large additions
  • Major residential remodels
  • Roof reconstruction
  • Projects changing attic configurations
  • Projects using performance-based Title 24 calculations

What About a New Home?

A new home involves a complete roof-and-envelope design.

The Title 24 analysis can evaluate:

  • Roof assemblies
  • Ceiling insulation
  • Attic configuration
  • Radiant barriers when applicable
  • Windows
  • Walls
  • HVAC
  • Duct locations

The final roof design should correspond to the approved energy analysis.

What About an ADU?

A new detached ADU can be analyzed as its own residential structure.

A radiant barrier may be one of the roof-and-attic measures relevant to the selected compliance design.

An attached ADU or conversion can involve different conditions.

For additional information, review ADU Title 24.

What About an Addition?

An addition can create new roof area and new conditioned space.

The new portion may have:

  • A new attic
  • New roof decking
  • New insulation
  • New windows
  • New or extended duct systems

The applicable energy requirements depend on the addition and selected compliance method.

What About a Remodel?

A remodel does not automatically require a radiant barrier simply because interior work is being performed.

The issue becomes more relevant when the project significantly alters:

  • The roof
  • The attic
  • The building envelope
  • Other energy-related components

The actual construction scope needs to be reviewed.

What About Reroofing?

Reroofing and roof reconstruction are not always the same project.

Replacing exterior roofing material does not necessarily mean the entire roof deck or attic assembly is being reconstructed.

If the project removes or changes roof sheathing, insulation, or other energy-related components, additional review may be appropriate.

Do not assume that every reroof requires a new radiant barrier or that no radiant-barrier requirement can apply.

What Information Does AES Need to Review a Radiant Barrier Question?

Useful project information can include:

  • Current floor plans
  • Roof plans
  • Building sections
  • Roof details
  • Attic configuration
  • Insulation specifications
  • Existing Title 24 report
  • Proposed roof sheathing
  • Building-department corrections

For a broader intake guide, review what AES will need from you.

What Is a Radiant Barrier and how Alternative Energy Systems can help

Need Help With a Radiant Barrier in Your Title 24 Design?

Review the Plans Before Changing the Roof or Attic Assembly

If the project already contains a Title 24 report, begin by checking whether a radiant barrier is included in the approved compliance design.

AES can review:

  • The existing energy report
  • Roof plans
  • Building sections
  • Insulation specifications
  • Proposed design changes

The goal is to determine whether the radiant barrier is simply an architectural choice or an energy measure being relied upon by the compliance analysis.

What if My Plans and Title 24 Report Do Not Match?

Resolve the discrepancy before construction whenever possible.

For example, the report may specify a radiant barrier while the roof detail shows conventional sheathing without one.

Alternatively, the plans may call for radiant-barrier sheathing while the energy analysis was prepared using another roof configuration.

Either situation should be reviewed.

What if the Building Department Requests More Information?

Send AES the complete correction notice together with:

  • The latest plans
  • The existing Title 24 report
  • Roof details
  • Any revised product specifications

AES can determine whether the comment involves:

  • Plan notation
  • A product specification
  • Installation details
  • The energy calculation
  • A broader roof-design revision

Should a Radiant Barrier Be Added Just to Pass Title 24?

The correct approach is to evaluate the complete design.

A radiant barrier may be one possible measure, but a consultant should not assume it is automatically the best or only solution.

Other project characteristics can influence compliance.

For more information about how these features are evaluated together, review Title 24 energy analysis and Title 24 energy calculations.

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides professional Title 24 energy calculations, compliance documentation, revisions, and energy-related plan-check support throughout California.

AES brings more than 30 years of California energy-compliance experience to:

  • New homes
  • ADUs
  • Garage conversions
  • Additions
  • Residential remodels
  • Multifamily projects
  • Mixed-use buildings
  • Commercial construction
  • Tenant improvements
  • Roof and envelope changes
  • Energy-related plan-check corrections

AES reviews the actual project plans and energy assumptions rather than treating every roof or attic as though it has the same compliance requirements.

Learn more on the About Us page or review company background on the clients page.

What Is a Radiant Barrier Title 24 assistance

Get Help Understanding Your Radiant Barrier Requirement

Call (626) 365-1518 | Alternative Energy Systems

Understanding What Is a Radiant Barrier begins with recognizing that it is a reflective building material designed to reduce radiant heat transfer, commonly within roof-and-attic assemblies.

It is not simply another name for insulation.

For California Title 24 projects, a radiant barrier can become part of the approved energy-compliance design when the applicable roof, climate zone, compliance path, and construction details call for it.

When it is used for compliance, the product and installation need to correspond to the applicable California requirements.

Alternative Energy Systems can review your:

  • Plans
  • Roof details
  • Title 24 report
  • Energy calculations
  • Building-department corrections

and determine whether the radiant barrier is part of the energy-compliance design or whether the documentation needs to be revised.

Call (626) 365-1518, email info@title24energy.com, or use the contact page to discuss the project.

When service and payment have already been arranged, payment can be completed through the AES payment page.

Frequently Asked Questions: What Is a Radiant Barrier?

What Is a Radiant Barrier?

A radiant barrier is a reflective, low-emittance building material designed to reduce radiant heat transfer. In residential construction, it is commonly installed as part of a roof-and-attic assembly.

How does a radiant barrier work?

It reduces radiant heat exchange between the heated roof assembly and surfaces within the attic.

Is a radiant barrier insulation?

It is an energy-control material, but it does not perform the same function as conventional bulk insulation. Insulation primarily resists conductive heat flow, while a radiant barrier reduces radiant heat transfer.

Can a radiant barrier replace attic insulation?

Do not assume so. Applicable ceiling or roof insulation requirements remain separate from radiant-barrier requirements.

Where is a radiant barrier installed?

Common qualifying installations can place the material at or below roof decking or around roof trusses and rafters, depending on the approved installation method.

Which way should a radiant barrier face?

For the California attic configurations addressed by current residential criteria, the low-emittance reflective side is generally oriented downward toward the attic interior.

Does a radiant barrier need an air space?

The qualifying installation depends on the reflective surface interacting with an air space. Specific spacing requirements depend on the installation method.

What emittance does California require?

For applicable current residential Energy Code eligibility, the radiant barrier must have an emittance of 0.05 or less using the specified test methods.

Does a radiant barrier need to cover gable ends?

Current California residential criteria require applicable radiant-barrier installations to cover gable-end walls and other vertical attic surfaces.

Does every California home require a radiant barrier?

No. Applicability depends on the project, climate zone, attic design, and compliance method.

Does Title 24 require radiant barriers?

Title 24 can require or recognize radiant barriers under applicable residential roof-and-attic compliance configurations, but they are not universally required on every project.

Can a radiant barrier receive energy-compliance credit?

Yes, when the product and installation meet the applicable eligibility requirements for the selected compliance method.

Does the 2025 Energy Code still address radiant barriers?

Yes. Current California residential compliance documents and reference criteria include radiant-barrier provisions.

Does climate zone affect whether one is needed?

It can. California Energy Code requirements vary according to climate zone, building type, roof design, and compliance approach.

Is radiant-barrier roof sheathing acceptable?

Factory-laminated radiant-barrier roof sheathing can be used when the product and installation satisfy the applicable requirements.

Can a radiant barrier be installed in an existing attic?

It can be installed in some existing attic conditions, but the product and installation need to be appropriate for the existing structure and intended purpose.

Can I install foil directly on top of attic insulation?

Do not assume that placing reflective material anywhere in the attic creates a qualifying radiant-barrier installation. The installation needs to satisfy applicable product, orientation, air-space, and coverage requirements.

Does attic ventilation matter?

Yes, ventilation can be part of the applicable prescriptive roof-and-attic configuration and should not be obstructed by the radiant barrier.

Does a radiant barrier block heat completely?

No. It reduces radiant heat transfer but does not eliminate conduction, convection, or every source of building heat gain.

Will a radiant barrier guarantee lower utility bills?

No specific savings should be guaranteed. Actual building energy use depends on climate, envelope construction, HVAC systems, occupant behavior, and many other variables.

Is a radiant barrier the same as a cool roof?

No. A cool roof addresses solar performance at the exterior roof surface, while a radiant barrier typically reduces radiant heat transfer within the roof-and-attic assembly.

Can I remove a radiant barrier shown on my Title 24 report?

Have the energy analysis reviewed first. If compliance relies on the radiant barrier, removing it can require revised calculations or another qualifying design measure.

Can I substitute regular roof sheathing for radiant-barrier sheathing?

The substitution should be reviewed if the approved energy design specifies radiant-barrier sheathing.

What if the contractor already changed the roof sheathing?

Provide the installed product information and current plans to AES so the effect on the existing energy documentation can be evaluated.

Can a missing radiant barrier cause a plan-check issue?

Yes, particularly when the energy report requires it but the architectural drawings do not show a corresponding requirement.

Can a radiant barrier make an otherwise noncompliant project pass?

It may contribute to a compliant energy design when applicable, but compliance depends on the complete project rather than one building feature.

What should I send AES for review?

Current plans, roof plans, building sections, roof details, insulation specifications, the existing Title 24 report, and any building-department corrections are useful starting documents.

How do I get help with a radiant barrier requirement?

Call Alternative Energy Systems at (626) 365-1518 and provide the current plans and available energy documentation for review.

How Long Does It Take to Prepare Title 24 Calculations?

How Long Does It Take to Prepare Title 24 Calculations

How Long Does It Take to Prepare Title 24 Calculations?

Call (626) 365-1518 | Alternative Energy Systems

How Long Does It Take to Prepare Title 24 Calculations depends on the project, the completeness of the construction plans, the building systems involved, and whether design questions need to be resolved before the energy analysis can be finalized.

There is no single preparation time that accurately applies to every California project.

A straightforward project with coordinated drawings and complete specifications can generally move through the calculation process more efficiently than a project involving:

  • Incomplete plans
  • Missing window specifications
  • Unclear insulation assemblies
  • Undecided HVAC equipment
  • Conflicting floor areas
  • Several mechanical systems
  • Complex building geometry
  • Commercial lighting calculations
  • Multiple design revisions
  • Existing plan-check corrections

The preparation process can include much more than entering square footage into software.

Alternative Energy Systems may need to:

  • Review the project scope
  • Study the construction plans
  • Identify conditioned and unconditioned areas
  • Review windows and exterior doors
  • Review wall, roof, ceiling, and floor assemblies
  • Review HVAC equipment and ducts
  • Review ventilation
  • Review water-heating information
  • Review commercial lighting when applicable
  • Identify missing or conflicting information
  • Complete the applicable energy analysis
  • Evaluate whether the proposed design complies
  • Prepare the applicable compliance documentation
  • Coordinate the results with the plans

AES brings more than 30 years of California energy-compliance experience to residential, multifamily, mixed-use, and commercial construction.

To discuss the preparation schedule for a specific project, call (626) 365-1518 and provide the most current plans available.

There Is No Universal Preparation Time for Every Project

Title 24 calculations are project-specific.

Two buildings can have similar square footage but require very different amounts of calculation and review time.

For example, one project might contain:

  • A simple rectangular floor plan
  • One roof configuration
  • A complete window schedule
  • One HVAC system
  • Clearly identified insulation

Another project of approximately the same size might contain:

  • Several roof elevations
  • Multiple wall assemblies
  • Extensive glazing
  • Several HVAC systems
  • Existing and proposed construction
  • Missing equipment specifications

The second project can require substantially more review and coordination even though its floor area is similar.

Preparation Time Begins With Understanding the Actual Project

Before meaningful calculations can be completed, AES needs to understand what is being built.

The project may involve:

  • A new home
  • An ADU
  • A garage conversion
  • An addition
  • A residential remodel
  • A multifamily project
  • A mixed-use building
  • A commercial building
  • A tenant improvement
  • An HVAC project
  • A commercial lighting project

That classification affects which information needs to be reviewed and which compliance method may apply.

Title 24 Calculation Preparation Is Different From Permit Review

Preparation time refers to the work needed to evaluate the project and prepare the applicable energy-compliance documentation.

That is different from:

  • Building-department intake
  • Plan-check scheduling
  • Plan-review turnaround
  • Correction cycles
  • Permit issuance

Those later steps are controlled by the applicable enforcement agency.

This page focuses specifically on the time required to prepare the energy calculations themselves.

How Long Does It Take to Prepare Title 24 Calculations with complete plans

What Actually Controls the Preparation Time?

Complete Plans Usually Allow the Calculations to Move Faster

One of the biggest factors is the quality and completeness of the information provided at the beginning.

Useful project documents can include:

  • Floor plans
  • Exterior elevations
  • Building sections
  • Roof plans
  • Window schedules
  • Exterior-door information
  • Insulation details
  • HVAC specifications
  • Duct-location information
  • Ventilation information
  • Water-heating specifications
  • Commercial lighting plans when applicable

When those documents agree with one another, AES can spend more time performing the analysis and less time resolving basic project discrepancies.

For a complete intake overview, review what AES will need from you.

Floor Plans Affect How Quickly the Building Can Be Modeled

Floor plans can establish:

  • Conditioned floor area
  • Room configuration
  • Exterior wall lengths
  • Windows
  • Doors
  • Existing construction
  • Proposed construction

If the floor area differs among sheets or the proposed work is unclear, calculation work may need to pause until the correct scope is confirmed.

Elevations Help Confirm Exterior Conditions

Exterior elevations can help verify:

  • Window locations
  • Window quantities
  • Exterior doors
  • Roof configuration
  • Building height
  • Other envelope characteristics

When floor plans and elevations disagree, AES may need clarification before completing the final model.

Building Sections Can Prevent Assumptions

Sections are often important for understanding:

  • Wall assemblies
  • Roof assemblies
  • Ceiling construction
  • Attic conditions
  • Floor conditions
  • Insulation locations

Projects with vaulted ceilings, multiple roof configurations, garage conversions, or second-story additions can require additional attention.

Window Information Is a Common Timing Factor

Windows can influence the analysis through:

  • Quantity
  • Size
  • Orientation
  • U-factor
  • Solar heat gain coefficient

If the drawings show windows but the performance specifications have not been determined, final calculations may need to wait for clarification.

Insulation Details Need to Be Consistent

The analysis may need insulation information for:

  • Walls
  • Roofs
  • Ceilings
  • Attics
  • Floors

When insulation notes conflict with the building sections, AES needs to determine which construction assembly is actually proposed.

HVAC Information Can Determine Whether the Calculation Is Ready to Finish

Mechanical inputs can include:

  • System type
  • Heating efficiency
  • Cooling efficiency
  • Heat-pump configuration
  • Number of systems
  • Duct locations
  • Ventilation

If the mechanical design remains undecided, preliminary work may continue, but final calculations may require additional information.

How Long Does It Take to Prepare Title 24 Calculations for residential projects

How Project Type Changes the Preparation Timeline

Residential, ADU, Addition and Remodel Calculations Are Not Identical

A small alteration and a complete new residence do not require the same amount of analysis.

The amount of work depends on which portions of the building must be evaluated.

How Long Do Calculations Take for a New Home?

New residential construction can require analysis of the complete proposed building.

That can include:

  • Building geometry
  • Orientation
  • Climate zone
  • Walls
  • Roofs
  • Ceilings
  • Floors
  • Windows
  • Insulation
  • HVAC systems
  • Ducts
  • Ventilation
  • Water heating

A straightforward new home with complete plans can be easier to analyze than a highly customized design with complicated geometry and unresolved product selections.

How Long Do Calculations Take for an ADU?

ADU preparation time depends partly on what kind of ADU is being created.

The project might be:

  • A new detached ADU
  • An attached ADU
  • A garage conversion
  • A conversion of existing living space

A detached ADU can require analysis of an entire new residential structure.

A conversion can require additional attention to the difference between existing and proposed construction.

For additional project information, review ADU Title 24.

How Long Do Calculations Take for a Garage Conversion?

A garage conversion can require review of:

  • Existing walls
  • New insulation
  • Roof or ceiling construction
  • Floor conditions
  • New windows
  • HVAC
  • Ventilation

The calculation process is generally easier when the plans clearly separate existing construction from the proposed living space.

How Long Do Calculations Take for an Addition?

An addition may be relatively simple or highly involved.

Preparation time can depend on:

  • New conditioned floor area
  • Building geometry
  • New windows
  • Roof design
  • Insulation
  • HVAC changes
  • Duct extensions
  • Relationship to the existing structure

Some additions can use applicable prescriptive documentation, while other designs may use performance calculations.

The required compliance method can affect the amount of preparation work.

How Long Do Calculations Take for a Remodel?

The answer depends on what the remodel changes.

A project involving only limited energy-related alterations can require a different scope from a major whole-house renovation involving:

  • Windows
  • Walls
  • Insulation
  • Roofing
  • HVAC
  • Ducts
  • Water heating

The word “remodel” by itself does not establish the calculation workload.

The Compliance Method Can Affect Preparation Time

California energy compliance can involve a prescriptive approach or performance analysis.

A prescriptive project follows applicable component and system requirements.

A performance project can involve computer modeling of the proposed design.

Performance modeling can require detailed information involving:

  • Building geometry
  • Orientation
  • Envelope assemblies
  • Windows
  • Mechanical systems
  • Other applicable energy inputs

For more information, review Title 24 energy calculations.

How Long Does It Take to Prepare Title 24 Calculations for commercial and multifamily projects

Commercial and Multifamily Calculations Can Require More Coordination

More Building Systems Can Mean More Information to Review

Commercial and multifamily projects can involve information from several design disciplines.

That can include:

  • Architectural drawings
  • Mechanical drawings
  • Electrical drawings
  • Lighting schedules
  • Lighting-control plans
  • Ventilation information
  • Water-heating information
  • Envelope specifications

The calculation work can move efficiently when those documents are coordinated.

It can take longer when the architectural, mechanical, and electrical information describe different versions of the project.

Commercial Lighting Can Add Preparation Work

Applicable nonresidential projects can require review of:

  • Fixture types
  • Fixture quantities
  • Fixture wattage
  • Space use
  • Lighting power
  • Occupancy controls
  • Automatic shutoff controls
  • Daylighting controls
  • Exterior lighting

If the lighting schedule is still under development, the energy analysis may need to wait for final information.

Commercial Mechanical Systems Can Also Increase Complexity

Commercial projects can include several systems or serving zones.

AES may need to review:

  • Equipment schedules
  • System types
  • Equipment efficiency
  • Ventilation
  • Controls
  • Other applicable mechanical information

Several unresolved systems can add more coordination time than a project with one clearly defined mechanical design.

Multifamily Projects Can Combine Residential and Common-Area Information

Multifamily calculations may involve:

  • Dwelling units
  • Common areas
  • Central mechanical equipment
  • Individual mechanical equipment
  • Central water heating
  • Individual water heating
  • Common-area lighting
  • Multiple envelope conditions

The amount of preparation work depends on the actual building and systems rather than simply the number of units.

Tenant Improvements Can Be Fast or Complex Depending on Scope

A commercial tenant improvement may involve only a limited set of regulated systems.

Another tenant improvement may include:

  • New lighting
  • New lighting controls
  • Mechanical changes
  • Ventilation changes
  • Water heating
  • Storefront glazing

The calculation timeline should therefore be based on the actual tenant-improvement scope.

For related services, review Title 24 compliance services.

What Happens During the Calculation Process?

Preparing the calculations generally involves several stages.

1. Project Scope Review

AES first identifies what the project includes and what documentation may apply.

2. Plan and Specification Review

The construction documents are reviewed for energy-related information.

3. Missing Information Review

Unclear or missing inputs are identified.

4. Energy Analysis

The project is evaluated using the applicable compliance method.

5. Compliance Review

If the proposed design does not satisfy the applicable requirements, potential design adjustments may need to be discussed.

6. Compliance Documentation

Applicable forms and calculation results are prepared.

7. Plan Coordination

The energy measures are checked against the current construction documents.

This process is one reason preparation time can vary among projects.

For broader background about the standards themselves, review the California Energy Code overview on Wikipedia.

The Current Code Cycle Can Matter

For applicable permit applications filed on or after January 1, 2026, California uses the 2025 Building Energy Efficiency Standards.

When performance compliance is used, the project must use software approved for the applicable current code cycle, occupancy, and project scope.

For official current information, review the California Energy Commission 2025 Energy Code Compliance Software page.

How Long Does It Take to Prepare Title 24 Calculations when information is missing

What Commonly Delays Title 24 Calculations?

Missing Information and Design Changes Can Extend Preparation Time

In many cases, the calculations themselves are not the only thing affecting the schedule.

The work may be waiting for information needed to complete them accurately.

Common examples include:

  • Missing floor-area information
  • Conflicting plan dimensions
  • Incomplete window schedules
  • Missing window-performance values
  • Unclear wall insulation
  • Missing roof details
  • Undecided HVAC equipment
  • Unknown duct locations
  • Incomplete water-heating information
  • Incomplete commercial lighting schedules

Providing accurate information earlier can help reduce unnecessary stops in the calculation process.

Conflicting Plans Can Cause More Delay Than Missing Plans

An obvious missing item can be easy to identify.

Conflicting information can be more difficult because AES needs to determine which version is correct.

Examples include:

  • One floor area on the cover sheet and another on the floor plan
  • Different windows shown on the elevation and schedule
  • Different insulation values on separate sheets
  • Different HVAC systems shown by the architect and mechanical designer

The calculation should not be finalized until the project information is reasonably coordinated.

Undecided Windows Can Hold Up Final Results

Window performance can materially affect the energy analysis.

If U-factor or solar heat gain coefficient values remain undecided, AES may not be able to finalize the calculation using the actual intended design.

Undecided HVAC Equipment Can Also Hold Up Completion

The calculation can depend on:

  • System type
  • Efficiency
  • Heat-pump configuration
  • Duct conditions

A mechanical design that changes repeatedly can lead to repeated calculation updates.

Design Changes During the Analysis Can Extend the Timeline

A project may begin with one design and change while the energy analysis is underway.

Changes to the following can require portions of the model to be revised:

  • Conditioned floor area
  • Room layout
  • Windows
  • Insulation
  • Roof construction
  • HVAC equipment
  • Duct configuration
  • Water heating
  • Commercial lighting

The larger the design change, the more recalculation may be necessary.

What if the First Calculation Does Not Comply?

A performance analysis may indicate that the proposed configuration needs adjustment before final documentation can be completed.

Possible areas for review can include:

  • Window performance
  • Window area
  • Insulation
  • Roof characteristics
  • HVAC efficiency
  • Other qualifying energy measures

The project team may need to decide which adjustment works best for the design.

That decision-making process can add time even when the original calculations were completed promptly.

Waiting for Client or Designer Decisions Can Affect Completion

Sometimes the energy consultant is waiting for an answer rather than performing calculations.

Examples include:

  • Which window product will be used?
  • Which HVAC system is being installed?
  • Which insulation assembly is correct?
  • Which floor-area figure is current?
  • Which lighting fixture schedule should be modeled?

Prompt clarification can help keep the project moving.

Revision Requests Can Add Additional Preparation Time

Revision timing depends on what changed.

Updating one specification is different from:

  • Changing the building footprint
  • Adding conditioned space
  • Redesigning multiple windows
  • Changing the roof
  • Changing the mechanical design
  • Revising an entire commercial lighting plan

The project-specific scope controls the amount of additional work.

How Long Does It Take to Prepare Title 24 Calculations versus building department review

Preparation Time Is Not the Same as Building Department Review Time

AES Prepares the Calculations, While the Jurisdiction Controls Plan Check

This distinction is important when planning a project schedule.

Title 24 preparation can involve:

  • Plan review
  • Calculation preparation
  • Compliance analysis
  • Form preparation
  • Energy-related plan coordination

After the permit package is submitted, the building department controls its own review process.

That can include:

  • Application intake
  • Plan-check assignment
  • Review scheduling
  • Correction comments
  • Resubmittal review
  • Permit issuance

AES cannot guarantee how quickly a particular city, county, or other enforcement agency will complete plan review.

A Finished Calculation Does Not Mean the Permit Is Finished

Energy calculations support one portion of the permit package.

The project may still be reviewed for:

  • Architectural requirements
  • Structural requirements
  • Mechanical requirements
  • Electrical requirements
  • Plumbing requirements
  • CALGreen
  • Fire and life-safety requirements
  • Other applicable building standards

Completion of the energy calculations does not guarantee permit approval.

Plan-Check Corrections Can Require New Calculation Work

If the building department issues energy-related comments, send AES:

  • The complete correction notice
  • The latest architectural plans
  • The existing energy calculations
  • Updated mechanical information
  • Updated electrical or lighting information when applicable
  • Updated product specifications

The correction may involve:

  • A clarification
  • A missing form
  • Updated calculations
  • Revised specifications
  • Coordination between the report and plans

The amount of preparation time depends on what the correction actually requires.

Sending the Entire Correction Notice Can Save Time

A single isolated correction comment may not show enough context.

The complete notice can help AES determine whether the issue belongs to:

  • The energy calculations
  • The architectural plans
  • The mechanical plans
  • The lighting plans
  • Another part of the permit package

That can reduce unnecessary back-and-forth.

Can Calculations Begin Before Plans Are Final?

Yes, preliminary review can often begin earlier.

This can help identify missing energy-related information while the design is still being developed.

However, final calculations require enough information to accurately represent the project.

If the plans are likely to change substantially, completing the final model too early can create additional revision work.

When Should I Request the Calculations?

A practical time to begin is when the design is developed enough to establish:

  • Building size
  • Basic geometry
  • Window configuration
  • Envelope assemblies
  • Mechanical approach

Waiting until immediately before permit submission can leave little time to resolve energy-related design questions.

Can Early Review Make the Process Faster?

It can help reduce avoidable delays.

Early review gives the project team time to address issues involving:

  • Windows
  • Insulation
  • Roof assemblies
  • HVAC
  • Water heating
  • Commercial lighting

before the construction documents are considered final.

How Can I Help the Calculations Move More Efficiently?

Several simple steps can improve the process:

  • Send the latest plans
  • Do not mix sheets from different revision dates
  • Clearly identify existing and proposed work
  • Include elevations and sections
  • Include available window information
  • Identify insulation assemblies
  • Provide available HVAC information
  • Identify duct locations when known
  • Provide water-heating information
  • Provide commercial lighting schedules when applicable
  • Send complete plan-check comments
  • Notify AES promptly when the design changes

For a detailed intake guide, review what AES will need from you.

Do I Need Every Product Selected Before Starting?

Not necessarily.

AES may be able to begin with available design information.

Final calculations still need sufficient information to represent the intended project accurately.

Waiting for every manufacturer and model number may not always be necessary at the preliminary stage, but unresolved performance inputs can prevent finalization.

What Is the Difference Between Preliminary Review and Final Calculations?

Preliminary review can help identify:

  • Missing information
  • Potential conflicts
  • Important energy-related design decisions

Final calculations establish the energy-compliance analysis using the project information intended for permit submission.

The closer the preliminary information is to the final design, the fewer revisions may be necessary.

How Long Do Revisions Take?

There is no universal revision time.

A small revision may involve one limited change.

A larger revision may require:

  • Rebuilding portions of the model
  • Changing glazing
  • Changing envelope assemblies
  • Changing HVAC systems
  • Revising forms
  • Recoordinating the report with new plans

Revision time therefore depends on the extent of the design change.

Can an Old Title 24 Model Save Preparation Time?

An older report or model can sometimes provide useful background.

However, it should not automatically be treated as current.

AES still needs to compare it with:

  • The current plans
  • The current project scope
  • The applicable Energy Code cycle
  • Current windows
  • Current insulation
  • Current mechanical systems

If the project has changed significantly, the old analysis may provide limited value.

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides professional Title 24 calculations, energy-compliance documentation, revisions, and energy-related plan-check support throughout California.

AES brings more than 30 years of California energy-compliance experience to:

  • New residential construction
  • ADUs
  • Garage conversions
  • Additions
  • Residential remodels
  • Multifamily projects
  • Mixed-use projects
  • Commercial buildings
  • Office tenant improvements
  • Retail improvements
  • Restaurant projects
  • Warehouse alterations
  • HVAC projects
  • Commercial lighting projects
  • Energy-related plan-check corrections

AES reviews the actual project rather than assigning every building the same assumed preparation time.

Learn more through the About Us page or review company background on the clients page.

How Long Does It Take to Prepare Title 24 Calculations project specific turnaround

Get a Project-Specific Title 24 Calculation Schedule

Call (626) 365-1518 | Alternative Energy Systems

The best answer to How Long Does It Take to Prepare Title 24 Calculations comes from reviewing the actual project.

Preparation time depends on:

  • Project type
  • Building size
  • Building complexity
  • Plan completeness
  • Window information
  • Envelope details
  • HVAC information
  • Water heating
  • Commercial lighting when applicable
  • Selected compliance method
  • Design changes
  • Revisions

A complete, coordinated project can generally be prepared more efficiently than one where important information is still changing.

Alternative Energy Systems can review your current plans, identify what information is still needed, and discuss a project-specific preparation schedule.

Call (626) 365-1518, email info@title24energy.com, or begin through the contact page.

When service and payment have already been arranged, payment can be completed through the AES payment page.

Frequently Asked Questions: How Long Does It Take to Prepare Title 24 Calculations?

How Long Does It Take to Prepare Title 24 Calculations?

There is no universal preparation time. The schedule depends on project type, size, complexity, plan completeness, available specifications, design questions, and revisions.

Can AES give me an exact preparation time without seeing the project?

A meaningful project-specific estimate requires understanding the project scope and available plans first.

Do complete plans make the calculations faster?

Complete and coordinated plans can help the process move more efficiently because fewer project details need clarification.

Can incomplete plans still be reviewed?

Yes. Preliminary review can often begin with available information, but missing inputs can prevent the final calculations from being completed.

What information most commonly causes delays?

Incomplete window schedules, missing window-performance values, unclear insulation, missing roof details, undecided HVAC equipment, unknown duct locations, and incomplete commercial lighting information can all affect preparation time.

Can conflicting plans delay calculations?

Yes. AES may need clarification when different sheets show different floor areas, windows, insulation, or mechanical systems.

Do windows affect preparation time?

They can. Window quantity, size, orientation, U-factor, and solar heat gain coefficient may be needed for the applicable analysis.

Does HVAC selection affect preparation time?

Yes. Equipment type, efficiency, system configuration, ducts, and ventilation can affect the analysis.

Can calculations start before HVAC equipment is finalized?

Preliminary work may be possible, but final calculations need enough mechanical information to accurately represent the proposed design.

Do new homes take longer than additions?

Not automatically. New homes generally involve the complete building, while an addition may have a smaller scope but can still be complicated by existing conditions.

Do ADUs all take the same amount of time?

No. A detached ADU, attached ADU, garage conversion, and other conversion can require different analysis and plan review.

Do garage conversions require extra review?

They can because AES may need to distinguish existing unconditioned construction from the proposed conditioned living space.

Do commercial calculations take longer?

Commercial projects can involve additional lighting, controls, mechanical, ventilation, and other system information, but the actual preparation time depends on the project.

Do multifamily calculations take longer?

They can involve multiple units, common areas, central systems, individual systems, and other coordinated information. The actual timeline depends on the building.

Does performance modeling take longer than prescriptive compliance?

The scopes are different. Performance modeling can require detailed building inputs and iterative analysis, while prescriptive compliance follows applicable component and system requirements.

What happens if the first calculation does not comply?

The project team may need to evaluate design adjustments before the final compliance documentation is completed.

Can design changes extend preparation time?

Yes. Changes to floor area, windows, insulation, roof construction, HVAC, ducts, water heating, or commercial lighting can require recalculation.

How long does a revision take?

Revision time depends on the extent of the change. A small product update is different from redesigning a substantial portion of the project.

Are building-department corrections part of the original calculation time?

Plan-check corrections occur later in the permit process. If corrections require revised energy work, additional calculation preparation may be necessary.

Is building-department review included in the Title 24 calculation timeline?

No. Calculation preparation and building-department plan review are separate timelines.

Can AES guarantee when the building department will approve my plans?

No. The enforcement agency controls its own review and permit schedule.

Does completion of the calculations guarantee permit approval?

No. Energy compliance is one part of the complete building-permit review.

Can early Title 24 review save time later?

Early review can help identify missing information and design conflicts before the construction documents are considered final.

Should I wait until the plans are completely finished?

Not necessarily. Preliminary review can often begin earlier, although final calculations require enough information to represent the proposed design accurately.

What should I send first?

Current floor plans, elevations, sections, roof plans, window information, insulation details, HVAC information, water-heating specifications, commercial lighting information when applicable, and existing correction comments are useful starting documents.

What Energy Code is currently in effect?

For applicable permit applications filed on or after January 1, 2026, California uses the 2025 Building Energy Efficiency Standards.

How do I get a preparation-time estimate?

Call Alternative Energy Systems at (626) 365-1518 and provide the most current project plans and available specifications for review.

What Information Is Needed for Title 24 Calculations?

What Information Is Needed for Title 24 Calculations

What Information Is Needed for Title 24 Calculations?

Call (626) 365-1518 | Alternative Energy Systems

What Information Is Needed for Title 24 Calculations depends on the type of project, the construction scope, the building systems involved, and how complete the design is when the energy analysis begins.

For many projects, the best starting point is the most current set of construction plans available.

Those plans can help establish:

  • Building size
  • Conditioned floor area
  • Building configuration
  • Exterior walls
  • Roof and ceiling assemblies
  • Windows and exterior doors
  • Insulation
  • HVAC systems
  • Duct locations
  • Ventilation
  • Water heating
  • Commercial lighting when applicable

Not every project needs every document before AES can begin reviewing it.

A preliminary review can often identify what information is already usable, what is missing, and which decisions need to be finalized before the calculations and compliance forms can be completed.

Alternative Energy Systems brings more than 30 years of California energy-compliance experience to residential, multifamily, mixed-use, and commercial construction.

Call (626) 365-1518 or use the contact page to send available project information for review.

Start With the Current Plan Set

The most useful starting point is generally the latest version of the architectural or construction drawings.

That may include:

  • Floor plans
  • Exterior elevations
  • Building sections
  • Roof plans
  • Window schedules
  • Exterior-door schedules
  • Insulation notes
  • Mechanical plans or specifications
  • Water-heating information
  • Commercial lighting plans when applicable

Using the current drawings is important because energy calculations should represent the project that is actually being submitted and built.

An older set of plans can produce a report that no longer matches:

  • Floor area
  • Window sizes
  • Insulation
  • Roof configuration
  • HVAC equipment
  • Water heating

For more background about the governing standards, review the California Energy Code overview on Wikipedia.

Floor Plans Are Usually One of the Most Important Documents

Floor plans help establish the basic geometry of the project.

They can show:

  • Room layout
  • Exterior walls
  • Interior spaces
  • Conditioned areas
  • Unconditioned areas
  • Doors
  • Windows
  • Additions
  • Existing and proposed construction

For additions, garage conversions, ADUs, and remodels, it is especially helpful when the drawings clearly distinguish between existing work and proposed construction.

A calculation based on unclear building geometry can lead to unnecessary questions or revisions later.

Exterior Elevations Help Confirm Windows and Building Geometry

Elevations help AES understand how the building looks from each side.

They can be useful for confirming:

  • Window placement
  • Window quantity
  • Exterior doors
  • Building height
  • Roof configuration
  • Wall areas
  • Architectural changes

Floor plans and elevations should agree.

If a window appears on an elevation but not on the floor plan or window schedule, that inconsistency may need to be resolved before the final analysis is completed.

Building Sections Help Explain the Envelope

Building sections can show information that may not be obvious from a floor plan.

Useful details can include:

  • Wall construction
  • Ceiling construction
  • Roof assemblies
  • Attic conditions
  • Floor assemblies
  • Insulation locations
  • Relationship between conditioned and unconditioned spaces

Sections become particularly useful when a project includes:

  • Vaulted ceilings
  • Multiple roof types
  • Second-story additions
  • Garage conversions
  • Complex wall assemblies

What Information Is Needed for Title 24 Calculations floor plans elevations and sections

Roof Plans and Roof Assemblies Can Be Important

The roof can affect the energy analysis through its:

  • Area
  • Slope
  • Insulation
  • Ceiling configuration
  • Attic configuration
  • Roofing characteristics

If the project contains several roof conditions, the drawings should clearly identify which construction applies in each area.

For example, one part of a home might have an attic while another uses a vaulted ceiling.

Those conditions may need to be treated differently in the analysis.

Window Schedules Are Especially Important

Window information is one of the most common items needed to complete energy calculations accurately.

Useful information can include:

  • Window size
  • Window quantity
  • Window location
  • U-factor
  • Solar heat gain coefficient
  • Glazed exterior-door information

Window manufacturer specifications can also be helpful when they are available.

The energy report should correspond to the products or performance values that will actually appear in the permit documents.

Do I Need the Exact Window Manufacturer Before Starting?

Not always.

AES may be able to begin the review before the final manufacturer and model have been selected.

However, enough window-performance information needs to be available before the final calculations are completed.

The important point is to avoid finalizing the analysis around one window specification and then ordering a product with different performance values without reviewing the change.

What if My Window Schedule Is Incomplete?

Send the plans anyway.

AES can review what is available and identify the missing information.

An incomplete schedule may need clarification when:

  • Window sizes are missing
  • Elevations and schedules disagree
  • Performance values are not identified
  • Exterior glazed doors are not listed

Resolving those items earlier can reduce revisions later.

Insulation Information Is Needed for the Building Envelope

The plans should identify applicable insulation associated with:

  • Exterior walls
  • Roofs
  • Ceilings
  • Attics
  • Floors
  • Other thermal-envelope assemblies

The insulation notes should also be consistent with the building sections.

If one sheet identifies one assembly while another shows something different, AES may need clarification before finalizing the analysis.

What Information Is Needed for Title 24 Calculations windows insulation and roof details

HVAC Information Can Be Required Before Final Calculations

Mechanical information can have a significant effect on the energy analysis.

Depending on the project, helpful HVAC information may include:

  • Heating-system type
  • Cooling-system type
  • Heat-pump configuration
  • Equipment efficiency
  • Number of systems
  • Equipment specifications
  • Duct location
  • Ventilation information

If the HVAC equipment has not yet been selected, AES can identify what information will eventually be needed.

Duct Location Can Matter

The plans or mechanical information should identify where ducts are expected to be located when that information affects the analysis.

Potential locations can include:

  • Conditioned space
  • Attics
  • Crawlspaces
  • Garages
  • Other unconditioned areas

Duct-related information can also affect applicable field-verification requirements.

The energy report can identify applicable verification measures, but the report itself does not replace required field testing.

Ventilation Information May Be Needed

Depending on the project, ventilation information can include:

  • Whole-building ventilation
  • Local exhaust
  • Mechanical ventilation equipment
  • Outdoor-air information for commercial projects

Mechanical and architectural information should be coordinated so that the energy documentation reflects the actual proposed system.

Water-Heating Information Is Another Common Requirement

Useful water-heating information can include:

  • Equipment type
  • Energy source
  • Equipment efficiency
  • Heat-pump water-heater information
  • Central or individual systems

The amount of information needed depends on whether the project is residential, multifamily, or commercial.

Changing the water-heating system after the report is completed can require a review of the existing calculations.

Do I Need Final Equipment Model Numbers Before AES Can Start?

Not necessarily.

A preliminary review can often begin with the system type and available specifications.

Final calculations need enough information to represent the actual proposed design accurately.

If equipment changes later, AES can determine whether the report needs to be revised.

What Information Is Needed for Title 24 Calculations HVAC ducts ventilation and water heating

Commercial Projects Usually Need Additional Information

Commercial and nonresidential projects can require information from several design disciplines.

Depending on the scope, AES may need:

  • Architectural plans
  • Mechanical plans
  • Electrical plans
  • Lighting fixture schedules
  • Lighting-control information
  • Ventilation information
  • Service water-heating information
  • Envelope details

Commercial projects can include:

  • Office tenant improvements
  • Retail build-outs
  • Restaurant improvements
  • Warehouse alterations
  • Mixed-use projects
  • Commercial HVAC replacements
  • Interior lighting upgrades
  • Exterior lighting upgrades
  • New nonresidential buildings

For related professional assistance, review Title 24 compliance services and Title 24 energy analysis.

Commercial Lighting Plans Can Be Necessary

When the project affects commercial lighting, useful information can include:

  • Fixture types
  • Fixture quantities
  • Fixture wattage
  • Room or space use
  • Lighting-control plans
  • Occupancy controls
  • Daylighting controls
  • Exterior lighting when applicable

The electrical drawings and lighting schedules should be consistent.

If fixtures are changed during design, updated information may need to be reflected in the energy documentation.

Mechanical Plans Are Especially Helpful on Commercial Projects

Commercial mechanical systems can involve more than one piece of equipment or serving zone.

Helpful information can include:

  • Equipment schedules
  • System types
  • Equipment efficiency
  • Ventilation
  • Controls
  • Other applicable mechanical information

Conflicts between the architectural and mechanical plans can delay final calculations until the project team confirms which design is current.

Multifamily Projects May Require Information From Several Systems

Multifamily projects can involve:

  • Dwelling units
  • Common areas
  • Central systems
  • Individual HVAC systems
  • Central water heating
  • Individual water heating
  • Common-area lighting
  • Multiple envelope conditions

Because multifamily buildings can combine several systems, providing coordinated plans can reduce questions during the analysis.

What Information Is Needed for a New Home?

A new-home project can require a relatively complete description of the proposed building.

Useful information can include:

  • Floor plans
  • Elevations
  • Sections
  • Roof plans
  • Window schedules
  • Insulation assemblies
  • HVAC information
  • Duct locations
  • Ventilation
  • Water heating

The final calculations should correspond to the construction documents being submitted.

What Information Is Needed for an ADU?

ADUs can be:

  • New detached structures
  • Attached additions
  • Garage conversions
  • Conversions of other existing spaces

For an ADU, it is especially useful to show:

  • Existing construction
  • Proposed construction
  • New conditioned space
  • Walls
  • Roofs
  • Windows
  • Insulation
  • HVAC
  • Water heating

For more information, review ADU Title 24.

What Information Is Needed for an Addition?

Additions should clearly identify the relationship between the existing building and the new work.

Helpful information can include:

  • Existing floor plan
  • Proposed floor plan
  • New conditioned floor area
  • New exterior walls
  • New roof areas
  • New windows
  • New insulation
  • HVAC changes
  • Duct extensions

The plans should make it easy to understand which components already exist and which components are being added.

What Information Is Needed for Title 24 Calculations residential ADU addition and commercial projects

What Information Is Needed for a Garage Conversion?

Garage conversions often require careful documentation because space that was previously unconditioned is becoming conditioned living space.

Useful information can include:

  • Existing garage floor plan
  • Proposed floor plan
  • Existing walls
  • Proposed wall insulation
  • Ceiling or roof construction
  • Floor conditions
  • New windows
  • HVAC
  • Ventilation

Clearly distinguishing existing and proposed work can make the analysis more efficient.

What Information Is Needed for a Remodel?

The answer depends on what is actually changing.

A remodel can involve:

  • Windows
  • Exterior doors
  • Insulation
  • Roofing
  • HVAC equipment
  • Ducts
  • Water heating
  • Commercial lighting

AES needs information about the regulated components included in the project.

Purely cosmetic interior changes do not create the same energy-analysis needs as a remodel affecting the building envelope or mechanical systems.

What if I Already Have an Older Title 24 Report?

Send it.

An existing report can provide useful background about:

  • Previous project scope
  • Previous building geometry
  • Previous window assumptions
  • Previous insulation
  • Previous HVAC equipment
  • Previous compliance measures

However, AES should also receive the latest plans.

The older report may no longer match the current design.

What if the Building Department Already Issued Corrections?

Send the complete correction notice rather than only one selected comment.

AES should also receive:

  • The latest architectural plans
  • The previously submitted energy report
  • Revised mechanical plans when applicable
  • Revised electrical or lighting plans when applicable
  • Updated product specifications
  • A summary of significant project changes

The complete correction notice provides context and makes it easier to determine whether the issue requires:

  • A clarification
  • Updated forms
  • Revised calculations
  • New specifications
  • Plan coordination

Why Current Plans Matter More Than Old Plans

A Title 24 calculation is only useful when it represents the current project.

Submitting an old set of drawings can cause the analysis to use outdated:

  • Floor area
  • Window dimensions
  • Insulation
  • Roof construction
  • HVAC systems
  • Water heating
  • Lighting

If revised plans exist, send those rather than relying on the original design.

What Information Commonly Holds Up Final Calculations?

Some of the most common missing or conflicting items include:

  • Incomplete window schedules
  • Missing window-performance values
  • Unclear insulation assemblies
  • Missing roof details
  • Undecided HVAC equipment
  • Unknown duct locations
  • Incomplete water-heating information
  • Incomplete commercial lighting schedules
  • Conflicting floor areas
  • Plans from different revision dates

AES can identify these items during the initial review.

Do I Need Every Detail Before Contacting AES?

No.

You do not need to wait until every piece of information is perfect before asking for help.

A preliminary review can begin with the available plans.

AES can then identify:

  • What information is sufficient
  • What is missing
  • What needs clarification
  • Which products or systems still need to be selected

The final report still needs enough information to represent the proposed design accurately.

Can Preliminary Calculations Begin Before the Plans Are Final?

Potentially.

Early review can be useful because it gives the project team time to resolve energy-related design issues before permit submission.

However, final compliance documentation should not be prepared around temporary assumptions that no longer match the project.

As the design develops, provide updated plans when changes affect:

  • Floor area
  • Windows
  • Insulation
  • Roof assemblies
  • HVAC
  • Ducts
  • Water heating
  • Lighting

What Happens After AES Receives the Information?

The process generally follows several practical steps.

1. Review the Project Scope

AES determines whether the project involves new construction, an ADU, addition, garage conversion, remodel, multifamily project, commercial tenant improvement, HVAC work, lighting work, or another applicable scope.

2. Review the Plans and Specifications

The project documents are examined for the information needed to complete the applicable analysis.

3. Identify Missing or Conflicting Information

AES identifies details that still need clarification.

4. Complete the Applicable Energy Analysis

The proposed building features are evaluated using the appropriate compliance method.

5. Prepare the Compliance Documentation

The applicable forms are generated based on the project design and selected measures.

6. Coordinate the Report With the Plans

The energy documentation should correspond to the final construction drawings.

For additional technical information, review Title 24 energy calculations.

Why Better Information Can Reduce Revisions

The more accurately the plans represent the final project, the less likely the report will need to be changed simply because the original information was outdated or incomplete.

That does not mean a project will never change.

However, clear information can reduce revisions caused by:

  • Wrong floor area
  • Missing windows
  • Incorrect insulation assumptions
  • Wrong HVAC equipment
  • Outdated water-heating information
  • Incomplete commercial lighting data

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides professional Title 24 calculations, compliance documentation, report revisions, and energy-related plan-check support throughout California.

AES brings more than 30 years of California energy-compliance experience to:

  • New residential construction
  • ADUs
  • Garage conversions
  • Additions
  • Residential remodels
  • Multifamily projects
  • Mixed-use buildings
  • Commercial construction
  • Office tenant improvements
  • Retail projects
  • Restaurant improvements
  • Warehouse alterations
  • HVAC projects
  • Commercial lighting projects
  • Energy-related plan-check corrections

AES works from the actual project documents and identifies the information needed for the applicable analysis rather than relying on generic assumptions.

Learn more through the About Us page or review company background on the clients page.

What Information Is Needed for Title 24 Calculations contact Alternative Energy Systems

Send Your Plans or Call (626) 365-1518

If you are trying to determine What Information Is Needed for Title 24 Calculations, start by sending the most current plans you have.

A useful project package may include:

  • Floor plans
  • Exterior elevations
  • Building sections
  • Roof plans
  • Window and door schedules
  • Window specifications
  • Insulation details
  • HVAC specifications
  • Duct information
  • Ventilation information
  • Water-heating information
  • Commercial lighting schedules and controls when applicable
  • Existing Title 24 reports
  • Building-department correction comments

Not every project requires every item at the beginning.

Alternative Energy Systems can review what is available and tell you what additional information is needed to complete the calculations accurately.

Call (626) 365-1518, email info@title24energy.com, or use the contact page to begin.

When service and payment have already been arranged, payment can be completed through the AES payment page.

Frequently Asked Questions: What Information Is Needed for Title 24 Calculations?

What Information Is Needed for Title 24 Calculations?

Useful information can include floor plans, elevations, sections, roof plans, window schedules, insulation details, HVAC specifications, duct locations, ventilation, water heating, commercial lighting information when applicable, and existing correction comments.

Do I need a complete set of plans before contacting AES?

No. AES can review the available documents and identify what additional information is needed.

Are floor plans required?

Floor plans are usually one of the most useful documents because they help establish building geometry, conditioned areas, room layout, windows, doors, and the project scope.

Why are elevations needed?

Elevations can help confirm window placement, building height, roof configuration, exterior doors, and other exterior features.

Why are building sections useful?

Sections can show wall, ceiling, roof, floor, attic, and insulation conditions that may not be clear from floor plans alone.

Do I need a roof plan?

A roof plan can be useful when the project has several roof conditions, complicated geometry, or specific roof assemblies that affect the analysis.

Do I need a window schedule?

Window schedules are very helpful because the analysis can depend on window size, quantity, location, U-factor, solar heat gain coefficient, and glazed-door information.

Do I need the final window manufacturer?

Not always at the first review stage, but enough window-performance information must eventually be available for accurate final calculations.

What insulation information is needed?

Applicable wall, roof, ceiling, attic, floor, and other thermal-envelope insulation information can be needed.

What HVAC information is needed?

Useful information can include equipment type, heating and cooling efficiency, heat-pump information, number of systems, duct location, and ventilation.

Do I need exact HVAC model numbers before starting?

Not necessarily for an initial review, but final calculations require enough information to accurately represent the proposed system.

Why is duct location important?

Duct location can affect energy performance and applicable field-verification requirements.

What ventilation information is needed?

The answer depends on the project, but whole-building ventilation, local exhaust, or commercial outdoor-air information can be relevant.

What water-heating information is needed?

Useful information can include equipment type, energy source, efficiency, heat-pump configuration, and whether the system is central or individual.

What information is needed for commercial lighting?

Commercial projects can require fixture types, quantities, wattage, lighting-power information, and lighting-control plans.

Do multifamily projects require additional information?

They can. Multifamily projects may include dwelling units, common areas, central systems, individual systems, water heating, lighting, and multiple envelope conditions.

What information is needed for an ADU?

Current plans should clearly identify whether the ADU is detached, attached, or a conversion and show the applicable walls, roof, windows, insulation, HVAC, ventilation, and water heating.

What information is needed for a garage conversion?

Existing and proposed plans, wall and ceiling conditions, insulation, windows, HVAC, ventilation, and floor conditions can be useful.

What information is needed for an addition?

It is helpful to clearly show existing versus proposed construction, new conditioned floor area, new walls, roof areas, windows, insulation, and mechanical changes.

What information is needed for a remodel?

AES needs information about the energy-regulated components being changed, such as windows, insulation, roofing, HVAC, ducts, water heating, or commercial lighting.

Should I send an old Title 24 report?

Yes. An old report can provide useful background, but it should be reviewed together with the current plans.

Should I send building-department correction comments?

Yes. Send the complete correction notice whenever possible rather than only one isolated comment.

What if my plans are incomplete?

Send what you have. AES can review the available material and identify which missing items are necessary before the final analysis can be completed.

Can calculations begin before plans are final?

Preliminary review can often begin earlier, but final compliance documentation requires enough project information to accurately represent the proposed design.

What commonly delays the calculations?

Missing window data, unclear insulation, incomplete roof details, undecided HVAC systems, unknown duct locations, incomplete water-heating information, conflicting floor areas, and incomplete commercial lighting information can all create delays.

Do the report and plans need to match?

Yes. The energy documentation should represent the same current project shown in the construction drawings.

What happens after I send the plans?

AES reviews the project scope, examines the available documents, identifies missing information, prepares the applicable analysis and forms, and coordinates the resulting energy measures with the plans.

What should I send first if I am unsure?

Start with the most current floor plans, elevations, sections, roof plans, window information, insulation details, and available mechanical specifications.

How do I get started?

Call Alternative Energy Systems at (626) 365-1518 or send the current project information through the contact page.

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