Which Title 24 Energy Code Version Do I Need?

Call (626) 365-1518 | Alternative Energy Systems

Which Title 24 Energy Code Version Do I Need is usually answered by looking first at the applicable building permit application date.

For most current California projects:

• Permit applications submitted on or after January 1, 2026: 2025 California Energy Code
• Permit applications submitted from January 1, 2023 through December 31, 2025: 2022 California Energy Code
• Permit applications submitted from January 1, 2020 through December 31, 2022: 2019 California Energy Code

For a new permit application today, the current statewide edition is the 2025 Building Energy Efficiency Standards, which became effective January 1, 2026.

The year printed on the code and the year it becomes effective are not the same thing.

That is why a document identified as the 2025 Energy Code is the current code during 2026.

The answer can become more complicated when a project has:

• An older permit application
• An expired permit
• An existing Title 24 report
• Plans originally prepared under another code cycle
• Major design revisions
• A building-department resubmittal
• A permit application that crosses from one code cycle into another

Alternative Energy Systems brings more than 30 years of California energy-compliance experience to residential, multifamily, mixed-use, and commercial projects.

Call (626) 365-1518 if you have an older report or uncertain permit history and need help determining which energy documentation should be prepared.

The Current Title 24 Energy Code Is the 2025 Edition

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

The Energy Code is primarily contained in:

California Code of Regulations, Title 24, Part 6.

For additional general background about the code itself, review the California Energy Code overview on Wikipedia.

The 2025 Energy Code applies to applicable:

• New single-family construction
• New multifamily construction
• New nonresidential construction
• Additions
• Alterations

The exact requirements depend on building type, project scope, climate zone, systems being changed, and the compliance method being used.

Quick Energy Code Version Guide

Permit Application Date	Applicable Energy Code Cycle
January 1, 2026 and later	2025 Energy Code
January 1, 2023 through December 31, 2025	2022 Energy Code
January 1, 2020 through December 31, 2022	2019 Energy Code

Projects with older permit histories can involve earlier code editions.

Do not choose the code cycle simply from the date printed on the architectural drawings.

The permit history is usually more important.

Start With Three Questions

When trying to identify the correct Energy Code edition, begin with:

1. When was the applicable permit application submitted?
2. Is that permit application still active?
3. Is the current work still part of that same permit scope?

For a completely new permit application, the answer is generally straightforward.

For a project that began several years ago, those questions become much more important.

Why Is the 2025 Energy Code Effective in 2026?

California’s code editions are named for the code cycle rather than the first calendar year in which they are enforced.

For example:

• The 2019 Energy Code became effective January 1, 2020
• The 2022 Energy Code became effective January 1, 2023
• The 2025 Energy Code became effective January 1, 2026

Therefore, seeing “2025” on a current Title 24 report prepared during 2026 does not mean the report is using an outdated code.

It identifies the current edition.

The Permit Application Date Usually Determines the Code Cycle

One of the most common mistakes is using the wrong project date.

The following dates do not necessarily establish the Energy Code edition:

• The date the property was purchased
• The date the architect began drawing
• The date the contractor prepared an estimate
• The date the owner approved the project
• The date preliminary calculations were started
• The date the first consultant was contacted

For ordinary new permit applications, the building permit application date is the key date used to determine the code cycle.

That means plans prepared near the end of one code cycle can require updating when the permit application is not submitted until the next cycle begins.

If I Submit a New Permit Application Now, Which Version Do I Need?

A new applicable permit application submitted now should use the 2025 Energy Code.

That means the project should use the appropriate current:

• Energy Code requirements
• Compliance forms
• Prescriptive requirements
• Performance requirements
• Calculation procedures
• Approved compliance software when performance modeling is used

Using forms from a previous project without checking their code cycle can lead to unnecessary corrections.

What if My Plans Were Drawn Under the 2022 Energy Code?

Plans can remain architecturally useful even when the applicable Energy Code changes.

However, the energy documentation may need to be updated.

If a project was designed during the 2022 code cycle but the permit application is submitted on or after January 1, 2026, the energy-related design should be reviewed under the 2025 Energy Code.

Potential updates can involve:

• Calculations
• Compliance software
• Compliance forms
• Window specifications
• Mechanical assumptions
• Water-heating requirements
• Ventilation requirements
• Other applicable measures

What if My Report Was Finished Before the New Code Took Effect?

The completion date of the report by itself does not lock in the previous Energy Code cycle.

Suppose a report was completed under the 2022 Energy Code in December 2025, but no applicable permit application was filed until February 2026.

The permit application is now occurring after the 2025 Energy Code effective date.

The old report should therefore be reviewed before submission.

Simply changing the date printed on the report does not convert it to the newer Energy Code.

An Old Report Cannot Be Updated by Changing the Cover Page

A new code cycle can change:

• Calculation methodology
• Standard-design assumptions
• Prescriptive requirements
• Mandatory measures
• Compliance forms
• Compliance software
• Verification requirements

That means the underlying analysis may need to be recalculated.

Changing only:

• The date
• The code year
• The cover sheet

does not establish compliance with the newer code.

What if My Permit Application Was Submitted Before January 1, 2026?

An applicable permit application submitted before January 1, 2026 may have been established under the 2022 Energy Code.

The 2022 code cycle applied to permit applications submitted from January 1, 2023 through December 31, 2025.

However, older applications need closer review when:

• The application was abandoned
• The application became inactive
• The permit expired
• The building department requires a new application
• The project was substantially redesigned
• The scope of work changed

When any of those conditions exists, confirm the permit status with the authority having jurisdiction before assuming that the older Energy Code still applies.

Does an Active Older Permit Automatically Change to the 2025 Energy Code?

Not simply because the calendar changed.

A project established under a valid earlier permit process can have different circumstances from a completely new application submitted after January 1, 2026.

Questions to answer include:

• When was the original application submitted?
• Was the application accepted?
• Was the permit issued?
• Is the permit still active?
• Has the permit expired?
• Has the construction scope materially changed?
• Is a new permit application required?

The building department should confirm how it is treating the permit.

AES can then prepare energy documentation corresponding to that determination.

What if My Permit Expired?

An expired permit can create a different code-cycle issue from an active permit.

Depending on the building department, the project may require:

• Permit renewal
• Permit reactivation
• A new permit application
• Updated construction plans
• Updated code compliance

If the jurisdiction requires a completely new permit application during the current code cycle, the project may need to comply with the 2025 Energy Code.

Do not automatically reuse the original calculations until the permit status has been confirmed.

What if the Building Department Requires a New Permit Application?

This can be an important dividing line.

If an old application has been closed and a new permit application is required, the new application’s date can determine the applicable Energy Code cycle.

That can mean an older project needs:

• New calculations
• Current forms
• Updated compliance software
• Updated specifications
• Plan revisions

The amount of work depends on how much the code and project design have changed.

What if I Am Only Resubmitting Plan-Check Corrections?

A plan-check resubmittal is not necessarily the same as starting a new permit application.

The important question is whether the original permit application remains active.

If it does, the original code cycle may still control.

If the jurisdiction considers the project a new application, current requirements may apply.

When in doubt, ask the building department which Energy Code cycle it expects on the resubmittal.

What if I Am Revising an Issued Permit?

A revision to an active issued permit can also require project-specific review.

The applicable code treatment can depend on:

• The original permit
• The original code cycle
• The extent of the revision
• The jurisdiction’s procedures

Do not assume that every post-permit revision automatically changes the entire project to the newest code.

Likewise, do not assume a major redesign can always remain under the original analysis.

Confirm the permit status first.

Why Can’t I Choose the Older Code?

For a new permit application, the applicable Energy Code is not normally a matter of personal preference.

You generally cannot choose the previous edition simply because:

• The plans were already drawn
• The old calculations are finished
• The previous requirements appear easier
• The contractor is familiar with the old forms

The permit circumstances determine the applicable code.

An older code remains relevant when the project has a valid earlier permit status recognized by the enforcement authority.

Why Can’t I Automatically Choose the Newer Code for an Older Permit?

Changing code cycles can also create problems.

An existing project may already have:

• Approved drawings
• Energy calculations
• Mechanical selections
• Compliance forms
• Plan-check approvals

prepared under a particular edition.

Moving voluntarily into another code cycle can affect all of those documents.

Coordinate with the building department before changing the Energy Code basis of an existing permit.

Why Do Energy Code Versions Matter?

California updates the Building Energy Efficiency Standards every three years.

The changes are not merely editorial.

Different code cycles can change requirements involving:

• Building envelope
• Insulation
• Windows
• Roof assemblies
• HVAC systems
• Heat pumps
• Ventilation
• Water heating
• Lighting
• Lighting controls
• Solar systems
• Battery storage
• Electric readiness

A design that passed under an earlier edition should therefore not automatically be assumed to pass under the current edition.

The 2025 Energy Code Is Not the 2022 Code With a Different Date

The 2025 edition includes substantive changes affecting residential, multifamily, and nonresidential buildings.

Updated areas include provisions involving:

• Heat-pump technology
• Space heating
• Water heating
• Electric-ready construction
• Ventilation
• Building envelope performance
• Solar photovoltaic systems
• Battery-energy storage
• Nonresidential mechanical systems

The correct code edition should therefore be established before final energy calculations are prepared.

Does the Compliance Software Change With the Code Cycle?

Yes.

Performance compliance software is approved for specific Energy Code editions.

The California Energy Commission approves software for the current code and specific building categories.

The approved software can vary according to:

• Single-family buildings
• Multifamily buildings
• Nonresidential buildings
• New construction
• Additions
• Alterations

Permit applications submitted on or after January 1, 2026 that use the performance method must use approved 2025 Energy Code compliance software.

For official information, review the California Energy Commission 2025 Energy Code Compliance Software information.

Can I Use 2022 Software for a New 2026 Permit Application?

Not when the project must demonstrate performance compliance under the current 2025 Energy Code.

Older software was designed around the requirements and calculation procedures of its own code cycle.

A previous model can sometimes provide useful background information, but the current compliance analysis needs to use an approved method for the applicable code.

Do the Compliance Forms Change Too?

Yes.

Compliance forms correspond to particular Energy Code editions.

Forms can also differ according to:

• Building category
• Project scope
• New construction
• Additions
• Alterations
• Mechanical systems
• Lighting systems
• Installation requirements
• Verification requirements

An old form should not be reused solely because a project appears similar to a previous job.

Which Version Do I Need for a New Home?

For a new applicable residential permit application submitted on or after January 1, 2026, the current 2025 Energy Code applies.

Energy compliance can involve:

• Building size
• Climate zone
• Orientation
• Walls
• Roof assemblies
• Windows
• Insulation
• HVAC
• Ducts
• Ventilation
• Water heating

The applicable forms and calculations should match the current code cycle.

Which Version Do I Need for an ADU?

A new ADU permit application submitted on or after January 1, 2026 generally uses the 2025 Energy Code.

This can include:

• Detached ADUs
• Attached ADUs
• Garage conversions
• Conversions of other existing spaces

Existing conditions can affect which requirements apply, but the applicable code cycle still needs to be established first.

For more information, review ADU Title 24.

Which Version Do I Need for an Addition?

A new applicable addition permit application submitted under the current code cycle uses the 2025 Energy Code.

The project may then demonstrate compliance through:

• An applicable prescriptive approach
• A performance approach
• Other project-specific compliance documents

depending on the addition.

For more information about the calculations themselves, review Title 24 energy calculations.

Which Version Do I Need for a Remodel?

A remodel can trigger current Energy Code requirements when it alters regulated components.

Examples include:

• Windows
• Insulation
• Exterior walls
• Roofing
• HVAC
• Ducts
• Water heating
• Commercial lighting

The code cycle is determined by the applicable permit circumstances.

The amount of compliance documentation depends on the actual alteration scope.

Which Version Do I Need for HVAC Work?

Mechanical alterations can require current code-cycle-specific forms and requirements.

Depending on the project, that can affect:

• Equipment efficiency
• Equipment type
• Duct systems
• Controls
• Airflow
• Verification measures

Using an old mechanical compliance form for a current permit application can create unnecessary corrections.

Which Version Do I Need for a Multifamily Project?

Multifamily buildings have dedicated Energy Code requirements and compliance documentation.

A current multifamily permit application can involve:

• New dwelling units
• Common areas
• Building-envelope requirements
• Mechanical systems
• Water heating
• Lighting
• Other applicable systems

The project should be classified correctly before the applicable forms or calculations are selected.

Which Version Do I Need for a Commercial Project?

New nonresidential permit applications submitted on or after January 1, 2026 use the current 2025 Energy Code for applicable work.

Commercial energy compliance can involve:

• Building envelope
• Storefront glazing
• Mechanical systems
• Ventilation
• Service water heating
• Interior lighting
• Exterior lighting
• Lighting controls

For professional assistance, review Title 24 compliance services.

Which Version Do I Need for a Commercial Tenant Improvement?

A tenant improvement can be governed by the current Energy Code even when the original building was constructed decades ago.

A current alteration may affect:

• Lighting
• Lighting controls
• HVAC equipment
• Ventilation
• Water heating
• Storefront glazing

The age of the original building does not automatically determine the code applied to new alteration work.

Does the 2025 Energy Code Apply to Existing Buildings?

It can apply to applicable new work performed in existing buildings.

California’s Energy Code regulates applicable:

• Additions
• Alterations

This does not mean every existing building must be completely upgraded whenever a new code cycle becomes effective.

The requirements attach according to the regulated construction being performed.

For example, an older building can have current Energy Code requirements for:

• A new addition
• A window alteration
• An HVAC replacement
• A tenant improvement
• A lighting alteration

without requiring the entire original building to be rebuilt.

Does the Building’s Original Construction Date Determine the Version?

No.

The building may have been constructed under an older code while new work is reviewed under a current code.

A building completed in the 1980s can still have a 2025 Energy Code requirement when a new permit application involves regulated alterations during the current cycle.

The project scope and permit timing matter more than the age of the original structure.

Does the Code Version Determine Whether I Need Performance Calculations?

Not by itself.

The code version establishes which rules apply.

The project and selected compliance method determine whether compliance is demonstrated through:

• Prescriptive requirements
• Performance calculations
• System-specific compliance documents

Two projects under the same 2025 Energy Code can use different compliance approaches.

Can I Use My Old Report as a Starting Point?

Yes, an older report can be useful background information.

It can help identify:

• Previous building geometry
• Previous window assumptions
• Previous insulation
• Previous mechanical systems
• Previous compliance measures

However, AES should also receive the current plans.

The old report should not be assumed to represent the current project or current code cycle without review.

What if My Old Report and Current Plans Do Not Match?

The current design should be identified before the energy documentation is finalized.

Differences can involve:

• Floor area
• Room configuration
• Windows
• Insulation
• Roof assemblies
• HVAC
• Water heating
• Lighting

A report prepared correctly for an old design can still be incorrect for the current project.

What if the Architectural Plans and Report Show Different Code Years?

Resolve the conflict before submission.

The permit package should not contain one sheet referencing the 2022 Energy Code while the calculations and forms reference the 2025 Energy Code without a valid reason.

A mismatch may indicate:

• Old plan notes
• An outdated report
• Old forms
• A project carried forward from an earlier permit cycle
• An unresolved code-transition issue

Do not simply edit the code year on one document without checking the underlying project requirements.

What if the Building Department Says I Used the Wrong Version?

Send AES:

• The complete correction notice
• The current plan set
• The existing Title 24 report
• Available permit information
• Current mechanical information
• Current window specifications
• Other updated project specifications

AES can review the energy documentation and determine whether new calculations, forms, or plan coordination are required.

What if I See Information About the 2028 Energy Code?

Future standards can be developed and discussed before they become effective.

That does not make the future code the current enforceable edition for ordinary permit applications.

The current statewide Energy Code for applicable new permit applications is the 2025 edition.

When evaluating an online code reference, check:

• The edition
• The effective date
• Whether it is current or proposed

rather than assuming the highest year number is the version your project should use.

Why the Code Keeps Changing

California updates its Building Energy Efficiency Standards through a three-year cycle.

Updates can reflect changes in:

• Construction practices
• Building technology
• HVAC technology
• Water-heating technology
• Energy efficiency
• Grid conditions
• Building performance

That regular cycle is why existing energy documentation should be checked whenever a project remains inactive for several years.

What Should I Send AES if I Am Unsure Which Version Applies?

For a straightforward new project, the permit date can make the answer simple.

For an older project, send as much permit history as is reasonably available.

Helpful information can include:

• Current floor plans
• Previous floor plans
• Existing Title 24 reports
• Existing compliance forms
• Permit application information
• Permit number
• Permit issuance information
• Plan-check comments
• Correction notices
• Current mechanical plans
• Current project specifications

AES can review the energy-documentation side of the project.

When the answer depends on whether an older permit remains legally active, the applicable building department should confirm that permit status.

Before sending documents, review what AES will need from you.

What Happens After the Correct Version Is Identified?

Once the applicable code cycle is known, AES can move forward with the appropriate compliance process.

1. Review the Current Project Scope

The actual proposed work is identified.

2. Confirm the Building Category

The project is classified as applicable single-family, multifamily, nonresidential, or another relevant category.

3. Determine the Compliance Path

AES evaluates whether the project uses applicable prescriptive, performance, or system-specific documentation.

4. Use the Appropriate Code-Cycle Documents

The calculations, forms, and software should correspond to the applicable Energy Code edition.

5. Coordinate the Results With the Plans

Energy-related measures should agree with the current construction drawings.

6. Revise the Documentation if the Design Changes

Significant changes can require the energy analysis or forms to be updated.

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 buildings
• Commercial construction
• Office tenant improvements
• Retail projects
• Restaurant projects
• Warehouse alterations
• HVAC projects
• Commercial lighting projects
• Older reports that need review
• Energy-related plan-check corrections

AES evaluates the actual plans and available permit information rather than assuming that an older report, plan note, or previous project automatically uses the correct Energy Code edition.

Learn more through the About Us page or review company background on the clients page.

Find Out Which Title 24 Energy Code Version Your Project Needs

Call (626) 365-1518 | Alternative Energy Systems

The simplest answer to Which Title 24 Energy Code Version Do I Need starts with the applicable permit application date.

For most projects:

• January 1, 2026 and later: 2025 Energy Code
• January 1, 2023 through December 31, 2025: 2022 Energy Code
• January 1, 2020 through December 31, 2022: 2019 Energy Code

Older active permits, expired permits, major revisions, and projects being resubmitted can require additional review.

Alternative Energy Systems can review your current plans and existing energy documentation and prepare the appropriate compliance package once the applicable code cycle has been established.

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: Which Title 24 Energy Code Version Do I Need?

Which Title 24 Energy Code Version Do I Need?

For most projects, the applicable code version is determined by the permit application date. Applicable new permit applications submitted on or after January 1, 2026 use the 2025 Energy Code.

What Title 24 Energy Code is currently in effect?

The current statewide Energy Code is the 2025 California Building Energy Efficiency Standards.

When did the 2025 Energy Code become effective?

January 1, 2026.

Why is it called the 2025 Energy Code if it became effective in 2026?

2025 identifies the code edition. January 1, 2026 is the effective date.

Which code was in effect before the 2025 edition?

The previous statewide edition was the 2022 Energy Code.

When did the 2022 Energy Code apply?

It applied to applicable permit applications submitted beginning January 1, 2023 and remained the current cycle through December 31, 2025.

What came before the 2022 Energy Code?

The 2019 Energy Code became effective January 1, 2020.

Does the date my plans were drawn determine the Energy Code?

Not generally. For ordinary new permit applications, the permit application date is usually the key code-cycle date.

What if my plans were drawn in 2025 but submitted in 2026?

A new applicable permit application submitted on or after January 1, 2026 generally needs to comply with the 2025 Energy Code.

What if my report was prepared under the 2022 Energy Code but never submitted?

If the permit application is now being submitted under the 2025 code cycle, the older report should be reviewed and may require new calculations and forms.

Can I change the date on an old Title 24 report?

Changing the date does not update the underlying Energy Code calculations, software, forms, or compliance assumptions.

Does an old active permit automatically change to the newest code?

Not simply because the calendar changes. The building department should confirm the status of an older active permit.

What if my permit expired?

The jurisdiction may require renewal, reactivation, or a new permit application. A new application can potentially trigger the current code cycle.

What if I am only responding to corrections?

If the original permit application remains active, the existing code cycle may still apply. Confirm unusual situations with the building department.

What if I am revising an already issued permit?

The applicable treatment depends on the original permit, code cycle, scope of the revision, and jurisdiction procedures.

Can I choose the older Energy Code?

A new permit application generally cannot choose an older code solely because the previous requirements are preferred.

Can I voluntarily switch an older project to the newest Energy Code?

Do not change code cycles without first coordinating with the enforcement authority because the change can affect plans, calculations, forms, and specifications.

Do compliance forms change between code cycles?

Yes. Compliance forms correspond to specific Energy Code editions and project types.

Does compliance software change between code cycles?

Yes. Performance software is approved for specific Energy Code editions, occupancies, and project scopes.

Can I use 2022 software for a new 2026 permit application?

Not when the project must demonstrate performance compliance under the 2025 Energy Code.

Which code does a new home use now?

A new applicable permit application submitted on or after January 1, 2026 uses the 2025 Energy Code.

Which code does a new ADU use now?

A new applicable ADU permit application submitted during the current cycle generally uses the 2025 Energy Code.

Which code does an addition use?

The edition associated with the applicable permit application generally controls the addition’s Energy Code requirements.

Which code does a remodel use?

Applicable alterations use the code cycle associated with the permit circumstances and actual regulated scope.

Which code does an HVAC replacement use?

Applicable current mechanical alterations should use the requirements and forms associated with the applicable permit’s Energy Code cycle.

Which code does a commercial tenant improvement use?

A new applicable tenant-improvement permit application submitted on or after January 1, 2026 uses the current 2025 Energy Code for regulated work.

Does the age of the building determine the Energy Code edition?

No. An older building can have new work regulated under the current Energy Code.

Does an existing building have to be completely upgraded to the current code?

Not automatically. Current requirements apply according to the applicable addition or alteration scope.

Does the code edition determine whether I use performance or prescriptive compliance?

No. The edition establishes the requirements. The building type, scope, and selected compliance path determine the appropriate method.

What if my architect and Title 24 report list different code years?

Resolve the discrepancy before submission. The permit documents and energy documentation should correspond to the same applicable code cycle.

What if the building department says I used the wrong code?

Send AES the complete correction notice, current plans, existing report, and available permit information for review.

Is the 2028 Energy Code currently required?

No. Future standards can be under development before they become effective. The current statewide edition for applicable new permit applications is the 2025 Energy Code.

What should I send AES if I am unsure which code applies?

Send the current plans, previous Title 24 documentation, available permit information, and any building-department comments.

How do I get started?

Call Alternative Energy Systems at (626) 365-1518 and provide the current project plans and available permit information for review.

How Much Do Title 24 Calculations Cost?

Call (626) 365-1518 | Alternative Energy Systems

How Much Do Title 24 Calculations Cost depends on the actual building project rather than one universal price that applies to every home, ADU, addition, remodel, multifamily building, or commercial project.

The cost can depend on:

• Project type
• Building size
• Project complexity
• New construction versus alteration
• Residential, multifamily, or commercial classification
• Amount of conditioned space
• Complexity of the building envelope
• Number and type of windows
• Mechanical-system complexity
• Whether commercial lighting is involved
• How complete the plans are
• Whether important specifications are missing
• Whether an existing report must be revised
• Whether building-department correction comments already exist
• Turnaround requirements
• Extent of requested revisions

A straightforward project with coordinated plans and complete specifications can involve a different amount of work from a custom residence, multifamily project, mixed-use building, restaurant improvement, or commercial project involving several design disciplines.

Alternative Energy Systems therefore reviews the project before providing pricing.

Call (626) 365-1518 or send the current plans through the contact page to request a project-specific quote.

There Is No Single Price That Accurately Fits Every Project

Two projects with similar square footage can require very different amounts of energy-compliance work.

One project may have:

• Simple building geometry
• One wall assembly
• A straightforward roof
• A complete window schedule
• One HVAC system
• Complete specifications

Another building of similar size may include:

• Several roof elevations
• Multiple wall assemblies
• Extensive glazing
• Several HVAC systems
• Mixed conditioned and unconditioned spaces
• Existing and proposed construction
• Incomplete product information

The amount of work required to review, analyze, coordinate, and document those projects is not the same.

That is why project-specific pricing is more useful than a generic number.

Project Type Is One of the Biggest Pricing Factors

The first question is usually what kind of project is being analyzed.

AES works with projects including:

• New homes
• ADUs
• Garage conversions
• Residential additions
• Residential remodels
• Multifamily buildings
• Mixed-use projects
• Commercial buildings
• Office tenant improvements
• Retail improvements
• Restaurant projects
• Warehouse alterations
• HVAC projects
• Commercial lighting projects

Each project category can involve different calculations, forms, systems, and coordination requirements.

Building Size Can Affect the Cost

Larger projects can require more information to be reviewed and entered into the energy analysis.

Depending on the project, that may include additional:

• Floor area
• Exterior wall area
• Roof assemblies
• Windows
• Mechanical systems
• Zones
• Lighting areas

However, square footage should not be treated as the only pricing factor.

A smaller building with complicated geometry, several system types, or incomplete plans can require more coordination than a larger but straightforward project.

Complex Building Geometry Can Increase the Work Required

Energy analysis becomes more involved when the building contains many different conditions.

Examples include:

• Multiple stories
• Several roof elevations
• Vaulted ceilings
• Complex exterior-wall geometry
• Numerous projections or recesses
• Large amounts of glazing
• Multiple conditioned zones
• Attached and detached portions

These characteristics can require additional review and modeling.

Complete Plans Can Help Control the Cost

A well-developed plan set can reduce the time spent identifying basic project information.

Helpful documents include:

• Floor plans
• Exterior elevations
• Building sections
• Roof plans
• Window schedules
• Insulation notes
• Mechanical information
• Water-heating information
• Commercial lighting plans when applicable

Incomplete plans do not necessarily prevent AES from reviewing a project.

However, missing information can require additional communication, revised assumptions, or later updates.

Before requesting pricing, review what AES will need from you.

Missing Specifications Can Affect Pricing and Timing

A project can appear complete architecturally while still lacking information required for the energy analysis.

Common missing items can include:

• Window U-factor
• Solar heat gain coefficient
• Wall insulation
• Roof insulation
• HVAC efficiency
• Duct location
• Water-heating specifications
• Commercial fixture wattage
• Lighting-control information

If these details have to be resolved during the calculation process, the project can involve more coordination than one submitted with complete specifications.

New Construction Pricing Can Differ From Addition or Alteration Pricing

A newly constructed building can require analysis of the complete energy-related design.

That can include:

• Building geometry
• Climate zone
• Orientation
• Walls
• Roof assemblies
• Floors
• Windows
• Insulation
• HVAC
• Duct systems
• Ventilation
• Water heating

An alteration may involve a much narrower set of systems.

An addition can fall somewhere between those two depending on its size and compliance path.

The price should therefore reflect the actual scope rather than only the property type.

How Much Do Calculations Cost for an ADU?

ADU pricing depends partly on how the ADU is being created.

A project may involve:

• A newly constructed detached ADU
• An attached ADU
• A garage conversion
• A conversion of another existing structure

A new detached ADU may require analysis of a complete building envelope and mechanical design.

A garage conversion may instead require careful review of existing and proposed construction.

Relevant pricing factors can include:

• ADU size
• Building configuration
• Window design
• Existing conditions
• Mechanical system
• Completeness of the plans

For project-specific information, review ADU Title 24 or call AES for a quote.

How Much Do Calculations Cost for a Residential Addition?

Addition pricing varies because additions range from relatively simple room expansions to major second-story projects.

Factors can include:

• Amount of new conditioned floor area
• New exterior walls
• Roof complexity
• Number of windows
• HVAC changes
• Duct extensions
• Interaction with the existing building
• Compliance method

Some additions can use applicable prescriptive compliance documentation.

Others may involve performance calculations.

The selected compliance path can change the amount of work required.

How Much Do Calculations Cost for a Garage Conversion?

Garage conversions can involve different work than either a completely new building or a simple remodel.

AES may need to evaluate:

• Existing wall construction
• New insulation
• Floor conditions
• Roof or ceiling conditions
• New windows
• HVAC
• Ventilation

Clearly distinguishing existing and proposed construction can make the review more efficient.

How Much Do Calculations Cost for a Residential Remodel?

Residential remodel pricing depends on how much energy-regulated work is actually being changed.

A project involving only limited alterations can be different from a whole-house remodel that changes:

• Windows
• Exterior walls
• Insulation
• Roof assemblies
• HVAC systems
• Ductwork
• Water heating

The word “remodel” alone is not enough to determine the price.

AES needs to understand the actual construction scope.

How Much Do Calculations Cost for a New Home?

New-home calculations can depend on:

• Total conditioned floor area
• Number of stories
• Building geometry
• Window quantity and orientation
• Envelope complexity
• Roof design
• Number of HVAC systems
• Water-heating design
• Selected compliance path

A custom house with complex geometry and extensive glazing can require a different amount of work from a straightforward residential design.

How Much Do Calculations Cost for Multifamily Projects?

Multifamily pricing can vary significantly depending on the building configuration.

The project may include:

• Multiple dwelling units
• Common spaces
• Central mechanical systems
• Individual mechanical systems
• Central water heating
• Common-area lighting
• Multiple envelope conditions

Larger multifamily projects can also require coordination among several design professionals.

The quote should therefore be based on the specific plans and systems rather than simply the number of units.

How Much Do Commercial Calculations Cost?

Commercial projects can vary even more widely because the energy documentation may involve several disciplines.

Depending on the project, AES may need to review:

• Architectural plans
• Mechanical plans
• Electrical plans
• Lighting schedules
• Lighting controls
• Ventilation
• Service water heating
• Envelope information

A small office tenant improvement is not the same scope as a restaurant, warehouse, mixed-use project, or newly constructed commercial building.

For broader information, review Title 24 compliance services.

Commercial Lighting Can Affect the Price

A commercial project may require lighting compliance work involving:

• Fixture types
• Fixture quantities
• Fixture wattage
• Space classifications
• Lighting power
• Occupancy controls
• Automatic shutoff controls
• Daylighting controls
• Exterior lighting

A project with complete lighting schedules can be easier to evaluate than one where fixtures or controls are still being designed.

Mechanical Complexity Can Affect the Price

Projects with several HVAC systems can require additional analysis and coordination.

Mechanical factors can include:

• System type
• Equipment efficiency
• Heat pumps
• Number of systems
• Duct configuration
• Ventilation
• Controls

Changing equipment during the analysis can also require additional review.

Performance Modeling and Prescriptive Compliance Can Have Different Scopes

California energy compliance can use different methods.

Prescriptive Compliance

A qualifying project can follow applicable component and system requirements.

This may use project-specific forms without requiring a complete whole-building performance model.

Performance Compliance

Performance analysis uses approved software to evaluate the proposed design against the applicable standard design or energy budget.

This can involve detailed modeling of:

• Building geometry
• Orientation
• Envelope assemblies
• Windows
• Mechanical systems
• Other applicable energy features

The amount of work associated with each method can differ.

The correct compliance path should be determined from the actual project rather than selected only on price.

Can Design Tradeoffs Affect the Cost of the Analysis?

They can.

A project using performance compliance may need additional evaluation when the design initially does not meet the applicable performance target.

The project team may consider changes involving:

• Windows
• Glazing area
• Insulation
• Roof characteristics
• HVAC efficiency
• Other qualifying measures

Additional modeling or redesign coordination can increase the amount of work associated with the project.

Does Climate Zone Affect Pricing?

Climate zone is an important technical input in California energy compliance, but it is generally only one part of the overall project scope.

A project’s price is more likely to be influenced by the complete combination of:

• Building type
• Size
• Complexity
• Envelope
• Systems
• Documentation
• Revisions

Climate zone can influence the calculations themselves, while project complexity influences the amount of consulting work required.

Do Revisions Cost Extra?

Revision pricing depends on the agreed scope and the extent of the change.

Do not assume that every possible future design revision is automatically included in the original calculation fee.

A minor update can be very different from:

• Changing conditioned floor area
• Adding or removing rooms
• Changing multiple windows
• Changing the roof design
• Changing the HVAC system
• Revising commercial lighting
• Responding to significant plan-check changes

The project-specific quote or agreement should define the applicable scope.

Do Building Department Corrections Affect the Cost?

They can, depending on what the building department requests and the scope of the original service.

A correction might involve a simple clarification.

Another comment may require:

• Revised calculations
• Updated forms
• Changed project specifications
• New mechanical information
• Updated lighting information
• Coordination with revised plans

Send AES the complete correction notice so the required work can be evaluated accurately.

Does the Initial Fee Include Unlimited Plan Changes?

Do not assume so.

A Title 24 calculation is based on a specific project design.

If that design changes substantially, additional work may be necessary.

The quote should be reviewed for the scope of included services and revisions.

Changes initiated after the original analysis can involve additional work when they affect the energy model or compliance forms.

Can Incomplete Plans Make the Project More Expensive?

Potentially.

Incomplete plans can lead to:

• Additional review
• More follow-up questions
• Temporary assumptions
• Later recalculation
• Repeated plan coordination

Sending the most developed current plans available can reduce avoidable duplication of work.

Can Changing Windows Increase the Cost?

Potentially, if the change requires the calculations or forms to be revised.

Window changes can involve:

• Quantity
• Size
• Orientation
• U-factor
• Solar heat gain coefficient

A substantial change made after the original analysis may require additional modeling.

Can Changing HVAC Equipment Increase the Cost?

Potentially.

The existing report should be reviewed when the project changes:

• Equipment type
• Heating efficiency
• Cooling efficiency
• Heat-pump configuration
• Duct conditions

A simple product substitution may require less work than redesigning the entire mechanical system.

Does Faster Turnaround Affect Pricing?

Turnaround requirements can be a pricing factor.

A project requiring accelerated handling can involve different scheduling demands from one with a normal project timeline.

Availability and project complexity still matter.

Call AES to discuss both the scope and requested schedule rather than assuming every project can be completed under the same expedited conditions.

Are Field Verification or HERS Services Included in the Calculation Price?

Some residential projects can trigger separate field verification or diagnostic testing.

The Title 24 calculations may identify those requirements, but the calculations themselves are not the field verification.

Do not assume third-party testing or verification is automatically included in the calculation fee.

The project-specific quote should be reviewed to determine what services are included and what must be coordinated separately.

Is Commercial Acceptance Testing Included?

Commercial acceptance testing is separate from preparation of the original energy analysis.

Applicable projects may require later testing of certain:

• Lighting controls
• Mechanical systems
• Other regulated systems

Do not assume these construction-stage services are included in the Title 24 calculation quote unless the scope specifically states that they are.

Does the Calculation Fee Include Building Department Permit Fees?

A consulting fee for preparing energy calculations should not automatically be treated as a building permit fee.

Building departments can charge their own permit, plan-check, or administrative fees.

Those governmental charges are separate from the professional work involved in preparing the energy-compliance documentation unless a specific agreement states otherwise.

Does Paying for the Calculations Guarantee Permit Approval?

No.

Title 24 calculations address the energy-compliance portion of the project.

The building department can separately review:

• Architecture
• Structure
• Electrical work
• Mechanical work
• Plumbing
• Fire and life safety
• CALGreen
• Other applicable requirements

Paying for professional energy calculations does not guarantee complete building-department approval.

What Should a Project-Specific Quote Be Based On?

To provide meaningful pricing, AES may need to understand:

• What is being built
• Whether the work is new construction or an alteration
• Approximate building size
• Building type
• Plan completeness
• Mechanical-system complexity
• Whether commercial lighting is involved
• Whether an existing report must be revised
• Whether building-department comments already exist
• Requested turnaround

Providing the current plans is usually much more useful than describing the project only by square footage.

What Should I Send to Get a Quote?

Send the most current project information available.

Useful documents can include:

• Floor plans
• Exterior elevations
• Building sections
• Roof plans
• Window schedules
• Insulation notes
• HVAC information
• Water-heating information
• Commercial lighting plans when applicable
• Existing Title 24 documentation
• Building-department correction comments

AES can review the material and identify whether additional information is needed before confirming the project scope.

Can I Get Pricing Before Every Product Has Been Selected?

Potentially.

A project can often be reviewed for quoting before every manufacturer and model number has been finalized.

The plans still need enough information to understand:

• Building type
• Size
• Project scope
• Envelope complexity
• Mechanical approach
• Commercial systems when applicable

If the design changes substantially after the quote is prepared, the scope may need to be reevaluated.

Why Very Cheap Pricing Can Be Misleading

The value of Title 24 work depends on more than generating forms.

A useful analysis should reflect the actual project.

That involves reviewing whether:

• The floor area is correct
• The climate zone is correct
• The windows match the plans
• The insulation matches the sections
• The HVAC information is current
• The water heating is represented correctly
• Commercial lighting matches the electrical design

A low advertised number may not tell you:

• What building type it applies to
• How much plan review is included
• Whether revisions are included
• Whether correction support is included
• Whether the advertised service fits your project at all

The scope behind the price matters.

The Lowest Price Is Not Always the Lowest Project Cost

Energy documentation that is incomplete or poorly coordinated can create additional work elsewhere in the project.

Potential consequences can include:

• Architectural revisions
• Repeated calculations
• Incorrect product orders
• Mechanical changes
• Building-department corrections

That does not mean a higher fee automatically guarantees better work.

It means the quote should be evaluated according to what is actually included and whether the service matches the project.

Can Early Energy Review Help Control Costs?

It can help reduce avoidable redesign.

Starting before all major products have been purchased gives the project team time to resolve questions involving:

• Windows
• Insulation
• HVAC
• Water heating
• Commercial lighting

Changes are generally easier to consider while the project is still on paper than after materials and equipment have been ordered.

What Is Typically Involved in Preparing the Calculations?

Although every project differs, the process can include:

1. Reviewing the Project Scope

AES determines whether the work involves new construction, an ADU, addition, remodel, multifamily project, commercial tenant improvement, HVAC project, lighting project, or another scope.

2. Reviewing the Plans

The building geometry and energy-related features are identified.

3. Identifying Missing Information

AES can determine whether additional window, insulation, mechanical, water-heating, or lighting information is needed.

4. Preparing the Applicable Analysis

The project is evaluated through the appropriate energy-compliance method.

5. Preparing Compliance Documentation

Applicable forms are created from the project analysis.

6. Coordinating the Results With the Plans

The energy measures should correspond to the construction drawings.

The amount of work required at each stage can affect the project fee.

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides professional Title 24 calculations, energy-compliance documentation, 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 buildings
• Commercial construction
• Office tenant improvements
• Retail projects
• Restaurant projects
• Warehouse alterations
• HVAC projects
• Commercial lighting projects
• Energy-related plan-check corrections

AES bases pricing on the actual project rather than pretending every building requires exactly the same amount of analysis.

Learn more through the About Us page or review company background on the clients page.

Get a Project-Specific Quote for Title 24 Calculations

Call (626) 365-1518 | Alternative Energy Systems

The most accurate answer to How Much Do Title 24 Calculations Cost is based on the project itself.

Pricing can change according to:

• Project type
• Building size
• Complexity
• Plan completeness
• Compliance method
• Mechanical and lighting systems
• Requested turnaround
• Revisions
• Plan-check corrections

Rather than applying one price to every building, Alternative Energy Systems can review the project information and provide a quote based on the work actually required.

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

You can also review Title 24 report pricing in California for additional pricing information.

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

Frequently Asked Questions: How Much Do Title 24 Calculations Cost?

How Much Do Title 24 Calculations Cost?

Pricing depends on project type, size, complexity, available documentation, turnaround requirements, and whether revisions are needed. AES provides project-specific pricing rather than one universal fee for every project.

Is there one flat price for every Title 24 calculation?

No. A new home, ADU, addition, multifamily project, commercial building, or tenant improvement can involve very different amounts of work.

Does square footage determine the price?

It is one factor, but complexity, systems, plan completeness, and compliance method can also affect pricing.

Can a small project cost more than a larger project?

Potentially. A smaller but complicated or poorly documented project can require more coordination than a larger straightforward design.

Does a new house cost the same as an ADU?

Not necessarily. The quote depends on each project’s size, design, systems, documentation, and compliance requirements.

Does a detached ADU cost the same as a garage conversion?

Not automatically. A detached ADU and conversion involve different existing conditions and analysis scopes.

Does an addition cost less than a complete new house?

It can involve a different amount of work, but the actual price depends on the addition’s size, complexity, compliance path, and interaction with the existing building.

Does a remodel always need expensive calculations?

No. The required work depends on which energy-regulated components are being altered and which compliance method applies.

Do commercial calculations cost more than residential calculations?

Commercial projects can involve additional systems such as lighting and controls, but pricing depends on the actual project rather than building category alone.

Does multifamily work have different pricing?

It can. Multifamily buildings can involve multiple units, common areas, central systems, lighting, and other project-specific requirements.

Does performance modeling affect pricing?

Performance modeling can involve detailed building modeling and design evaluation. The scope can differ from a qualifying prescriptive project.

Is prescriptive compliance always cheaper?

Not necessarily. Pricing still depends on project type, documentation, systems, and the work required to complete the applicable forms.

Do incomplete plans affect pricing?

They can. Missing information may require additional coordination or later revisions.

Do revisions cost extra?

Revision pricing depends on the project agreement and extent of the changes. Significant design changes can require additional analysis.

Are unlimited revisions automatically included?

Do not assume so. The project-specific quote should identify the applicable scope and revision terms.

Do building-department corrections cost extra?

That depends on the correction, original scope, and work required. Some comments may involve clarification while others require recalculation or revised forms.

Does changing my windows affect the cost?

Potentially, if the change requires updated calculations or compliance forms.

Does changing HVAC equipment affect the cost?

Potentially. Changes to equipment type or efficiency can require review or recalculation.

Does faster turnaround affect pricing?

Turnaround requirements can be one pricing factor depending on availability, scope, and project complexity.

Is HERS or field verification included in the calculation fee?

Do not assume so. Field verification is separate from preparing the original energy calculations and should be confirmed in the project-specific scope.

Is commercial acceptance testing included?

Do not assume so. Acceptance testing is generally a separate construction-stage activity and should be confirmed separately.

Are building permit fees included?

Governmental permit and plan-check fees are separate from professional energy-calculation services unless a specific agreement states otherwise.

Does paying for calculations guarantee permit approval?

No. The calculations support the energy-compliance portion of the permit application, while the building department reviews the complete project.

What information do you need before quoting?

Current floor plans, elevations, sections, roof plans, window information, insulation details, HVAC information, water-heating information, commercial lighting information when applicable, and existing correction comments are useful.

Can I get a quote before every product has been selected?

Potentially. AES needs enough information to understand the building type, project scope, size, systems, and overall complexity.

Can early review help avoid additional cost?

It can help identify missing information and design conflicts before products are ordered or the permit package is finalized.

Where can I find more pricing information?

Review Title 24 report pricing in California or call AES for project-specific pricing.

How do I request a quote?

Call Alternative Energy Systems at (626) 365-1518 or send the current project plans through the contact page.

When Will I Need Title 24 Calculations?

Call (626) 365-1518 | Alternative Energy Systems

When Will I Need Title 24 Calculations usually becomes an important question when a California construction project creates new conditioned space, changes the building envelope, replaces regulated equipment, or alters another part of the building that is covered by the California Energy Code.

You may need energy-compliance calculations or related Title 24 documentation when planning:

• A new home
• A new commercial building
• An accessory dwelling unit
• A garage conversion
• A residential addition
• A major remodel
• A multifamily project
• A commercial tenant improvement
• An HVAC replacement or mechanical alteration
• A window or building-envelope alteration
• A water-heating change
• A commercial lighting project

The important distinction is that not every project requires the same type of calculation.

Some projects use a performance-based energy analysis prepared with California Energy Commission-approved compliance software. Others can demonstrate compliance through applicable prescriptive forms or system-specific documentation.

The correct approach depends on:

• Building type
• Project scope
• Climate zone
• Existing conditions
• Systems being changed
• Selected compliance method

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 if you have plans and want to determine what calculations or compliance documentation your project will need.

The First Trigger Is Usually New Construction or a Change to Energy-Regulated Work

California’s Building Energy Efficiency Standards apply to applicable newly constructed buildings, additions, and alterations.

That means Title 24 can become relevant long before construction begins.

The need for calculations is often triggered when the proposed work affects:

• Conditioned floor area
• Exterior walls
• Roof or ceiling assemblies
• Floors over unconditioned spaces
• Insulation
• Windows or glazed doors
• Heating and cooling systems
• Duct systems
• Ventilation
• Water heating
• Commercial lighting
• Lighting controls

The earlier these components enter the project, the earlier it can make sense to evaluate Title 24 requirements.

When Should I Start Thinking About Title 24 Calculations?

Ideally, energy compliance should be considered while the plans are still being developed rather than immediately before permit submission.

Early calculations can reveal whether the design needs clarification involving:

• Window performance
• Insulation assemblies
• Roof construction
• HVAC efficiency
• Duct locations
• Water heating
• Commercial lighting

Discovering an issue while the plans are still editable can be much easier than discovering it after specifications have been finalized or products have already been ordered.

You Do Not Always Need to Wait Until the Plans Are 100% Finished

AES can often begin reviewing a developing project before every specification has been finalized.

An early review can identify:

• What information is already sufficient
• What information is missing
• Which systems need to be selected
• Which plan details need clarification
• Which decisions may affect the energy analysis

Final calculations still require enough information to accurately describe the proposed building.

The goal is to start early enough to identify problems without finalizing a report around assumptions that will immediately change.

When Will I Need Title 24 Calculations for a New Home?

New residential construction is subject to applicable California Energy Code requirements.

Depending on the compliance method, a new home can require analysis of:

• Building orientation
• Conditioned floor area
• California climate zone
• Exterior walls
• Roof and ceiling assemblies
• Floors
• Insulation
• Window quantity and size
• Window U-factor
• Solar heat gain coefficient
• HVAC systems
• Ducts
• Ventilation
• Water heating
• Other applicable energy measures

If the performance compliance method is used, approved energy-modeling software evaluates the proposed building against the applicable standard design.

New residential construction is therefore one of the clearest situations where energy-compliance planning should begin before permit submission.

When Will I Need Title 24 Calculations for an ADU?

ADUs commonly trigger Title 24 requirements because they create or convert residential living space.

The exact analysis depends on whether the ADU is:

• A newly constructed detached ADU
• An attached ADU
• A garage conversion
• A conversion of another existing space

A new detached ADU may need to be analyzed as a complete new residential structure.

An attached ADU or conversion can require careful separation of existing and proposed construction.

Relevant information may include:

• Conditioned floor area
• Walls
• Roof construction
• Insulation
• Windows
• HVAC
• Ventilation
• Water heating

For more project-specific information, review ADU Title 24.

When Will I Need Title 24 Calculations for a Garage Conversion?

A garage conversion commonly requires energy-compliance review because the project changes space that may have originally been unconditioned into conditioned living space.

That change can introduce requirements for:

• Exterior wall insulation
• Ceiling or roof insulation
• Floor conditions
• Windows
• Exterior doors
• Heating and cooling
• Ventilation
• Water heating when applicable

The fact that the existing garage already has walls and a roof does not automatically mean those assemblies satisfy the requirements for new conditioned living space.

When Will I Need Title 24 Calculations for an Addition?

A residential addition creates new building area that can affect energy compliance.

Examples include:

• Bedroom additions
• Family-room additions
• Kitchen expansions
• Primary-suite additions
• Second-story additions
• Expanded living areas

The new work can involve:

• New conditioned floor area
• New exterior walls
• New roof or ceiling assemblies
• New windows
• New insulation
• Additional heating and cooling loads
• New or extended ductwork

An addition may use an applicable prescriptive compliance path or a performance approach depending on the project.

Does Every Addition Need a Full Performance Calculation?

No.

This is an important distinction.

California provides prescriptive compliance options for qualifying additions.

Some additions can use applicable Certificate of Compliance forms rather than a complete whole-building performance model.

Other projects may benefit from or require performance analysis because of their size, design, glazing, equipment, or selected compliance strategy.

The project should be reviewed before assuming either that a full model is mandatory or that calculations are unnecessary.

When Will I Need Title 24 Calculations During a Remodel?

The word “remodel” alone does not determine the requirement.

A cosmetic project can be very different from an alteration that changes energy-regulated components.

Energy compliance can become relevant when the remodel changes:

• Windows
• Exterior doors
• Exterior walls
• Insulation
• Roof assemblies
• HVAC equipment
• Duct systems
• Water heating
• Commercial lighting

A limited alteration may use specific prescriptive forms rather than a complete performance calculation.

A more extensive remodel can require broader analysis.

When Will Window Changes Trigger Title 24 Requirements?

Windows can affect energy performance because the Energy Code regulates applicable fenestration characteristics.

Relevant values can include:

• U-factor
• Solar heat gain coefficient
• Window area
• Window orientation

The documentation needed depends on whether the window work is part of:

• New construction
• An addition
• A major remodel
• A more limited alteration

A stand-alone window alteration may not need the same performance model as an entire new house, but applicable Energy Code requirements can still apply.

When Will Insulation Changes Matter?

Changing the building envelope can trigger applicable requirements for:

• Exterior walls
• Roofs
• Ceilings
• Attics
• Floors

When those assemblies are part of a project being analyzed, the insulation values need to be represented accurately.

This becomes particularly important during additions, conversions, major remodels, or performance-based compliance.

When Will Roofing Work Affect Title 24?

Roof alterations can have Energy Code requirements depending on:

• Building type
• Roof construction
• Climate zone
• Roofing characteristics
• Scope of the alteration

Some roofing projects can involve applicable cool-roof or envelope provisions without requiring a complete whole-building performance calculation.

The roof scope should be evaluated before assuming no Title 24 documentation is involved.

When Will I Need Calculations Because of HVAC Work?

HVAC work can trigger energy-compliance requirements even when no building addition is being constructed.

Mechanical alterations can involve:

• Equipment type
• Heating efficiency
• Cooling efficiency
• Heat-pump systems
• Duct systems
• Controls
• Airflow
• Applicable field verification

Some HVAC projects use dedicated alteration forms rather than a full building energy model.

If mechanical equipment is being changed as part of a larger addition or remodel, it can also become an input in the broader project analysis.

When Will Duct Changes Matter?

Ductwork can affect energy performance and applicable verification requirements.

A project may need to address:

• Duct location
• Duct insulation
• Duct sealing
• Airflow
• Extension of existing duct systems

When ducts are added, moved, replaced, or extended, the mechanical scope should be evaluated for applicable Title 24 requirements.

When Will Water-Heating Changes Trigger Energy Requirements?

Water heating is a significant regulated energy use.

A project can involve requirements related to:

• Equipment type
• Energy source
• Efficiency
• Heat-pump water heaters
• Central systems
• Individual systems
• Hot-water distribution

A simple equipment alteration can use different documentation from a new building or major remodel.

If water heating is part of a broader performance analysis, the proposed system needs to be represented accurately.

When Will I Need Title 24 Calculations for a Multifamily Building?

Multifamily construction has dedicated Energy Code requirements.

Calculations or compliance documentation can become necessary for:

• New apartment buildings
• New multifamily developments
• Multifamily additions
• Apartment alterations
• Common-area improvements
• Mechanical-system changes
• Water-heating changes
• Lighting alterations

Multifamily buildings should be classified correctly because their compliance requirements differ from both detached single-family homes and ordinary nonresidential buildings.

When Will I Need Title 24 Calculations for a New Commercial Building?

New nonresidential construction is subject to applicable Energy Code requirements.

Depending on the project, the analysis can involve:

• Building envelope
• Windows and storefront glazing
• Mechanical systems
• Ventilation
• Service water heating
• Interior lighting
• Exterior lighting
• Lighting controls
• Other regulated systems

A project can use an applicable prescriptive or performance compliance method.

Performance compliance for the current Energy Code must use California Energy Commission-approved software.

When Will I Need Title 24 Calculations for a Tenant Improvement?

A commercial tenant improvement can trigger energy requirements even though the building already exists.

Projects can include:

• Office improvements
• Retail build-outs
• Restaurant renovations
• Medical offices
• Service-business spaces
• Warehouse office improvements

The tenant improvement may change:

• Lighting
• Lighting controls
• HVAC equipment
• Ventilation
• Water heating
• Storefront glazing

The previous energy documentation for the shell building should not automatically be assumed to cover the new tenant work.

When Will Commercial Lighting Require Title 24 Documentation?

Commercial lighting alterations can trigger Energy Code requirements.

Depending on the scope, the project may need documentation involving:

• Fixture types
• Fixture quantities
• Lighting power
• Occupancy controls
• Automatic shutoff controls
• Daylighting controls
• Exterior lighting

Lighting-only work does not necessarily require the same whole-building model as new construction.

Applicable nonresidential lighting documentation may still be required.

For professional commercial assistance, review Title 24 compliance services.

How Do I Know Whether I Need Prescriptive or Performance Calculations?

California provides both prescriptive and performance compliance methods.

Prescriptive Compliance

Prescriptive compliance follows applicable requirements established for the building components and systems included in the project.

Depending on the scope, those requirements can address:

• Insulation
• Windows
• Roofs
• HVAC systems
• Water heating
• Lighting
• Other applicable components

Performance Compliance

Performance compliance uses approved computer modeling to evaluate the proposed design against the applicable standard design or energy budget.

This approach can allow qualifying design tradeoffs and may be useful when the building does not follow a straightforward prescriptive configuration.

The project should be evaluated before choosing the compliance approach.

When Will Performance Calculations Be Especially Useful?

Performance modeling can be particularly useful when the project involves:

• Large amounts of glazing
• Unusual building geometry
• Multiple envelope assemblies
• Custom architectural features
• Design tradeoffs
• Complex HVAC systems
• A project that does not fit a simple prescriptive approach

The analysis allows different energy measures to be evaluated together.

For example, a design with more glazing may potentially compensate through other qualifying efficiency improvements.

When Will Prescriptive Forms Be Enough?

Some additions and alterations can demonstrate compliance using applicable prescriptive forms rather than a complete performance model.

The California Energy Commission provides dedicated forms for various types of:

• Residential additions
• Residential alterations
• Space-conditioning alterations
• Other eligible scopes

The exact form depends on the project and whether separate field verification is required.

Prescriptive compliance is still Title 24 compliance.

It should not be confused with an exemption.

Will I Need Calculations Just Because I Need a Building Permit?

Not necessarily in the same form for every project.

A building permit may require:

• A performance energy report
• Prescriptive forms
• Mechanical compliance documents
• Lighting forms
• Other project-specific energy documentation

The building permit itself does not automatically establish that a full whole-building performance model is required.

The construction scope determines the applicable energy documentation.

Can Title 24 Apply Even if I Do Not Need a Full Calculation?

Yes.

This is one of the most important points to understand.

A project can be subject to California’s Energy Code even when a full performance calculation is unnecessary.

For example, an alteration may need to satisfy:

• Mandatory requirements
• Prescriptive requirements
• Equipment requirements
• Installation requirements
• Verification requirements

using project-specific forms instead of a whole-building energy model.

When Might I Not Need a Full Title 24 Calculation?

Depending on the project, a full performance model may not be necessary for:

• Certain limited alterations
• Qualifying prescriptive additions
• Some HVAC-only projects
• Some lighting-only projects
• Some envelope alterations
• True repair work that falls outside applicable alteration requirements

The actual scope should be reviewed before an exemption or limited compliance path is assumed.

A Repair and an Alteration Are Not Always the Same Thing

Calling work a repair does not necessarily determine its Energy Code treatment.

Replacing a regulated component can sometimes constitute an alteration.

Examples can include:

• Window replacement
• HVAC replacement
• Duct replacement
• Water-heater replacement
• Roofing work

The actual work being performed determines which provisions apply.

When Should I Contact AES During the Design Process?

A good time to begin is when the basic building design is developed enough to identify:

• Project scope
• Building size
• Floor plans
• Exterior elevations
• Roof configuration
• Windows
• Envelope assemblies
• Proposed mechanical systems

The plans do not necessarily need every final product model at the first review.

Starting before the permit package is completely finished gives AES an opportunity to identify missing information before it creates a last-minute problem.

Why Waiting Until Permit Submission Can Create Problems

If energy analysis begins only after the architectural plans are considered complete, a compliance issue can force revisions to work that has already been coordinated.

Potential changes can involve:

• Window specifications
• Insulation
• Roof details
• HVAC equipment
• Mechanical notes
• Commercial lighting

Beginning earlier can give the architect, owner, contractor, and energy consultant more flexibility to resolve those questions.

When Do Calculations Need to Be Revised?

Title 24 calculations should be reviewed when the project changes an energy-related feature represented in the existing analysis.

Examples include:

• Increasing or decreasing conditioned floor area
• Changing room configuration
• Adding or removing windows
• Changing window performance
• Changing insulation
• Changing the roof assembly
• Changing HVAC equipment
• Changing duct locations
• Changing ventilation
• Changing water heating
• Changing commercial lighting

The significance of the revision depends on the extent of the design change.

Will I Need New Calculations After Building Department Corrections?

Sometimes.

A building-department correction may simply ask for clarification.

Another correction may identify a design conflict requiring a recalculation.

Energy-related comments can involve:

• Incorrect or missing forms
• Incorrect climate zone
• Floor-area discrepancies
• Window discrepancies
• Insulation discrepancies
• Mechanical changes
• Lighting-control information
• Differences between the report and plans

Send AES the complete correction notice and latest plans so the actual issue can be evaluated.

Will I Need New Calculations if My Contractor Changes Equipment?

Potentially.

A product substitution should be reviewed when it changes a value or system represented in the energy documentation.

Examples include:

• A different HVAC unit
• Different windows
• A different water heater
• A different insulation assembly
• A changed roof specification

A replacement product that performs the same basic function is not automatically equivalent for energy-compliance purposes.

Will I Need New Calculations if My Plans Change After Permit Approval?

A significant post-permit design change can require revised calculations and approval by the authority having jurisdiction.

The project should continue to correspond to the approved energy documentation during construction.

Notify the project team before making substantial changes to:

• Windows
• Insulation
• HVAC equipment
• Ductwork
• Water heating
• Commercial lighting
• Other modeled building features

What Energy Code Applies to Projects Now?

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

When the performance compliance method is used, the project must use California Energy Commission-approved software for the applicable 2025 Energy Code building category and project scope.

For official information, review the California Energy Commission 2025 Energy Code Compliance Software information.

The Permit Date Can Determine Which Code Cycle Applies

California updates the Energy Code on a three-year cycle.

The applicable code edition can depend on the permit circumstances.

Projects beginning under one code cycle should not automatically be converted to another simply because the calendar year changes.

If a project spans a code transition, confirm the applicable code edition with the building department and provide AES with any permit information already available.

What Should I Send Before Requesting Calculations?

The exact information depends on the project.

Useful documents can include:

• Floor plans
• Exterior elevations
• Building sections
• Roof plans
• Window schedules
• Window-performance information
• Insulation details
• HVAC specifications
• Duct-location information
• Ventilation information
• Water-heating specifications
• Commercial lighting plans when applicable
• Commercial lighting-control information when applicable
• Existing energy documentation
• Building-department correction comments

Not every project requires every item.

AES can review the available information and identify what is still needed.

Before sending files, review what AES will need from you.

What Happens After I Send My Plans?

The process generally begins by identifying the actual scope of work.

1. Determine the Project Type

AES identifies whether the project involves new construction, an ADU, addition, conversion, remodel, multifamily project, commercial tenant improvement, or another applicable scope.

2. Determine the Applicable Compliance Method

The project is reviewed to determine whether prescriptive documentation, performance calculations, or another applicable compliance path is appropriate.

3. Review the Plans and Specifications

Energy-related features of the proposed building are identified.

4. Identify Missing Information

AES can identify unanswered questions involving windows, insulation, mechanical systems, water heating, or other required project information.

5. Prepare the Applicable Analysis

The energy analysis or prescriptive documentation is prepared according to the project.

6. Coordinate the Results With the Plans

The applicable energy measures should agree with the construction documents before permit submission.

For more information about the technical process, review Title 24 energy calculations.

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides 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 buildings
• Mixed-use projects
• Commercial construction
• Office tenant improvements
• Retail projects
• Restaurant projects
• Warehouse alterations
• HVAC projects
• Commercial lighting projects
• Energy-related plan-check corrections

AES evaluates the actual construction scope rather than assuming every project needs the same type of report.

Learn more through the About Us page or review company background on the clients page.

Find Out When Your Project Will Need Title 24 Calculations

Call (626) 365-1518 | Alternative Energy Systems

The best answer to When Will I Need Title 24 Calculations depends on what you plan to build or change.

Energy compliance commonly becomes relevant when your project involves:

• New conditioned space
• A new residential or commercial building
• An ADU
• A garage conversion
• An addition
• Energy-related remodeling
• Window or envelope changes
• HVAC or duct changes
• Water-heating changes
• Commercial lighting
• A multifamily project
• A commercial tenant improvement

The project may need a complete performance calculation, prescriptive compliance documentation, system-specific forms, or a combination of requirements.

The most effective time to determine that is before permit submission and before major energy-related products are ordered.

Alternative Energy Systems can review your plans and determine what information is needed for the applicable compliance path.

Call (626) 365-1518 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: When Will I Need Title 24 Calculations?

When Will I Need Title 24 Calculations?

You can need Title 24 calculations or related energy-compliance documentation when a California project involves applicable new construction, additions, alterations, conversions, or regulated energy-related building systems.

Do I need calculations for a new house?

New residential construction is subject to applicable Energy Code requirements and requires the appropriate compliance documentation.

Do I need calculations for an ADU?

Applicable ADUs require energy-compliance documentation. The exact method depends on whether the ADU is new, attached, detached, or created from existing space.

Do I need calculations for a garage conversion?

Garage conversions commonly require energy-compliance review because previously unconditioned space is being converted into conditioned living space.

Do I need calculations for an addition?

Applicable additions must comply with the Energy Code. Depending on the project, compliance may use a prescriptive or performance method.

Does a small addition require a full performance model?

Not necessarily. Some qualifying additions can use applicable prescriptive compliance forms.

Do I need calculations for a remodel?

Possibly. Remodels that alter windows, envelope assemblies, HVAC, ducts, water heating, roofing, commercial lighting, or other regulated systems can trigger applicable requirements.

Do replacement windows trigger Title 24?

Applicable window alterations can be subject to Energy Code requirements even when a complete whole-building performance model is unnecessary.

Does new insulation trigger Title 24?

Alterations to regulated envelope assemblies can be subject to applicable insulation and energy requirements.

Does reroofing trigger Title 24?

Roof alterations can have Energy Code requirements depending on building type, roof characteristics, climate zone, and project scope.

Will I need calculations when replacing HVAC equipment?

Mechanical alterations can trigger equipment, duct, control, and verification requirements. Some HVAC projects use specific alteration forms rather than a complete building model.

Will ductwork trigger Title 24?

Applicable duct additions or alterations can trigger requirements involving sealing, insulation, airflow, location, or field verification.

Will replacing a water heater trigger Title 24?

Applicable water-heating alterations can have Energy Code requirements depending on building type, equipment, and project scope.

Will a commercial tenant improvement need Title 24 calculations?

It can. Lighting, HVAC, ventilation, water heating, glazing, and other altered systems can trigger nonresidential requirements.

Will commercial lighting require Title 24 documentation?

Applicable commercial lighting alterations can require lighting-power and control documentation even without a whole-building performance model.

Will multifamily construction require Title 24 calculations?

Applicable new multifamily construction, additions, and alterations are subject to dedicated multifamily Energy Code requirements.

Does every building permit require a full Title 24 calculation?

No. Some permit scopes use prescriptive or system-specific compliance forms instead.

Can Title 24 apply even when I do not need a full energy model?

Yes. Mandatory, prescriptive, installation, or verification requirements can still apply.

What is prescriptive compliance?

Prescriptive compliance follows applicable component and system requirements established by the Energy Code.

What is performance compliance?

Performance compliance uses approved computer modeling to compare the proposed building with the applicable standard design or energy budget.

When is performance modeling useful?

It can be useful for new construction, complex projects, unusual glazing, design tradeoffs, or projects that do not fit a straightforward prescriptive approach.

When should I order Title 24 calculations?

It is generally best to begin energy review before the permit plans are considered completely final and before major energy-related products are purchased.

Can calculations begin before my plans are finished?

Preliminary review can begin with available drawings, but final calculations require enough information to accurately represent the proposed project.

Will I need revised calculations if my plans change?

Potentially. Changes to floor area, windows, insulation, roofing, HVAC, ducts, water heating, lighting, or other analyzed features can require revision.

Will I need revised calculations after plan-check corrections?

Sometimes. It depends on whether the correction requires clarification or an actual change to the analyzed project.

Will changing HVAC equipment require new calculations?

The report should be reviewed when substituted equipment changes an energy characteristic used in the existing analysis.

What Energy Code applies now?

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

Do performance calculations require approved software?

Yes. Performance compliance must use software approved by the California Energy Commission for the applicable code cycle, building type, and project scope.

What should I send AES first?

Current floor plans, elevations, sections, roof plans, window information, insulation details, HVAC specifications, water-heating information, commercial lighting information when applicable, and existing correction comments are useful starting documents.

How do I find out exactly what my project needs?

Call Alternative Energy Systems at (626) 365-1518 and provide the current plans and proposed construction scope for review.

Why Do I Need Title 24 Calculations?

Call (626) 365-1518 | Alternative Energy Systems

Why Do I Need Title 24 Calculations is a practical question when architectural plans already show the building, windows, walls, roof, rooms, and equipment locations.

The reason is that construction drawings describe what you intend to build, while Title 24 calculations evaluate how the energy-related parts of that design work together under California’s Building Energy Efficiency Standards.

Depending on the project, the calculations can evaluate:

• Building size
• Conditioned floor area
• Building orientation
• California climate zone
• Exterior wall assemblies
• Roof and ceiling assemblies
• Floor assemblies
• Insulation
• Window area
• Window performance
• Glazed exterior doors
• HVAC equipment
• Duct systems
• Ventilation
• Water heating
• Commercial lighting and controls when applicable
• Other regulated building systems

The calculations help determine whether the proposed energy design satisfies the applicable compliance path or whether changes should be considered before the permit documents are finalized.

They also create a technical basis for the compliance forms submitted with the construction plans.

Alternative Energy Systems brings more than 30 years of California energy-compliance experience to residential, multifamily, mixed-use, and commercial projects.

Call (626) 365-1518 if you need calculations prepared for a current project or need existing energy documentation reviewed.

Title 24 Calculations Turn Building Plans Into Measurable Energy Compliance

A set of architectural plans can show that a wall contains insulation or that a building has energy-efficient windows.

That does not necessarily establish whether the complete proposed design satisfies the applicable California Energy Code requirements.

The calculations place measurable values behind those design decisions.

For example, they can consider:

• How much glazing the building has
• Where that glazing is located
• How efficiently the glazing performs
• How much insulation is included in different assemblies
• What HVAC system serves the building
• Where ducts are located
• How water is heated
• How the complete design performs in the applicable climate zone

That information provides a more complete picture than looking at any one component by itself.

Why Can’t the Building Department Just Look at the Plans?

Some energy characteristics cannot be determined from architectural drawings alone.

Two windows that look identical on an elevation may have different:

• U-factors
• Solar heat gain coefficients

Two HVAC units that occupy the same space can have different efficiencies.

Two wall assemblies can look similar on a floor plan while using different insulation values or construction methods.

The calculations organize these technical characteristics so the applicable energy requirements can be evaluated consistently.

What Do Title 24 Calculations Actually Prove?

The calculations are used to demonstrate how a particular project addresses the applicable Energy Code.

Depending on the compliance method, that can mean showing that:

• Applicable mandatory requirements are addressed
• Prescriptive requirements are satisfied
• The proposed design meets the applicable performance requirements

For performance compliance, approved software evaluates the proposed building against the applicable standard design.

The purpose is not simply to generate a pass/fail label.

The calculation identifies the energy-related characteristics that make up the compliant design.

Performance Calculations Allow Building Features to Work Together

One of the major benefits of performance compliance is the ability to evaluate the building as a system.

A project does not necessarily succeed or fail because of one component alone.

For example, a building with a large amount of glazing may potentially improve performance elsewhere through measures involving:

• Better window specifications
• Improved insulation
• More efficient HVAC equipment
• Roof improvements
• Other qualifying energy measures

The calculation evaluates the interaction among those features.

This can provide more design flexibility than treating every building component independently.

Prescriptive Compliance Is Different From Performance Calculations

Not every project requires a full performance model.

California also allows applicable projects to demonstrate compliance through prescriptive requirements.

Under a prescriptive approach, the project follows specific requirements established for applicable components and systems.

Depending on the scope, that can involve:

• Insulation levels
• Window performance
• Roof requirements
• HVAC efficiency
• Water heating
• Lighting requirements
• Other applicable measures

The appropriate compliance method depends on the project.

A smaller alteration may need limited prescriptive documentation, while a new home or more complex project may benefit from performance analysis.

Not Every Project Needs the Same Type of Calculation

The amount and type of analysis depend on:

• Building classification
• Project scope
• Climate zone
• Whether the work is new construction
• Whether the work is an addition
• Whether the work is an alteration
• Systems being modified
• Selected compliance method

That is why one energy report should not simply be copied from another project.

Climate Zone Is an Important Part of the Calculation

California uses 16 building climate zones.

Performance budgets and certain prescriptive requirements vary according to climate zone and building type.

This matters because buildings in different parts of California experience different:

• Heating loads
• Cooling loads
• Outdoor temperatures
• Solar conditions
• Seasonal energy demands

The calculation therefore needs the correct project location and climate-zone information.

Why Building Orientation Matters

Orientation affects how the building interacts with the sun.

Windows facing different directions can receive different amounts of solar exposure.

For projects using performance analysis, the relationship among:

• North-facing glazing
• South-facing glazing
• East-facing glazing
• West-facing glazing

can influence the modeled building performance.

This is one reason the calculation needs an actual project plan instead of only a total square-foot number.

Window Area Can Have a Significant Effect on the Calculation

Windows are an important part of the building envelope.

The analysis may consider:

• Total window area
• Window size
• Window orientation
• U-factor
• Solar heat gain coefficient
• Glazed exterior doors

A building with extensive glazing may perform differently from another building of similar size with much less glass.

That difference needs to be reflected in the energy analysis.

Why Window U-Factor Is Included

U-factor describes thermal performance associated with a window or glazed assembly.

Lower heat transfer through glazing can influence overall building performance.

The value used in the energy calculation should correspond to the product eventually selected for the project.

If the contractor later substitutes a window with different performance values, the energy documentation may need review.

Why Solar Heat Gain Coefficient Is Included

Solar heat gain coefficient relates to the amount of solar energy passing through glazing.

That can affect cooling performance, particularly where solar exposure is significant.

The effect also interacts with:

• Window orientation
• Window area
• Climate zone
• Overall building design

This is another reason the calculations evaluate the complete project rather than simply verifying that windows are labeled energy efficient.

Insulation Is Evaluated as Part of the Complete Envelope

Title 24 calculations can incorporate insulation associated with:

• Exterior walls
• Roofs
• Ceilings
• Attics
• Floors
• Other thermal boundaries

Different assemblies can have different energy characteristics.

The architectural sections and energy calculations should therefore describe compatible construction.

Roof Construction Can Affect Energy Performance

The roof is exposed to outdoor temperatures and solar conditions.

Depending on the project, calculations can consider:

• Roof insulation
• Ceiling insulation
• Attic configuration
• Roofing characteristics
• Applicable cool-roof measures

A roof design should not be changed after the report is completed without checking whether that change affects the energy documentation.

HVAC Efficiency Is Part of the Energy Analysis

Heating and cooling equipment can be a major part of building energy use.

Calculations may include information involving:

• System type
• Heating efficiency
• Cooling efficiency
• Heat-pump systems
• Number of systems
• Controls
• Duct configuration

If the mechanical design changes after the original calculation, the report may require review.

Duct Location Can Change the Result

Duct systems located inside conditioned space can interact with the building differently from ducts located in:

• Attics
• Crawlspaces
• Garages
• Other unconditioned areas

The energy analysis should reflect the actual proposed duct configuration rather than an assumption that is later changed during construction.

Ventilation Must Be Coordinated With the Mechanical Design

Energy-efficient buildings also need appropriate ventilation.

Depending on the building type and scope, the analysis and compliance documentation can involve:

• Whole-building ventilation
• Local exhaust
• Outdoor-air systems
• Other applicable ventilation measures

The energy report should remain coordinated with the mechanical plans.

Water Heating Can Affect the Calculations

Water heating is another important building energy use.

The analysis may include:

• Equipment type
• Energy source
• Efficiency
• Heat-pump water heating
• Central systems
• Individual systems
• Other applicable characteristics

Changing the water-heating system after the calculations are completed can affect the compliance package.

Commercial Projects Can Require Lighting Calculations

For nonresidential projects, Title 24 calculations can also address commercial lighting.

Depending on the project, this may involve:

• Fixture types
• Fixture quantities
• Fixture wattage
• Space use
• Lighting power
• Lighting controls
• Daylighting controls
• Exterior lighting

Commercial lighting documentation should match the electrical and architectural drawings.

Title 24 Calculations Help Identify Problems Before Plan Check

The calculations are valuable before permit submission because they can reveal incomplete or conflicting project information.

AES may identify questions such as:

• Does the conditioned floor area match throughout the plans?
• Are all windows shown in the schedule?
• Have window-performance values been identified?
• Do the wall sections identify insulation?
• Is the roof assembly complete?
• Has the HVAC equipment been selected?
• Are duct locations shown?
• Is the water-heating system clear?
• Are commercial lighting schedules complete?

Resolving those issues before formal plan review can reduce preventable corrections.

The Calculations Help Coordinate the Report With the Plans

One of the most common sources of permit problems is a disagreement between the energy documentation and the construction drawings.

Examples include:

• The report shows one floor area while the plans show another
• The report uses one window specification while the schedule lists another
• The report assumes one insulation assembly while the section shows another
• The report uses one HVAC system while the mechanical plan shows another

A correct calculation based on outdated plans can still create problems.

The report and drawings need to describe the same current design.

The Calculations Can Identify Which Specifications Need to Be on the Plans

Once the compliant design is established, the project team can identify which energy-related specifications need to remain part of the final construction documents.

These may include:

• Window-performance requirements
• Insulation values
• Roof characteristics
• Mechanical efficiencies
• Duct requirements
• Water-heating specifications
• Commercial lighting measures

This gives the architect and contractor clearer information about what must be preserved during construction.

The Calculations Can Help With Product Selection

Calculations can influence decisions before products are purchased.

For example, the project team can compare proposed:

• Windows
• HVAC systems
• Water heaters
• Insulation assemblies
• Other energy-related products

against the assumptions in the energy documentation.

That can help reduce the risk of purchasing something that conflicts with the approved design.

They Can Also Reveal Design Tradeoffs

Performance analysis can be useful when the design team wants to preserve an architectural feature that does not follow a simple prescriptive approach.

For example, the project might prioritize:

• More glazing
• A particular window configuration
• A certain roof design
• A preferred mechanical system

The energy model can help determine whether qualifying improvements elsewhere in the design can support the proposed configuration.

The final solution still needs to comply with mandatory requirements and the applicable performance rules.

Why Do I Need Title 24 Calculations for a New Home?

New residential construction needs to address the applicable California Energy Code requirements.

A whole-building analysis can evaluate how the home’s:

• Geometry
• Orientation
• Envelope
• Glazing
• Insulation
• HVAC
• Duct systems
• Ventilation
• Water heating

work together.

The calculations then provide the technical basis for the applicable compliance forms.

Why Do I Need Title 24 Calculations for an ADU?

ADUs can require energy-compliance analysis whether they are:

• New detached structures
• Attached additions
• Garage conversions
• Conversions of other existing spaces

A detached ADU may need to be evaluated as a complete new residential structure.

A conversion may require the analysis to distinguish existing construction from the new conditioned space.

For additional information, review ADU Title 24.

Why Do I Need Title 24 Calculations for an Addition?

An addition introduces new conditioned space and new envelope components.

The project may add:

• Exterior walls
• Roof area
• Windows
• Insulation
• Heating and cooling loads

Depending on the project, compliance may be demonstrated through a prescriptive or performance method.

The calculations or applicable forms establish which requirements apply to the proposed addition.

Why Do I Need Title 24 Calculations for a Garage Conversion?

A garage conversion can change unconditioned space into conditioned living space.

The project may need to address:

• Existing wall construction
• New wall insulation
• Ceiling or roof insulation
• Floor conditions
• Windows
• HVAC
• Ventilation

The analysis helps define what the converted space needs to include as part of the current design.

Why Do I Need Title 24 Calculations for a Remodel?

Not every remodel requires the same analysis.

However, energy compliance can become relevant when the project changes:

• Windows
• Exterior walls
• Insulation
• Roofing
• HVAC systems
• Ducts
• Water heating
• Commercial lighting

A limited alteration may use prescriptive or system-specific documentation instead of a full whole-building performance calculation.

Why Do I Need Title 24 Calculations for a Multifamily Project?

Multifamily buildings have their own applicable Energy Code requirements and compliance documentation.

The analysis can involve:

• Dwelling units
• Common areas
• Envelope systems
• Central mechanical systems
• Individual mechanical systems
• Water heating
• Lighting
• Other applicable features

The project should be classified correctly before the calculations are prepared.

Why Do I Need Title 24 Calculations for a Commercial Project?

Commercial projects can involve several interacting energy systems.

Depending on the project, the analysis may evaluate:

• Building envelope
• Storefront glazing
• Mechanical systems
• Ventilation
• Service water heating
• Interior lighting
• Exterior lighting
• Lighting controls

Commercial projects can also involve coordination among architects, mechanical engineers, electrical designers, lighting designers, contractors, and property owners.

For related professional services, review Title 24 compliance services and Title 24 energy analysis.

Do Title 24 Calculations Guarantee Permit Approval?

No.

The calculations support the energy-compliance portion of a permit package.

A building department may also review:

• Architectural requirements
• Structural requirements
• Electrical requirements
• Mechanical requirements
• Plumbing requirements
• CALGreen requirements
• Fire and life-safety requirements
• Other applicable codes

A properly prepared energy analysis does not guarantee approval of the entire construction project.

Can the Building Department Require Revised Calculations?

Yes.

Revisions may be necessary when:

• The plans change
• The conditioned floor area changes
• Windows change
• Insulation changes
• The roof design changes
• HVAC equipment changes
• Water heating changes
• Commercial lighting changes
• The building department identifies incomplete or inconsistent information

The revised calculations should reflect the actual current project rather than simply modifying isolated numbers.

Do Calculations Need to Be Updated if the Contractor Changes Equipment?

Potentially.

If a product substitution changes an input used in the approved analysis, the existing documentation should be reviewed.

This can include changes to:

• Windows
• HVAC systems
• Water heaters
• Insulation assemblies
• Other modeled or specified components

A substitution that appears equivalent by size or function is not necessarily equivalent for energy compliance.

Can I Reuse Title 24 Calculations From Another Project?

No project-specific energy calculation should automatically be reused for a different building.

The analysis can depend on:

• Address
• Climate zone
• Building type
• Floor area
• Geometry
• Orientation
• Windows
• Envelope construction
• Mechanical systems
• Water heating

Two similar-looking buildings can therefore produce different energy results.

Can I Reuse Old Calculations From the Same Building?

Old calculations can sometimes provide useful background, but they should not automatically be submitted for new work.

The previous analysis may reflect:

• An older Energy Code cycle
• An earlier project scope
• Old windows
• Old HVAC equipment
• Different floor area
• Different construction plans

AES can review the old report together with the current plans.

The Current Energy Code Requires Current Compliance Methods

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

When the performance compliance method is used, approved 2025 compliance software is required.

CEC-approved software evaluates the proposed project using the modeling rules established for the current Energy Code.

For official information about current compliance software, review the California Energy Commission 2025 Energy Code Compliance Software page.

What Information Is Needed Before Calculations Can Be Completed?

Helpful project documents can include:

• Floor plans
• Exterior elevations
• Building sections
• Roof plans
• Window schedules
• Window specifications
• Insulation information
• HVAC specifications
• Duct-location information
• Ventilation information
• Water-heating information
• Commercial lighting plans when applicable
• Commercial lighting-control information when applicable
• Existing energy reports
• Building-department correction comments

Not every project requires every item.

AES can review what is available and identify missing information.

Before submitting documents, review what AES will need from you.

How Are Title 24 Calculations Prepared?

The process begins with the actual project rather than a generic template.

1. Identify the Project Scope

AES determines whether the project involves new construction, an ADU, addition, conversion, alteration, multifamily project, commercial tenant improvement, HVAC work, lighting work, or another applicable scope.

2. Review the Plans

The building geometry, envelope, windows, mechanical systems, and other applicable information are reviewed.

3. Confirm the Climate Zone and Building Classification

The correct project location and building type are important inputs.

4. Identify Missing Information

Incomplete specifications or conflicting plan information are identified before final analysis.

5. Complete the Applicable Compliance Analysis

The project is evaluated through the applicable prescriptive or performance compliance method.

6. Prepare the Compliance Documentation

The resulting forms identify the energy measures associated with the proposed design.

7. Coordinate the Results With the Plans

The final energy requirements should agree with the current construction drawings.

Why Early Calculations Can Make the Design Process Easier

Starting before the plans are completely finalized gives the project team time to address energy issues while design decisions are still flexible.

Early review can identify:

• Glazing that affects performance
• Missing insulation requirements
• Mechanical-system questions
• Roof-performance issues
• Incomplete lighting information
• Other energy-related conflicts

Waiting until immediately before permit submission can turn ordinary design decisions into last-minute plan revisions.

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides professional Title 24 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 residential construction
• ADUs
• Garage conversions
• Additions
• Residential remodels
• Multifamily projects
• Mixed-use buildings
• Commercial construction
• Office tenant improvements
• Retail projects
• Restaurant projects
• Warehouse alterations
• HVAC projects
• Commercial lighting projects
• Energy-related plan-check corrections

AES prepares calculations using the actual building plans and available specifications so the resulting documentation corresponds to the project being permitted.

Learn more through the About Us page or review company background on the clients page.

Get Title 24 Calculations Based on Your Actual Project

Call (626) 365-1518 | Alternative Energy Systems

Understanding Why Do I Need Title 24 Calculations comes down to one central point:

California energy requirements must be applied to the actual building being designed.

The calculations provide a way to evaluate how the proposed:

• Building geometry
• Climate zone
• Envelope
• Windows
• Insulation
• Roof
• HVAC systems
• Ducts
• Ventilation
• Water heating
• Commercial lighting when applicable

work together under the applicable compliance method.

They also create the technical basis for energy-compliance documentation that can be coordinated with the permit drawings.

Alternative Energy Systems can review your plans, identify the information needed, prepare the applicable calculations, and assist with energy-related revisions or plan-check comments.

Call (626) 365-1518 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: Why Do I Need Title 24 Calculations?

Why Do I Need Title 24 Calculations?

They evaluate the energy-related characteristics of a California building project and provide the technical basis for demonstrating compliance with the applicable Energy Code requirements.

Are Title 24 calculations the same as architectural plans?

No. Architectural plans describe the proposed construction, while energy calculations evaluate energy-related features within that design.

What do the calculations evaluate?

Depending on the project, they can evaluate building geometry, climate zone, orientation, windows, insulation, roofs, HVAC, ducts, ventilation, water heating, lighting, and other applicable systems.

Why does conditioned floor area matter?

Conditioned floor area helps define the building space being heated or cooled and is an important project characteristic in energy analysis.

Why does climate zone matter?

California uses 16 building climate zones, and performance budgets and certain prescriptive requirements vary according to climate zone and building type.

Why does building orientation matter?

Orientation can affect solar exposure through windows and therefore influence building heating and cooling performance.

Why are windows included?

Window area, orientation, U-factor, solar heat gain coefficient, and other fenestration characteristics can significantly affect building energy performance.

Why is insulation included?

Insulation affects heat transfer through walls, roofs, ceilings, floors, and other parts of the thermal envelope.

Why is HVAC included?

Heating and cooling systems are major energy users, and equipment type, efficiency, ducts, and controls can affect compliance.

Why are ducts included?

Duct location, sealing, insulation, airflow, and other conditions can affect mechanical-system energy performance.

Why is ventilation included?

Applicable ventilation systems need to be coordinated with mechanical design and Energy Code requirements.

Why is water heating included?

Water heating is a significant building energy use and can affect the applicable compliance analysis.

Why is commercial lighting included?

Nonresidential Energy Code compliance can regulate lighting power, fixture wattage, controls, daylighting, and other lighting measures.

Do all projects need performance calculations?

No. Some projects can comply through applicable prescriptive requirements or system-specific forms rather than whole-building performance modeling.

What is performance compliance?

Performance compliance uses approved energy-modeling software to compare a proposed building against the applicable standard design or energy budget.

What is prescriptive compliance?

Prescriptive compliance follows specific component and system requirements established by the Energy Code.

Can calculations provide design flexibility?

Performance analysis can allow qualifying energy-efficiency tradeoffs among different building features while still satisfying applicable mandatory and performance requirements.

Do new homes need Title 24 calculations?

New homes are subject to applicable Energy Code requirements. The exact calculations and forms depend on the compliance method.

Do ADUs need Title 24 calculations?

Applicable ADUs require energy-compliance documentation based on whether they are detached, attached, or conversions and on the selected compliance method.

Do additions require calculations?

Applicable additions require Energy Code compliance, which may be demonstrated through a prescriptive or performance method depending on the project.

Do garage conversions require calculations?

They commonly require energy-compliance review because unconditioned space is being converted into conditioned living space.

Do remodels require calculations?

Some do. Alterations affecting regulated energy components can require prescriptive, performance, or system-specific compliance documentation.

Do commercial tenant improvements need calculations?

They can. Lighting, mechanical systems, ventilation, water heating, glazing, and other altered systems can trigger nonresidential Energy Code requirements.

Can Title 24 calculations reduce plan-check problems?

Accurate, coordinated calculations can help identify missing or conflicting energy information before submittal, although they cannot guarantee that the building department will issue no corrections.

Do Title 24 calculations guarantee permit approval?

No. Energy compliance is only one portion of the complete building permit review.

Can calculations be revised?

Yes. Revisions may be necessary when energy-related features of the design change.

Do calculations need to match the plans?

Yes. The energy analysis and construction drawings should represent the same current project.

Can I reuse calculations from another project?

No project-specific analysis should automatically be reused. Address, climate zone, floor area, orientation, windows, envelope, and building systems can all differ.

Can I reuse old calculations from the same property?

They may provide background, but the applicable code cycle, construction scope, plans, and building systems should be reviewed before reuse.

What Energy Code is currently used?

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

What software is used for performance compliance?

Performance calculations under the current code must use software approved by the California Energy Commission for the applicable building type and project scope.

What should I send AES to begin?

Current floor plans, elevations, sections, roof plans, window information, insulation details, HVAC specifications, water-heating information, commercial lighting information when applicable, and any existing correction comments are useful starting documents.

How do I get started?

Call Alternative Energy Systems at (626) 365-1518 and provide the current project plans for review.

When Is a Title 24 Energy Report Required?

Call (626) 365-1518 | Alternative Energy Systems

When Is a Title 24 Energy Report Required depends on the building type, construction scope, systems being changed, and the method used to demonstrate compliance with California’s Building Energy Efficiency Standards.

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

The Energy Code applies broadly to:

• Newly constructed residential buildings
• Newly constructed multifamily buildings
• Newly constructed nonresidential buildings
• Additions to existing buildings
• Alterations to existing buildings

However, that does not mean every project requires the same type of full performance-based energy report.

Depending on the project, compliance may be demonstrated through:

• A performance-based Title 24 energy analysis
• Prescriptive compliance forms
• Addition-specific compliance documentation
• Alteration-specific compliance documentation
• Mechanical-system forms
• Lighting compliance forms
• Installation documentation
• Field-verification documentation when applicable
• Acceptance-testing documentation for applicable nonresidential systems

The practical question is therefore not simply whether Title 24 applies.

The better question is:

What Title 24 energy documentation is required for this specific project?

Alternative Energy Systems brings more than 30 years of California energy-compliance experience to residential, multifamily, mixed-use, and commercial projects.

Call (626) 365-1518 if you need to determine whether your project requires a full energy analysis, prescriptive compliance forms, a revised report, or another form of Title 24 documentation.

The Short Answer: A Title 24 Energy Report Is Commonly Required When a Project Changes Building Energy Performance

A Title 24 energy report or other applicable compliance documentation is commonly required when construction creates or modifies conditioned space or changes regulated energy-related building systems.

Examples include:

• New homes
• New ADUs
• Garage conversions
• Room additions
• Second-story additions
• Major residential remodels
• Multifamily construction
• Multifamily alterations
• New commercial buildings
• Commercial tenant improvements
• HVAC replacements or major mechanical changes
• Window alterations
• Envelope alterations
• Water-heating changes
• Commercial lighting alterations

The exact documentation depends on what is actually being built or altered.

A new house may require comprehensive whole-building calculations.

A window alteration, HVAC replacement, or small addition may follow a more limited compliance path.

Title 24 Applying to a Project Does Not Always Mean a Full Performance Report Is Required

This is one of the most important distinctions for homeowners, contractors, and designers to understand.

California’s Energy Code contains:

• Mandatory requirements
• Prescriptive compliance requirements
• Performance compliance requirements

A project can be subject to Title 24 while complying through prescriptive forms instead of a full whole-building performance model.

For example, certain residential additions and alterations have dedicated prescriptive compliance forms.

Therefore:

Title 24 applies and a full performance energy report is required are not always the same statement.

AES can review the actual scope before determining which compliance path makes sense.

When Is a Performance-Based Title 24 Report Required?

A performance-based analysis evaluates the building using approved energy-compliance software.

The proposed design is compared with the applicable standard design or energy budget.

Performance modeling is commonly used when:

• A newly constructed building is using the performance approach
• The design does not follow a straightforward prescriptive path
• Energy-efficiency tradeoffs are needed
• The project has extensive glazing or other design conditions that benefit from whole-building analysis
• The project team wants additional design flexibility
• An addition or alteration elects to use an available performance compliance path

For applicable 2025 Energy Code performance calculations, approved compliance software must be used.

For more information about how these calculations work, review Title 24 energy calculations.

When Can Prescriptive Compliance Be Used Instead?

Prescriptive compliance follows specific component and system requirements established by the Energy Code.

Depending on the project, this can avoid the need for a complete whole-building performance model.

Prescriptive documentation can be available for qualifying:

• Residential additions
• Residential alterations
• HVAC alterations
• Envelope alterations
• Other project-specific scopes

The project still needs to satisfy applicable Energy Code requirements.

Using a prescriptive form does not mean the project is exempt from Title 24.

It means compliance is being demonstrated through a different method.

When Is a Title 24 Energy Report Required for New Residential Construction?

New residential construction is subject to the applicable California Energy Code requirements.

A newly constructed home can require analysis involving:

• Building orientation
• Conditioned floor area
• Exterior walls
• Roof and ceiling assemblies
• Floors
• Insulation
• Windows
• Glazed exterior doors
• HVAC systems
• Ductwork
• Ventilation
• Water heating
• Other applicable energy measures

When the project uses the performance compliance approach, the proposed building is modeled using approved compliance software.

The resulting compliance documentation supports the permit set and identifies the energy features that need to remain coordinated with the plans.

When Is a Title 24 Energy Report Required for an ADU?

ADUs commonly require Title 24 energy documentation.

The exact requirements depend on whether the ADU is:

• New and detached
• Attached to an existing residence
• Created through a garage conversion
• Created by converting another existing space

A newly constructed detached ADU may require analysis similar to other new residential construction.

A conversion or attached ADU may need to distinguish between existing construction and new conditioned space.

Energy-related information can include:

• Floor area
• Walls
• Roof assemblies
• Insulation
• Windows
• HVAC
• Ventilation
• Water heating

Visit the ADU Title 24 page for additional information.

When Is a Title 24 Energy Report Required for a Garage Conversion?

A garage conversion commonly triggers energy requirements because space that was previously unconditioned can become conditioned residential space.

The project may need to address:

• Wall insulation
• Ceiling or roof insulation
• Floor conditions
• Windows
• Exterior doors
• HVAC
• Ventilation
• Water heating when applicable

The fact that the garage already exists does not automatically exempt the conversion from Energy Code requirements.

The new use and construction scope matter.

When Is a Title 24 Energy Report Required for a Home Addition?

Residential additions are subject to applicable Energy Code requirements.

Examples include:

• Bedroom additions
• Family-room additions
• Kitchen expansions
• Primary-suite additions
• Second-story additions
• Expanded living areas

An addition can introduce:

• New conditioned floor area
• New walls
• New roof assemblies
• New windows
• New insulation
• New mechanical loads

The project can potentially use either an applicable prescriptive or performance approach, depending on its size and design.

Not every addition automatically requires the same full performance analysis.

Do Small Residential Additions Need a Full Energy Model?

Not necessarily.

California provides prescriptive compliance paths for qualifying residential additions.

For the 2025 Energy Code, there are dedicated residential addition compliance forms for qualifying projects.

The form and registration requirements can also depend on whether the project triggers field verification and diagnostic testing.

This is why the project should be reviewed before assuming either:

• A complete performance model is mandatory
• No energy documentation is required

The correct answer depends on the addition itself.

When Is a Title 24 Energy Report Required for a Remodel?

The word “remodel” covers many different types of work.

A cosmetic interior remodel can be different from an alteration affecting regulated energy components.

Title 24 documentation may become necessary when the project changes:

• Windows
• Exterior doors
• Exterior walls
• Insulation
• Roofing
• HVAC equipment
• Duct systems
• Ventilation
• Water heating
• Commercial lighting

A limited alteration may use specific prescriptive forms rather than a full performance report.

The complete scope must be reviewed first.

When Do Window Replacements Trigger Title 24?

Window alterations can trigger applicable Energy Code requirements.

Window compliance can involve:

• U-factor
• Solar heat gain coefficient
• Window area
• Other applicable fenestration requirements

The exact documentation depends on whether the windows are being changed as part of:

• A new building
• An addition
• A remodel
• A stand-alone alteration

A complete whole-building report may not always be required for limited replacement work, but applicable Title 24 requirements can still apply.

When Do Insulation Changes Trigger Title 24?

Alterations to regulated envelope assemblies can fall under Energy Code requirements.

This can involve changes to:

• Walls
• Roofs
• Ceilings
• Attics
• Floors

Whether a separate calculation or prescriptive compliance form is needed depends on the project.

The insulation information should also remain coordinated with the construction drawings.

When Does Roofing Trigger Title 24?

Roofing alterations can have applicable Energy Code requirements depending on:

• Building type
• Roof slope
• Roofing characteristics
• Climate zone
• Project scope

Not every roofing project requires a complete building energy model.

However, applicable roof requirements should still be reviewed rather than assuming that replacement roofing is outside Title 24.

When Is Title 24 Documentation Required for HVAC Replacement?

HVAC replacements and other mechanical alterations can trigger Energy Code requirements.

Applicable documentation can address:

• Equipment type
• Equipment efficiency
• Duct systems
• Controls
• Airflow
• Field verification when required

For single-family buildings, the California Energy Commission provides alteration-specific forms for space-conditioning systems.

A mechanical replacement therefore may need energy-compliance documentation even when no architectural addition is being built.

When Do Duct Changes Trigger Additional Requirements?

Duct additions or alterations can affect energy compliance.

The project may involve requirements related to:

• Duct sealing
• Duct insulation
• Duct location
• Airflow
• Field verification

Some HVAC additions and alterations require separate field verification and diagnostic testing.

When required, those measures are identified in the applicable compliance documentation.

When Is a Title 24 Energy Report Required for Multifamily Buildings?

Applicable multifamily projects are subject to the California Energy Code.

This can include:

• New apartment buildings
• New multifamily housing
• Multifamily additions
• Apartment alterations
• Common-area improvements
• Mechanical changes
• Water-heating changes
• Lighting alterations

Multifamily compliance has its own requirements and forms.

The project should not automatically use a single-family report or a commercial report simply because some building features appear similar.

When Is a Title 24 Energy Report Required for New Commercial Construction?

New nonresidential construction is subject to applicable Energy Code requirements.

Depending on the building, energy compliance can involve:

• Building envelope
• Fenestration
• Mechanical systems
• Ventilation
• Service water heating
• Interior lighting
• Exterior lighting
• Lighting controls
• Other regulated systems

A performance-based analysis may be used when permitted by the applicable compliance method.

Prescriptive requirements may also be available.

For commercial services, review Title 24 compliance services.

When Is Title 24 Required for a Commercial Tenant Improvement?

A tenant improvement can trigger Energy Code requirements even though the overall building already exists.

Examples include:

• Office remodels
• Retail build-outs
• Restaurant improvements
• Medical office improvements
• Warehouse office alterations
• Service-business tenant spaces

The work can affect:

• Lighting
• Lighting controls
• HVAC
• Ventilation
• Water heating
• Storefront glazing
• Other regulated systems

The required energy package should correspond to the actual tenant scope rather than simply reusing the shell building’s previous documentation.

When Is Title 24 Required for Commercial Lighting?

Commercial lighting alterations can trigger nonresidential Energy Code requirements.

Depending on the scope, documentation can involve:

• Lighting power
• Fixture wattage
• Fixture quantities
• Occupancy controls
• Automatic shutoff controls
• Daylighting controls
• Exterior lighting

Certain systems may also require acceptance testing.

A complete whole-building model is not always required for a lighting-only alteration, but applicable lighting compliance documentation can still be necessary.

When Is Title 24 Required for Commercial HVAC Work?

Commercial mechanical alterations can trigger requirements involving:

• Equipment efficiency
• System type
• Ventilation
• Controls
• Economizers when applicable
• Other mechanical measures

The applicable compliance forms depend on the system and project scope.

When Is a Title 24 Report Not Required?

Not every construction activity requires a full Title 24 energy report.

Examples can include:

• Some true repair work
• Some cosmetic improvements
• Some scopes that do not alter regulated energy components
• Projects using limited prescriptive compliance documentation rather than a whole-building performance report

However, this section requires an important caution:

No full energy report required does not necessarily mean no Energy Code requirements apply.

For example, a limited alteration can still have mandatory or prescriptive requirements.

Likewise, replacing a regulated component may be considered an alteration rather than a simple repair.

The actual construction scope should be reviewed before assuming an exemption.

Is a Repair the Same as an Alteration?

No.

The Energy Code distinguishes between repair work and alterations.

A true repair can be treated differently from a project that replaces or changes a regulated building component.

The name written on a contractor’s estimate does not determine Energy Code treatment by itself.

The actual work matters.

For example, replacing:

• Windows
• HVAC equipment
• Duct systems
• Water-heating equipment
• Roofing

can have applicable alteration requirements even when the owner considers the work a repair or replacement.

Does a Building Permit Automatically Mean a Full Title 24 Report Is Required?

No.

A permit and a full performance energy report are not the same thing.

A permit project can require:

• Prescriptive energy forms
• Mechanical compliance documentation
• Lighting forms
• Installation forms
• Verification forms

without requiring the same type of whole-building performance model used for a new house.

The correct form of compliance depends on the project.

Does No Building Permit Automatically Mean Title 24 Does Not Apply?

No.

Permit requirements and Energy Code requirements are related but not identical.

Whether the Energy Code applies depends on the actual work and applicable regulations.

Questions about whether a permit is required should be confirmed with the authority having jurisdiction.

AES can evaluate the energy-compliance implications of the project scope.

What Is the Current Title 24 Energy Code?

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

The current standards apply to residential and nonresidential:

• Newly constructed buildings
• Additions
• Alterations

For official current information, review the California Energy Commission 2025 Building Energy Efficiency Standards.

The Permit Application Date Can Matter

California updates the Energy Code on a three-year cycle.

The code edition applied to a project is tied to the applicable permit circumstances.

For new permit applications filed on or after January 1, 2026, the 2025 Energy Code is the current statewide edition.

A project that began under an earlier code cycle can have different circumstances.

If the project crosses a code-cycle transition, confirm the applicable requirements with the building department before assuming which forms or calculations should be used.

When Should a Title 24 Report Be Prepared?

Ideally, energy compliance should be reviewed before the construction documents are considered final.

Early preparation allows AES to identify:

• Missing window information
• Missing insulation values
• Incomplete roof assemblies
• Undecided HVAC equipment
• Duct-location issues
• Ventilation questions
• Water-heating changes
• Incomplete commercial lighting information

Addressing these issues before plan check can reduce avoidable revisions.

Can the Report Be Started Before the Plans Are Finished?

Preliminary review can often begin with available plans.

However, enough project information must eventually be available to complete the analysis accurately.

Final documentation may require:

• Confirmed floor area
• Final window sizes
• Window performance
• Final insulation assemblies
• HVAC equipment information
• Water-heating information
• Commercial lighting information when applicable

The report should not be finalized around assumptions that no longer match the actual design.

When Does an Existing Title 24 Report Need to Be Revised?

A previously prepared report may need revision when the project changes:

• Conditioned floor area
• Building geometry
• Windows
• Exterior doors
• Insulation
• Roof construction
• HVAC equipment
• Duct layout
• Ventilation
• Water heating
• Lighting
• Controls

Send revised plans to AES before assuming the previous calculations remain applicable.

What Happens if the Building Department Requests a Title 24 Report?

If a plan reviewer requests energy documentation, send AES:

• The complete correction notice
• The current architectural plans
• The project description
• Existing Title 24 documentation
• Current mechanical information
• Current window specifications
• Current water-heating specifications
• Commercial lighting information when applicable

AES can review whether the project requires:

• A performance calculation
• Prescriptive compliance forms
• A mechanical form
• A lighting form
• A revision to an existing report
• Additional plan coordination

Why the Report Must Match the Plans

The energy report and construction drawings serve different purposes, but they should describe the same project.

Potential conflicts include:

• Different floor area
• Different window sizes
• Different window performance
• Different insulation
• Different HVAC equipment
• Different water-heating equipment
• Different lighting design

A technically correct report based on outdated plans can still create permit problems.

For additional background, review Title 24 energy compliance.

What Documents Should You Send AES?

Helpful information can include:

• Floor plans
• Exterior elevations
• Building sections
• Roof plans
• Window schedules
• Window specifications
• Insulation details
• HVAC specifications
• Duct-location information
• Ventilation information
• Water-heating information
• Commercial lighting plans
• Commercial lighting-control information
• Existing energy reports
• Building-department corrections

Not every project requires every item.

AES can review the available plans and identify what is still needed.

Before sending documents, review what AES will need from you.

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides professional Title 24 calculations, compliance documentation, 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 alterations
• Multifamily projects
• Mixed-use buildings
• Commercial construction
• Office tenant improvements
• Retail projects
• Restaurant projects
• Warehouse alterations
• HVAC projects
• Commercial lighting projects
• Energy-related plan-check corrections

AES reviews the actual project scope before determining what level of Title 24 documentation is appropriate.

Learn more through the About Us page or review company background on the clients page.

Find Out Whether Your Project Requires a Title 24 Energy Report

Call (626) 365-1518 | Alternative Energy Systems

Understanding When Is a Title 24 Energy Report Required begins with identifying:

• The building type
• The construction scope
• The components and systems being changed
• The applicable Energy Code cycle
• The compliance method

New buildings generally require substantial energy-compliance documentation.

ADUs, additions, garage conversions, remodels, multifamily alterations, commercial tenant improvements, HVAC changes, and lighting projects can also trigger Title 24 requirements.

However, not every project needs the same full performance report.

Alternative Energy Systems can help determine whether the project needs:

• Performance calculations
• Prescriptive compliance documentation
• Mechanical energy forms
• Commercial lighting documentation
• A revision to an existing report
• Other project-specific energy documentation

Call (626) 365-1518 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: When Is a Title 24 Energy Report Required?

When Is a Title 24 Energy Report Required?

Title 24 energy documentation is generally required when an applicable California project involves new construction, an addition, an alteration, or regulated energy-related building systems. The exact form of documentation depends on the project and compliance method.

Does every project require a full performance report?

No. Some additions, alterations, mechanical projects, and other scopes can use applicable prescriptive or system-specific compliance forms.

When is a performance report required?

Performance analysis is used when the project follows the performance compliance method. Newly constructed buildings using this approach must use California Energy Commission-approved compliance software.

When can prescriptive compliance be used?

Prescriptive compliance can be available when the project satisfies the applicable component and system requirements established by the Energy Code.

Does a new house need Title 24 documentation?

Yes. Newly constructed residential buildings are subject to applicable Energy Code requirements and require the appropriate compliance documentation.

Does a new ADU need a Title 24 report?

A new ADU generally requires applicable energy-compliance documentation. The exact analysis depends on whether it is detached, attached, or a conversion.

Does a garage conversion require Title 24?

It commonly does because unconditioned space is being converted into conditioned residential space.

Does a room addition require Title 24?

Applicable additions are subject to Energy Code requirements. The project may use a prescriptive or performance compliance path depending on its characteristics.

Does a small addition need a full energy model?

Not necessarily. Qualifying additions may use applicable prescriptive compliance forms.

Does a remodel require Title 24?

It can. Alterations affecting regulated components such as windows, insulation, HVAC, ducts, roofing, water heating, or commercial lighting can trigger requirements.

Do replacement windows require Title 24?

Window alterations can be subject to applicable fenestration requirements even when a full whole-building energy model is not required.

Does replacing an HVAC system trigger Title 24?

It can. Space-conditioning alterations can require equipment, duct, control, and verification documentation.

Does duct replacement require Title 24?

Applicable duct alterations can trigger sealing, insulation, airflow, or verification requirements.

Does replacing a water heater require Title 24?

Water-heating alterations can be subject to applicable Energy Code requirements depending on building type and project scope.

Does roofing require Title 24?

Roof alterations can be subject to applicable roof and energy-efficiency requirements depending on the project.

Do commercial tenant improvements require Title 24?

They can. Lighting, HVAC, ventilation, water heating, glazing, and other altered systems can trigger nonresidential Energy Code requirements.

Do commercial lighting projects require Title 24?

Applicable lighting alterations can require lighting-power, control, and other compliance documentation even without a full building energy model.

Do commercial HVAC replacements require Title 24?

Applicable mechanical alterations can trigger equipment-efficiency, ventilation, control, and other Energy Code requirements.

Do multifamily projects require Title 24 documentation?

Yes. Applicable new multifamily construction, additions, and alterations are subject to multifamily Energy Code requirements.

Are repairs exempt from Title 24?

Some true repair work can be treated differently from an alteration, but replacement of regulated components can trigger applicable requirements. The actual scope should be reviewed.

Does every building permit require a full Title 24 report?

No. Some permits require limited prescriptive or system-specific energy forms instead.

If I do not need a full report, does that mean Title 24 does not apply?

No. Energy Code requirements can still apply even when compliance is demonstrated through prescriptive or limited forms.

Does no permit mean Title 24 does not apply?

Not automatically. Permit requirements and Energy Code applicability are related but separate questions.

What Energy Code applies now?

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

When should I order the report?

Energy review is best started before the construction plans are considered final so missing information and design conflicts can be addressed before plan check.

Can the report be prepared before plans are complete?

Preliminary review can begin earlier, but final documentation requires enough project information to complete the analysis accurately.

When does an existing report need revision?

A revision may be needed when floor area, windows, insulation, roofing, HVAC, ducts, ventilation, water heating, lighting, or other analyzed features change.

What if the building department asks for a Title 24 report?

Send AES the complete correction notice and current plans so the required compliance path and documentation can be identified.

How do I know whether my project needs a full report or only forms?

Call Alternative Energy Systems at (626) 365-1518 and provide the project scope and current plans for review.

Is Title 24 the Same as CALGreen?

Call (626) 365-1518 | Alternative Energy Systems

Is Title 24 the Same as CALGreen is a common question because the terms are frequently used together during California building permit review.

The short answer is:

No, the Title 24 Energy Code and CALGreen are not the same code. However, CALGreen is one part of the larger California Building Standards Code known as Title 24.

More specifically:

• California Energy Code: Title 24, Part 6
• CALGreen: Title 24, Part 11
• Title 24: The broader California Building Standards Code containing multiple parts

This distinction matters because a project can comply with its Title 24 energy calculations and still have separate CALGreen requirements that must be addressed elsewhere in the plans and permit documents.

The Energy Code focuses primarily on building energy efficiency.

CALGreen addresses a broader group of green-building measures that can include water efficiency, construction waste, material-related requirements, indoor environmental quality, electric-vehicle infrastructure, and other sustainable building practices.

For applicable permit applications filed on or after January 1, 2026, California is using the 2025 editions of both the Energy Code and CALGreen.

Alternative Energy Systems focuses on California energy-compliance calculations and documentation associated with the Energy Code.

Call (626) 365-1518 if you need Title 24 energy calculations, a compliance report, revisions, or assistance coordinating the energy documentation with your plans.

The Important Distinction: Title 24 Is the Entire Building Standards Code

A large part of the confusion comes from the way people use the phrase “Title 24.”

In everyday construction conversations, someone may say:

“I need Title 24.”

Usually, that person means they need an energy calculation or Energy Code compliance report.

Technically, however, Title 24 is much broader.

California’s Building Standards Code is divided into multiple parts covering subjects such as:

• Administrative requirements
• Building construction
• Residential construction
• Electrical systems
• Mechanical systems
• Plumbing systems
• Energy efficiency
• Fire requirements
• Existing buildings
• Green building standards

The Energy Code is only one part of that larger system.

CALGreen is another.

What Part of Title 24 Is the Energy Code?

California’s Building Energy Efficiency Standards are primarily contained in:

Title 24, Part 6.

This is the portion commonly associated with:

• Title 24 energy calculations
• Energy compliance reports
• Building-envelope performance
• Windows
• Insulation
• HVAC systems
• Duct systems
• Ventilation
• Water heating
• Lighting
• Lighting controls
• Solar and battery requirements when applicable
• Energy-related verification requirements

When Alternative Energy Systems prepares Title 24 calculations, the work is primarily associated with Energy Code compliance rather than every requirement contained in the broader California Building Standards Code.

What Part of Title 24 Is CALGreen?

CALGreen is formally known as the California Green Building Standards Code.

It is:

Title 24, Part 11.

CALGreen contains mandatory green-building requirements for applicable projects as well as additional voluntary measures.

Depending on the project and jurisdiction, CALGreen can address subjects involving:

• Planning and design
• Water efficiency
• Material conservation
• Resource efficiency
• Environmental quality
• Construction waste
• Pollutant control
• Electric-vehicle infrastructure
• Other green-building measures

These subjects overlap with the broad goal of improving building performance, but they are not identical to the energy calculations performed under Part 6.

What Is the Main Difference Between the Energy Code and CALGreen?

The easiest way to understand the difference is by looking at their primary focus.

Title 24, Part 6: Energy Performance

The Energy Code focuses on reducing inefficient or unnecessary building energy consumption.

It can regulate or evaluate:

• Building envelope
• Insulation
• Fenestration
• Roof characteristics
• Heating
• Cooling
• Ducts
• Ventilation
• Water heating
• Lighting
• Controls
• Other energy-related systems

Title 24, Part 11: Green Building

CALGreen has a broader sustainability focus.

Its mandatory provisions can address topics beyond direct energy calculations, including:

• Water conservation
• Material conservation
• Construction waste management
• Indoor environmental quality
• Pollutant control
• Site-related measures
• Electric-vehicle infrastructure
• Other green-building practices

A project may therefore need to demonstrate compliance with both codes.

Why Are the Two Codes Often Confused?

There are several reasons.

First, both are contained within Title 24.

Second, both can affect the same building project.

Third, both are updated through California’s building-code cycle.

Fourth, some subjects can appear related.

For example:

• Energy-efficient buildings can also be considered greener buildings
• Ventilation can affect both energy performance and indoor environmental quality
• Electric vehicle infrastructure interacts with building electrical systems
• Solar and energy systems relate to broader sustainability goals

But overlap in purpose does not mean the two codes are interchangeable.

Does a Title 24 Energy Report Cover CALGreen?

Not automatically.

A Title 24 energy report prepared under Part 6 documents the applicable energy-related characteristics of the project.

That can include:

• Energy calculations
• Building-envelope measures
• Window performance
• Insulation
• Mechanical systems
• Ventilation information
• Water-heating information
• Lighting and controls when applicable

It should not be assumed to satisfy every CALGreen requirement.

CALGreen documentation may require additional information elsewhere in the plans, specifications, forms, or construction documents.

A CALGreen Checklist Is Not the Same as a Title 24 Energy Calculation

A CALGreen checklist can identify applicable green-building requirements.

That is different from an energy model or Title 24 calculation.

Energy compliance may require evaluation of variables such as:

• Climate zone
• Building size
• Orientation
• Conditioned floor area
• Window area
• Window performance
• Insulation
• HVAC efficiency
• Duct conditions
• Water heating

Checking CALGreen items does not replace that calculation.

Likewise, completing an energy model does not automatically complete the project’s CALGreen obligations.

Do Both Codes Apply to Residential Construction?

They can.

Applicable residential projects may have Energy Code requirements under Part 6 and separate CALGreen requirements under Part 11.

A new home, for example, may need energy documentation addressing:

• Walls
• Roofs
• Insulation
• Windows
• HVAC
• Ventilation
• Water heating

The same project can also have separate CALGreen requirements involving applicable green-building measures.

The project team should therefore review both parts rather than assuming one substitutes for the other.

Do Both Codes Apply to ADUs?

Depending on the ADU configuration and project scope, both Energy Code and CALGreen requirements can be relevant.

An ADU may involve energy-related analysis of:

• Conditioned floor area
• Wall assemblies
• Roof assemblies
• Windows
• Insulation
• HVAC
• Ventilation
• Water heating

Separate green-building requirements may also apply.

For more information about the energy side of these projects, review ADU Title 24.

Do Both Codes Apply to Residential Additions?

They can, depending on project size, scope, and applicable code provisions.

Energy Code requirements can be triggered when an addition creates new conditioned floor area and new building-envelope components.

CALGreen applicability should be evaluated separately.

Do not assume that because an addition requires an energy report it automatically requires every CALGreen measure, or vice versa.

Each code contains its own scope and application provisions.

Do Both Codes Apply to Remodels?

Potentially.

Existing-building work can trigger requirements under one or both codes depending on what is being altered.

A project involving:

• Windows
• HVAC equipment
• Water heating
• Lighting
• Plumbing fixtures
• Interior finish materials

may interact with different portions of California’s building standards.

The exact scope should be reviewed rather than relying on the general word “remodel.”

Do Both Codes Apply to Multifamily Buildings?

Multifamily projects can have requirements under both Part 6 and Part 11.

Energy compliance may involve:

• Building envelope
• Dwelling-unit systems
• Central systems
• Ventilation
• Water heating
• Lighting
• Solar and battery requirements when applicable

CALGreen can add separate requirements involving other green-building topics.

Multifamily projects should therefore be coordinated across the complete permit set rather than treating energy compliance as the only sustainability-related review.

Do Both Codes Apply to Commercial Buildings?

Yes, applicable nonresidential construction can involve both Energy Code and CALGreen requirements.

Part 6 may address:

• Building envelope
• Mechanical systems
• Ventilation
• Service water heating
• Interior lighting
• Exterior lighting
• Lighting controls
• Solar and battery provisions when applicable

Part 11 can address other green-building provisions.

A commercial project may therefore require coordination among:

• Architect
• Energy consultant
• Mechanical engineer
• Electrical designer
• Plumbing designer
• General contractor
• Other project professionals

For energy-related commercial assistance, review Title 24 compliance services.

What Does CALGreen Cover That the Energy Code Does Not Primarily Address?

CALGreen extends beyond building energy calculations.

Depending on building type and scope, CALGreen can include requirements involving areas such as:

• Water-efficient fixtures
• Indoor water use
• Outdoor water considerations
• Construction waste management
• Material conservation
• Low-emitting materials
• Indoor environmental quality
• Pollutant control
• Electric-vehicle charging infrastructure
• Other sustainable construction practices

These measures demonstrate why CALGreen should not be reduced to an energy-efficiency checklist.

What Does the Energy Code Cover That Is Different From CALGreen?

Part 6 focuses much more directly on quantitative building energy performance.

Energy analysis can involve:

• Climate zone
• Energy budgets
• Performance modeling
• Prescriptive energy requirements
• Wall and roof performance
• Window U-factor
• Solar heat gain coefficient
• HVAC efficiency
• Duct requirements
• Water-heating efficiency
• Lighting power
• Lighting controls

These technical calculations are central to Part 6 compliance.

Is Ventilation a Title 24 or CALGreen Requirement?

This question illustrates why the two codes can appear to overlap.

Ventilation and indoor environmental quality can interact with requirements found in different parts of California’s building standards.

Part 6 contains Energy Code ventilation requirements.

CALGreen also includes indoor environmental quality provisions.

The correct response is not to choose one code and ignore the other.

The design team should identify which specific requirement applies under each applicable code section.

Is Water Efficiency Part of Title 24 Energy Calculations?

Energy use associated with water heating is relevant to Part 6.

However, broader water-conservation requirements can be addressed elsewhere, including CALGreen and other applicable California codes.

For example:

• Water-heater efficiency can affect Energy Code compliance
• Water-efficient plumbing fixtures can involve different code requirements

These are related concepts but not the same compliance calculation.

Are Electric Vehicle Requirements Part of the Energy Report?

Do not assume every electric-vehicle requirement is included in an ordinary Title 24 energy report.

CALGreen contains important electric-vehicle infrastructure requirements for applicable projects.

Other electrical requirements can also apply.

The architect and electrical design team should coordinate these requirements within the complete permit package.

An energy consultant’s Part 6 report should not automatically be treated as the project’s complete EV-compliance documentation.

Are Solar Requirements Part of CALGreen or the Energy Code?

Applicable solar photovoltaic requirements can be contained within California’s Energy Code.

The current Energy Code includes solar-related provisions for qualifying residential, multifamily, and nonresidential projects.

CALGreen can contain related sustainability provisions, including voluntary energy-efficiency measures.

The correct requirement should therefore be identified by the specific code section rather than assuming every sustainability-related feature belongs exclusively to CALGreen.

Are Battery Requirements Part of CALGreen?

The current Energy Code contains battery-energy-storage requirements or readiness provisions for certain qualifying projects.

CALGreen may also contain related provisions within its broader green-building framework.

The applicability can vary by building type and project scope.

The project team should review both the Energy Code and CALGreen rather than assigning every battery-related issue to only one code without checking the applicable section.

What Are CALGreen Tier 1 and Tier 2?

CALGreen includes additional voluntary measures commonly organized into Tier 1 and Tier 2.

These go beyond the statewide mandatory minimum provisions.

A local jurisdiction can adopt qualifying voluntary measures and make them mandatory locally through the applicable legal process.

This means a project can encounter:

• Statewide mandatory CALGreen requirements
• Additional locally adopted green-building requirements

Do not assume that every California jurisdiction uses the same voluntary tier requirements.

Local project requirements should be checked with the applicable authority having jurisdiction.

Are All CALGreen Requirements Voluntary?

No.

This is another common misunderstanding.

CALGreen contains mandatory provisions.

It also contains additional voluntary measures.

The California Building Standards Commission describes CALGreen as California’s mandatory green-building standards code.

Tier 1 and Tier 2 contain additional voluntary provisions that can be adopted by local jurisdictions.

Therefore:

CALGreen itself is not simply an optional green-building program.

Are All CALGreen Requirements the Same Statewide?

California establishes statewide mandatory provisions, but local jurisdictions can adopt qualifying additional green-building requirements through applicable procedures.

This means the exact requirements can differ when a city or county has adopted additional measures.

The building department should be consulted when local CALGreen requirements are unclear.

Does the California Energy Commission Control CALGreen?

Not by itself.

The California Building Standards Commission has significant responsibility for CALGreen and can propose green-building standards for applicable nonresidential occupancies where another state agency does not have authority.

Other California agencies also have authority over particular building occupancies.

The California Energy Commission contributes energy-related provisions, including voluntary energy-efficiency measures contained within CALGreen.

This differs from Part 6, where the California Energy Commission is the primary state agency responsible for developing and implementing the Energy Code.

Who Enforces CALGreen?

For most ordinary projects, the applicable authority having jurisdiction—often the local city or county building department—reviews and enforces applicable CALGreen requirements as part of the permit process.

The same building department may therefore review:

• Energy Code documentation
• CALGreen requirements
• Building-code requirements
• Mechanical requirements
• Electrical requirements
• Plumbing requirements

This can make the codes appear to be one document from the applicant’s perspective even though they contain separate requirements.

Who Enforces the Energy Code?

For ordinary projects, the authority having jurisdiction also generally reviews and enforces Energy Code compliance through:

• Plan review
• Correction comments
• Permit approval
• Construction inspections
• Review of applicable compliance documentation

The fact that the same building department may enforce both Part 6 and Part 11 does not make those codes identical.

Do Title 24 and CALGreen Use the Same Forms?

Not necessarily.

Energy Code compliance can use project-specific forms documenting:

• Design compliance
• Installation
• Verification
• Acceptance testing when applicable

CALGreen documentation can use different checklists, plan notes, forms, specifications, and supporting documents.

One set of forms should not automatically be substituted for the other.

Why Do Both Codes Need to Match the Plans?

Both codes ultimately apply to the actual building being permitted and constructed.

The plans may need to communicate requirements involving:

• Insulation
• Windows
• Mechanical systems
• Ventilation
• Water heating
• Lighting
• Water conservation
• Waste management
• Low-emitting materials
• Electric-vehicle infrastructure

If separate compliance documents contradict the construction drawings, building-department corrections can result.

Can a Project Pass Title 24 Energy Compliance but Fail CALGreen Review?

Yes.

A project may have a correct Part 6 energy calculation while still having missing or incorrect Part 11 information.

For example, an energy report can correctly demonstrate:

• Window performance
• Insulation
• HVAC efficiency
• Water-heating energy performance

while the permit set could still be missing a separate CALGreen requirement.

The reverse is also possible.

A complete CALGreen checklist does not correct an inaccurate energy model.

Can a Project Satisfy CALGreen but Fail Energy Compliance?

Yes.

CALGreen compliance does not replace Energy Code compliance.

A project may satisfy applicable requirements involving waste management, materials, or water efficiency while still having an energy issue involving:

• Windows
• Insulation
• HVAC
• Ducts
• Water-heating efficiency
• Lighting power
• Energy-model results

Both applicable code paths need to be addressed.

Do the Current 2025 Codes Use the Same Effective Date?

Yes.

The current 2025 California Energy Code and 2025 CALGreen Code became effective January 1, 2026.

For applicable permit applications under the current cycle, the project team should use the correct 2025 documentation rather than forms from an earlier edition.

Are Both Codes Updated Every Three Years?

The major editions of California’s Building Standards Code follow a three-year cycle.

This keeps Energy Code and CALGreen updates aligned with the broader California building-code cycle.

Current editions include:

• 2025 Energy Code – Title 24, Part 6
• 2025 CALGreen – Title 24, Part 11

The next major code cycle will continue that triennial process.

What Happens if You Use an Old CALGreen Checklist With a New Title 24 Report?

Using documents from different code cycles can create permit-review problems.

A current project should be checked for the applicable:

• Energy Code edition
• CALGreen edition
• Building Code edition
• Local amendments
• Required forms

Do not assume that a checklist or report from an older project remains suitable simply because the new project looks similar.

How Should Architects Coordinate Part 6 and Part 11?

Architects and building designers should treat energy and CALGreen requirements as separate but coordinated parts of the permit set.

The architect may need to coordinate with:

• Energy consultant
• Mechanical engineer
• Electrical designer
• Plumbing designer
• Contractor
• Owner

This helps ensure the final drawings communicate requirements from all applicable codes rather than allowing one compliance package to contradict another.

What Should Contractors Know About the Difference?

Contractors should not assume that following the energy report automatically satisfies every green-building requirement.

During construction they may encounter requirements relating to:

• Energy-efficient products
• Insulation
• HVAC
• Ventilation
• Water conservation
• Construction waste
• Material selection
• Pollutant control
• Other project-specific measures

The approved plans and specifications should identify the requirements applicable to the actual construction.

What Should Homeowners Know?

For homeowners, the main point is simple:

A Title 24 energy report is not the complete California building-code package.

Your project may need several different types of compliance documentation.

For example, an ADU could involve:

• Architectural plans
• Structural documents
• Title 24 energy calculations
• CALGreen requirements
• Mechanical information
• Electrical information
• Plumbing information

Each document supports a different part of the permit review.

What if the Building Department Requests Both Title 24 and CALGreen Corrections?

Separate the comments by subject.

An energy-related correction may involve AES when it concerns:

• Energy calculations
• Windows
• Insulation
• HVAC information
• Water heating
• Energy forms

A CALGreen correction may need to be addressed by the architect, designer, contractor, or another project professional depending on the issue.

Send AES the complete correction notice rather than one isolated comment.

AES can identify which comments fall within the energy-compliance scope and which should be coordinated with another professional.

What Should You Send AES?

For Title 24 energy-compliance services, useful project information can include:

• Floor plans
• Exterior elevations
• Building sections
• Roof plans
• Window schedules
• Insulation details
• HVAC specifications
• Duct information
• Ventilation information
• Water-heating specifications
• Commercial lighting plans when applicable
• Building-department correction comments

Before submitting files, 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 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 buildings
• Mixed-use projects
• Commercial buildings
• Office tenant improvements
• Retail projects
• Restaurant projects
• Warehouse alterations
• HVAC projects
• Commercial lighting projects
• Energy-related plan-check corrections

AES focuses on the energy-compliance portion of the permit package and helps coordinate those requirements with the actual plans.

Learn more through the About Us page or review company background on the clients page.

Need Help Separating Title 24 Energy Requirements From CALGreen?

Call (626) 365-1518 | Alternative Energy Systems

Understanding Is Title 24 the Same as CALGreen becomes easier once the code structure is clear.

CALGreen is part of Title 24, but it is not the same as the Energy Code.

The practical distinction is:

• Title 24, Part 6: California Energy Code
• Title 24, Part 11: CALGreen

Part 6 focuses primarily on energy performance.

Part 11 addresses a broader range of green-building requirements.

A project can therefore need both.

Alternative Energy Systems can help with the Title 24 energy-compliance portion of your project, including:

• Energy calculations
• Compliance reports
• Energy forms
• Plan coordination
• Report revisions
• Energy-related plan-check corrections

Call (626) 365-1518 or begin through the contact page.

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

For official information about the Energy Code, review the California Energy Commission 2025 Building Energy Efficiency Standards.

For official information about CALGreen, review the California Building Standards Commission CALGreen resources.

Frequently Asked Questions: Is Title 24 the Same as CALGreen?

Is Title 24 the Same as CALGreen?

No. CALGreen is Part 11 of the broader California Building Standards Code known as Title 24. The California Energy Code is Part 6.

Is CALGreen part of Title 24?

Yes. CALGreen is formally the California Green Building Standards Code, Title 24, Part 11.

What part of Title 24 is the Energy Code?

California’s Building Energy Efficiency Standards are primarily contained in Title 24, Part 6.

What part of Title 24 is CALGreen?

CALGreen is Title 24, Part 11.

Does a Title 24 energy report satisfy CALGreen?

Not automatically. A Part 6 energy report addresses energy compliance and should not be assumed to satisfy every Part 11 requirement.

Does a CALGreen checklist replace a Title 24 report?

No. CALGreen documentation does not replace applicable Part 6 energy calculations or compliance forms.

Can a project require both?

Yes. Many California permit projects can have both Energy Code and CALGreen requirements.

Is CALGreen mandatory?

Yes. CALGreen contains mandatory green-building requirements for applicable projects as well as additional voluntary measures.

What are CALGreen Tier 1 and Tier 2?

Tier 1 and Tier 2 contain additional voluntary green-building measures beyond statewide mandatory minimums. Local jurisdictions can adopt qualifying measures and make them mandatory locally.

Is Title 24 only about energy?

No. Title 24 is California’s broader Building Standards Code. Energy efficiency is primarily Part 6.

Is CALGreen only about energy?

No. CALGreen addresses broader green-building topics including water efficiency, materials, construction waste, indoor environmental quality, and other sustainability measures.

Does CALGreen regulate water efficiency?

Yes. Applicable CALGreen provisions include water-efficiency requirements.

Does the Energy Code regulate water heating?

Yes. Part 6 regulates applicable energy-related characteristics of water-heating systems.

Are water efficiency and water-heating efficiency the same requirement?

No. They can relate to one another but address different aspects of building performance.

Does CALGreen cover construction waste?

Yes. Applicable CALGreen provisions include material conservation and construction waste requirements.

Does the Energy Code cover construction waste?

Construction waste is not the primary focus of Part 6 energy calculations.

Does CALGreen include electric-vehicle requirements?

Yes. CALGreen contains electric-vehicle infrastructure requirements for applicable projects.

Does Title 24 Part 6 include solar requirements?

Yes. The Energy Code contains solar-related requirements for qualifying projects.

Does Part 6 include battery requirements?

The current Energy Code includes battery-storage or battery-ready provisions for certain qualifying projects.

Can energy and CALGreen requirements overlap?

They can address related building-performance goals, but the requirements remain contained in separate parts of Title 24 and should be reviewed independently.

Who develops the Energy Code?

The California Energy Commission is the primary state agency responsible for California’s Building Energy Efficiency Standards.

Who administers CALGreen?

The California Building Standards Commission and other authorized state agencies have roles in developing and administering CALGreen requirements for applicable occupancies.

Who enforces the Energy Code and CALGreen?

For most ordinary construction projects, the applicable city or county building department reviews and enforces the requirements during permitting and inspection.

What CALGreen code is currently in effect?

The 2025 California Green Building Standards Code became effective January 1, 2026.

What Energy Code is currently in effect?

The 2025 California Building Energy Efficiency Standards became effective January 1, 2026.

Can my city have stricter CALGreen requirements?

A local jurisdiction can adopt qualifying additional green-building measures through the applicable California procedures.

Can AES prepare my Title 24 energy calculations?

Yes. Alternative Energy Systems provides energy-compliance calculations, reports, revisions, and related plan-check support for applicable California projects.

Does AES handle every CALGreen requirement?

AES focuses on energy-compliance services. CALGreen items outside that energy scope may need to be addressed by the architect, designer, contractor, or another appropriate project professional.

How do I get started?

Call Alternative Energy Systems at (626) 365-1518 and provide the current plans and project information for review.

Who Enforces Title 24?

Call (626) 365-1518 | Alternative Energy Systems

Who Enforces Title 24 depends on the building, jurisdiction, and part of California’s building standards involved. For most residential and commercial construction projects, the authority having jurisdiction—usually the city or county building department—reviews and enforces the applicable Title 24 requirements.

For California’s Building Energy Efficiency Standards, commonly called the Energy Code or Title 24, Part 6, the California Energy Commission develops and administers the statewide standards but does not ordinarily perform the local building permit review or construction inspection.

Instead, enforcement generally works through several stages:

1. The state establishes the applicable Energy Code requirements
2. The project team prepares plans and compliance documentation
3. The local building department reviews the permit application
4. Plan examiners compare the Title 24 documentation with the construction plans
5. Corrections are issued when information is missing or inconsistent
6. The permit is issued after applicable requirements are satisfied
7. Contractors install the required materials and systems
8. Applicable field verification or acceptance testing is completed
9. Building inspectors review the construction during required inspections
10. Final documentation and inspections are completed before project closeout

This distinction is important because a Title 24 consultant does not issue the permit, and the California Energy Commission does not normally arrive at an ordinary house or commercial tenant improvement to inspect construction.

Alternative Energy Systems prepares project-specific energy calculations and compliance documentation that can be reviewed by the appropriate enforcement agency.

Call (626) 365-1518 if you need a Title 24 report prepared, revised, or coordinated with building-department correction comments.

The Short Answer: Your Local Building Department Usually Enforces Title 24

For most ordinary California construction projects, enforcement occurs through the city or county that has jurisdiction over the property.

The local building department may be responsible for:

• Accepting the permit application
• Reviewing construction plans
• Reviewing applicable energy-compliance forms
• Checking required project information
• Issuing plan-check corrections
• Approving revised documents
• Issuing the building permit
• Performing construction inspections
• Reviewing applicable installation and verification documentation
• Completing final inspection or permit closeout procedures

The department with enforcement authority is often referred to as the authority having jurisdiction, or AHJ.

For many projects, the AHJ is simply the local city building department.

In an unincorporated area, it may be the county.

Certain specialized buildings can have another state or public agency serving as the enforcement authority.

What Is an Authority Having Jurisdiction?

The authority having jurisdiction is the agency responsible for enforcing the applicable building requirements for a particular project.

The AHJ can determine:

• Which permit procedures apply
• What documents must be submitted
• Whether the plans contain sufficient information
• Whether applicable compliance forms are complete
• Whether plan-check corrections are required
• When construction inspections are required
• Whether required documentation has been provided before closeout

Most AHJs are associated with local city or county government.

However, special building types can have different enforcement authorities.

Knowing the correct AHJ is one of the first steps in determining how a project will move through permitting.

Does the California Energy Commission Enforce Title 24?

The California Energy Commission develops and administers California’s Building Energy Efficiency Standards, but it does not ordinarily perform direct enforcement for typical local building projects.

The California Energy Commission’s role includes:

• Developing the Energy Code
• Updating the standards
• Publishing compliance manuals
• Publishing reference appendices
• Providing compliance forms and guidance
• Establishing approved compliance methods
• Providing Energy Code technical support
• Supporting statewide implementation

Local enforcement agencies then apply the standards to individual projects.

This creates an important separation:

The California Energy Commission establishes the Energy Code. The authority having jurisdiction enforces it on the project.

For current statewide information, review the California Energy Commission Building Energy Efficiency Standards.

What Does the California Building Standards Commission Do?

The California Building Standards Commission has a different role.

It administers, coordinates, approves, codifies, and publishes California’s broader Building Standards Code, commonly known as Title 24.

Title 24 contains multiple parts covering different aspects of construction.

The California Building Standards Commission therefore helps oversee the broader statewide code system, but it does not normally act as the local building inspector for an ordinary private construction project.

The Commission itself explains that enforcement is generally handled by the local government building or planning department with jurisdiction over the property.

Title 24 Is More Than the Energy Code

The phrase “Title 24” is often used casually to mean California energy requirements.

Technically, Title 24 is the entire California Building Standards Code.

The Building Energy Efficiency Standards are primarily located in:

Title 24, Part 6.

Other parts of Title 24 address subjects such as:

• Building construction
• Residential construction
• Electrical systems
• Mechanical systems
• Plumbing
• Existing buildings
• CALGreen
• Other building requirements

Different agencies can therefore have responsibilities for different portions of Title 24.

Alternative Energy Systems focuses on California energy-compliance calculations and documentation rather than claiming responsibility for enforcing every part of the California Building Standards Code.

Who Enforces the Energy Portion of Title 24?

For an ordinary project, the local enforcement agency reviews the energy-compliance documentation as part of the overall permit package.

That can include checking whether:

• The correct compliance documents were submitted
• The project address is correct
• The building classification is correct
• The climate zone is correct
• The energy report matches the plans
• The windows match the report
• The insulation requirements are shown on the plans
• The HVAC information is coordinated
• Ventilation requirements are addressed
• Water-heating information is consistent
• Lighting requirements are documented when applicable
• Required verification measures are identified

The enforcement agency can issue corrections when this information is missing, contradictory, incomplete, or based on an incorrect project scope.

Who Reviews Title 24 During Plan Check?

The plans examiner or other authorized building-department reviewer typically evaluates the Title 24 documentation during plan review.

The reviewer can compare the Certificate of Compliance and related energy documents with the architectural, mechanical, electrical, and other construction plans.

For example, the reviewer may identify that:

• The energy report shows different windows than the plans
• The report uses a different conditioned floor area
• The wall insulation does not match the sections
• The HVAC equipment differs from the mechanical schedule
• The water-heating system is inconsistent
• Commercial lighting information is incomplete
• Required compliance forms are missing

These issues can result in plan-check corrections before a permit is issued.

What Happens During Title 24 Plan Review?

A typical energy-related plan review can involve several steps.

1. Permit Documents Are Submitted

The project team submits the plans and applicable compliance documentation to the enforcement agency.

2. The Plans Examiner Reviews the Package

The reviewer checks the drawings and supporting documents for compliance with applicable requirements.

3. Energy Documentation Is Compared With the Plans

Energy-related requirements should correspond to the actual building design.

4. Corrections May Be Issued

The building department may request clarification, missing information, or revised documentation.

5. The Project Team Responds

The architect, designer, engineer, energy consultant, or another responsible professional addresses comments within their respective scope.

6. Revised Documents Are Reviewed

The enforcement agency reviews the corrections before approving the permit package.

A well-coordinated report can make this process significantly easier because the energy documentation and construction plans communicate the same project.

Does a Title 24 Consultant Enforce the Code?

No.

A Title 24 consultant helps demonstrate compliance but does not normally act as the enforcement authority.

Alternative Energy Systems can:

• Review the project scope
• Review plans
• Identify missing energy-related information
• Prepare applicable calculations
• Prepare compliance documentation
• Coordinate energy measures with the plans
• Review building-department corrections
• Revise energy documentation when necessary

AES does not issue the building permit and does not replace the authority having jurisdiction.

This distinction helps establish clear responsibility during the permit process.

Does the Architect Enforce Title 24?

No.

An architect may be responsible for designing and coordinating the project but does not normally serve as the governmental enforcement agency.

The architect or designer can help make sure the plans show the energy features represented in the Title 24 documentation.

That can include:

• Wall assemblies
• Roof assemblies
• Insulation
• Windows
• Exterior doors
• Other applicable energy notes

The building department then reviews those documents.

Does the Contractor Enforce Title 24?

No.

Contractors are responsible for performing work according to the approved plans, specifications, applicable building requirements, and their contractual scope.

They can play a critical role in compliance by correctly installing:

• Insulation
• Windows
• Roof assemblies
• HVAC equipment
• Ductwork
• Ventilation systems
• Water-heating equipment
• Lighting
• Controls

However, enforcement authority still belongs to the applicable governmental agency.

Who Enforces Title 24 During Construction?

During construction, building inspectors working for the enforcement agency can inspect applicable work.

The inspector may evaluate whether the installed project corresponds to:

• The approved plans
• Approved energy documentation
• Applicable installation requirements
• Required compliance forms
• Applicable verification or acceptance documentation

An energy-related requirement is therefore not finished simply because it passed plan review.

The specified features still have to be constructed or installed.

What Energy Documents May Be Used During Enforcement?

The Energy Code uses different compliance documents at different stages of a project.

For applicable single-family projects, these can include:

• Certificates of Compliance
• Certificates of Installation
• Certificates of Verification when required

Nonresidential and multifamily projects can have their own applicable compliance documentation.

The important principle is that compliance continues from design into construction.

The documents can identify:

• What was designed
• What was installed
• What was verified when separate verification is required
• What was acceptance tested when applicable

The enforcement agency can use these documents during plan review and inspections.

What Is a Certificate of Compliance?

A Certificate of Compliance documents the energy-related characteristics and compliance measures associated with the proposed design.

It is generally part of the permit-submittal process.

Depending on the project, the documentation can identify:

• Building characteristics
• Envelope requirements
• Windows
• Mechanical systems
• Water heating
• Lighting
• Other applicable measures

The enforcement agency reviews the document together with the plans.

What Is a Certificate of Installation?

Installation documentation addresses applicable energy-related features or systems actually installed during construction.

The applicable installer or contractor completes the required installation documentation within the scope established by the Energy Code.

These documents help connect the approved design with what was actually built.

What Is a Certificate of Verification?

Certain projects require separate field verification or diagnostic testing.

When required, the applicable verification documentation records the results of that process.

Verification can involve measures associated with:

• Duct systems
• Airflow
• Mechanical equipment
• Other applicable performance-sensitive features

The field-verification professional does not replace the building department.

Instead, the verification documentation becomes part of the evidence used to demonstrate compliance.

Who Performs Field Verification?

When field verification and diagnostic testing are required, an appropriately qualified professional completes the applicable verification work.

The energy consultant preparing the original calculations is not automatically the person who performs this separate verification.

This division of responsibility helps provide independent confirmation of applicable installed measures.

The enforcement agency can require the applicable verification documentation before project completion.

Who Performs Acceptance Testing?

Some nonresidential systems require acceptance testing.

Depending on the project, this may involve:

• Lighting controls
• Mechanical systems
• Other regulated nonresidential systems

The applicable acceptance-test technician performs the required testing.

Acceptance testing is separate from:

• Preparing the Title 24 report
• Designing the system
• Performing ordinary building-department inspections

The completed acceptance documentation can then be made available to the enforcement agency as required.

Are Public Schools Enforced Differently?

Some specialized buildings have enforcement structures that differ from an ordinary city or county permit project.

For example, applicable California public school projects can involve the Division of the State Architect as the authority having jurisdiction.

This is why the California Energy Commission describes most—but not all—authorities having jurisdiction as local city or county enforcement agencies.

If the project involves a specialized state-regulated facility, confirm which agency has jurisdiction before assuming the local building department is the final enforcement authority.

Are Hospitals and Other Specialized Facilities Different?

Certain specialized facilities can fall under state-agency jurisdiction rather than the ordinary city or county enforcement process.

The exact agency depends on the building type and legal jurisdiction.

When the project is a:

• Hospital
• Public school
• State-regulated facility
• Other specialized building

the project team should identify the correct enforcement agency before preparing the final permit package.

The local building department can often help identify the appropriate enforcement authority when it does not have jurisdiction.

Can Cities and Counties Adopt Stricter Energy Standards?

Yes, under applicable California procedures.

Local governmental agencies can adopt and enforce local energy standards that are more energy efficient than the statewide Energy Code when required findings and California Energy Commission approval procedures are satisfied.

These local standards are sometimes referred to as reach codes.

This means the statewide Title 24 requirements can be the baseline rather than the maximum requirement in every jurisdiction.

Before finalizing a project, determine whether the applicable jurisdiction has approved local energy amendments affecting the proposed work.

Who Enforces a Local Energy Amendment?

When a jurisdiction has legally adopted an applicable local energy standard, the local enforcement agency can enforce that requirement as part of its building permit process.

That is another reason project requirements should be checked against the actual jurisdiction rather than relying solely on plans prepared for a project in another city.

Can a Building Department Change Title 24 on Its Own?

A local jurisdiction cannot simply disregard statewide standards or invent enforceable energy requirements informally.

Local amendments must follow applicable California law and required adoption procedures.

Where locally adopted energy standards are more restrictive than statewide Part 6 requirements, the applicable approval and filing requirements must be satisfied before enforcement.

Project teams should distinguish between:

• Statewide Title 24 requirements
• Legally adopted local amendments
• Ordinary permit-submittal procedures

These are related but different concepts.

What Happens if the Building Department Disagrees With the Title 24 Report?

A building department can issue a correction when the submitted documentation does not adequately demonstrate compliance or does not match the plans.

Possible comments may involve:

• Incorrect forms
• Missing information
• Incorrect project scope
• Incorrect climate zone
• Window discrepancies
• Insulation discrepancies
• Mechanical-system conflicts
• Water-heating conflicts
• Lighting-control information
• Missing signatures
• Missing verification requirements

The appropriate response is to review the complete correction notice and current plans.

Do not automatically change one isolated number without understanding the reason for the correction.

Can AES Help With a Title 24 Correction?

Yes.

For an energy-related correction, send AES:

• The complete correction notice
• The latest architectural plans
• The previously submitted energy report
• Current mechanical plans when applicable
• Current electrical or lighting plans when applicable
• Updated equipment specifications
• A summary of project changes

AES can determine whether the correction requires:

• Revised calculations
• Updated compliance forms
• New specifications
• Plan coordination
• Clarification of the energy documentation

Does a Title 24 Report Guarantee Building Department Approval?

No.

A Title 24 report is one part of the permit package.

The building department can also review:

• Architectural requirements
• Structural requirements
• Electrical requirements
• Mechanical requirements
• Plumbing requirements
• Fire and life-safety provisions
• CALGreen requirements
• Other applicable codes

A correct energy report supports the energy portion of the permit process but cannot guarantee complete permit approval.

Can the Building Department Require a Revised Title 24 Report?

Yes.

A revised report may be needed when:

• The original calculations contain incorrect project information
• The report does not match the current plans
• The design changes during plan review
• The building department identifies missing energy information
• The mechanical system changes
• The window design changes
• The conditioned floor area changes

The revision should address the actual project condition rather than simply changing text to satisfy a comment.

What Happens if the Plans Change After the Permit Is Issued?

Changes during construction can also affect Title 24 compliance.

Notify the appropriate project professionals before substituting or changing:

• Windows
• Insulation
• Roof construction
• HVAC equipment
• Duct configuration
• Ventilation
• Water heating
• Commercial lighting
• Lighting controls

A significant change may require revised plans, revised energy documentation, or approval from the enforcement agency.

Who Enforces Title 24 for an ADU?

For a typical ADU project, the local city or county building department with jurisdiction generally enforces the applicable Energy Code requirements through plan review and inspections.

The project can involve:

• Building-envelope requirements
• Windows
• Insulation
• HVAC
• Ventilation
• Water heating
• Applicable verification

AES can prepare energy-compliance documentation for detached ADUs, attached ADUs, garage conversions, and other applicable residential projects.

Visit the ADU Title 24 page for additional information.

Who Enforces Title 24 for a Home Addition?

The local authority having jurisdiction generally reviews the addition as part of the building permit.

The reviewer can evaluate whether new:

• Conditioned floor area
• Walls
• Roofs
• Windows
• Insulation
• HVAC
• Ductwork

meet applicable energy requirements.

The energy report should correspond to the final addition plans.

Who Enforces Title 24 for Residential Remodels?

A residential alteration is generally enforced by the local authority having jurisdiction.

The energy requirements depend on what is being changed.

A remodel can trigger applicable requirements when it affects:

• Windows
• Exterior doors
• Insulation
• Roofing
• HVAC equipment
• Ducts
• Water heating
• Other regulated systems

Purely cosmetic work can be treated differently from an alteration of regulated energy components.

Who Enforces Title 24 for Commercial Buildings?

For most private commercial projects, the local city or county enforcement agency reviews and inspects the work.

Commercial compliance can involve:

• Building envelope
• Mechanical systems
• Ventilation
• Service water heating
• Interior lighting
• Exterior lighting
• Lighting controls
• Other regulated energy systems

Some systems may also require acceptance testing in addition to normal building-department inspection.

For related services, review Title 24 compliance services and Title 24 energy analysis.

Who Enforces Title 24 for Commercial Tenant Improvements?

A tenant improvement can fall under current Energy Code requirements even though the building itself already exists.

The local enforcement agency can review changes involving:

• Lighting
• Lighting controls
• HVAC equipment
• Ventilation
• Water heating
• Storefront glazing
• Other regulated components

The tenant, landlord, contractor, and design team should not assume an older Title 24 report for the shell building automatically covers new tenant work.

Who Enforces Title 24 for HVAC Replacement?

When an HVAC replacement requires a permit and triggers applicable Energy Code requirements, the authority having jurisdiction can review:

• Equipment information
• Efficiency
• Duct requirements
• Applicable controls
• Required compliance forms
• Applicable field verification

The contractor and applicable verification professional may complete required project documentation, while the building department retains enforcement responsibility.

Who Enforces Title 24 for Commercial Lighting?

The local enforcement agency can review applicable commercial lighting requirements during permit review and inspection.

The project may involve:

• Lighting power
• Fixture information
• Occupancy controls
• Automatic shutoff
• Daylighting controls
• Exterior lighting

Applicable acceptance testing may also be required.

What Energy Code Is Being Enforced Now?

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

Projects should therefore use the appropriate current:

• Code requirements
• Compliance forms
• Calculation methods
• Approved software when applicable
• Verification procedures

Do not assume that forms or calculations prepared under the previous 2022 Energy Code remain appropriate for a new permit application.

How Do You Know Which Building Department Has Jurisdiction?

Start with the project address and determine whether the property is:

• Inside an incorporated city
• In an unincorporated county area
• Part of a specialized state-regulated project

The permitting authority for the property should be confirmed before relying on local submittal requirements.

If the local agency is not the correct enforcement authority, it can often identify which agency has jurisdiction.

What if You Disagree With a Building Department Interpretation?

Questions about code interpretation should generally begin with the local building department.

Depending on the issue and jurisdiction, review may proceed through:

• The plans examiner
• The building official
• The jurisdiction’s appeal procedures
• Other applicable administrative review

A Title 24 consultant can provide technical information related to the energy calculations, but the consultant cannot overrule the authority having jurisdiction.

Why Early Title 24 Coordination Helps With Enforcement

It is easier to satisfy energy requirements when the report is prepared before the design is considered final.

Early review can identify:

• Missing window information
• Unclear insulation assemblies
• Undecided HVAC equipment
• Duct conditions
• Ventilation requirements
• Water-heating issues
• Commercial lighting information
• Potential verification measures

Addressing these items before formal plan check can reduce avoidable corrections.

Before sending documents, review what AES will need from you.

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides professional Title 24 calculations, compliance documentation, 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 buildings
• Commercial construction
• Tenant improvements
• HVAC projects
• Commercial lighting projects
• Plan-check corrections
• Energy-report revisions

AES prepares the energy-compliance portion of the project so it can be reviewed by the appropriate enforcement agency.

Learn more through the About Us page or review company background on the clients page.

Get Help With Title 24 Before Building Department Review

Call (626) 365-1518 | Alternative Energy Systems

Understanding Who Enforces Title 24 can make the permit process much clearer.

For most projects:

• The California Energy Commission establishes the Energy Code
• The California Building Standards Commission administers the broader Title 24 code system
• The local authority having jurisdiction enforces the applicable requirements
• The plans examiner reviews compliance before permit issuance
• The contractor installs the required systems and materials
• Qualified professionals perform required verification or acceptance testing
• The building inspector reviews applicable construction in the field

Alternative Energy Systems can prepare and coordinate the Title 24 energy documentation that supports this process.

Call (626) 365-1518 if you need:

• A new Title 24 report
• Energy calculations
• Compliance forms
• A review of existing energy documentation
• A revision after plans change
• Help responding to energy-related plan-check comments

You may also 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: Who Enforces Title 24?

Who Enforces Title 24?

For most California construction projects, the city or county building department serving as the authority having jurisdiction enforces the applicable Title 24 requirements through plan review, permit issuance, inspections, and project closeout.

Does the California Energy Commission enforce Title 24?

The California Energy Commission develops and administers the Building Energy Efficiency Standards but does not ordinarily directly enforce the Energy Code on typical local construction projects.

Who enforces Title 24, Part 6?

The authority having jurisdiction generally enforces the Energy Code as part of the overall building permit process.

Who is the authority having jurisdiction?

For most projects, it is the city or county building department responsible for permits and inspections at the project location. Certain specialized buildings can have another state or public agency as the AHJ.

Who reviews the Title 24 report?

The applicable building-department plans examiner or other authorized reviewer can review the energy documentation during plan check.

Who issues Title 24 corrections?

The enforcement agency can issue plan-check comments when the energy documents are incomplete, inconsistent, or do not demonstrate the applicable requirements.

Does a Title 24 consultant approve the project?

No. The consultant prepares energy-compliance documentation. The applicable enforcement authority reviews the permit package.

Does AES enforce Title 24?

No. AES provides Title 24 energy-compliance consulting, calculations, documentation, and revisions.

Does the architect enforce Title 24?

No. Architects and designers coordinate applicable requirements with the building design, while enforcement belongs to the authority having jurisdiction.

Does the contractor enforce Title 24?

No. Contractors construct the project according to the approved documents and applicable requirements.

Who inspects Title 24 work?

Building inspectors working for the applicable enforcement agency inspect construction within their jurisdiction and scope.

Who verifies HVAC or duct requirements?

When separate field verification or diagnostic testing is required, the appropriate qualified verification professional performs that work and prepares the applicable documentation.

Who performs commercial acceptance testing?

When required, an appropriately qualified acceptance-test technician performs the applicable system testing.

Who enforces Title 24 for an ADU?

For a typical ADU, the local city or county building department generally enforces the applicable Energy Code requirements.

Who enforces Title 24 for a commercial building?

Most private commercial projects are enforced by the applicable city or county building department, although specialized facilities can have different authorities.

Who enforces Title 24 for schools?

Certain California public school projects can fall under the jurisdiction of the Division of the State Architect rather than an ordinary local building department.

Are hospitals always enforced by the city?

Not necessarily. Specialized facilities can fall under state-agency jurisdiction, so the correct enforcement authority should be identified for the specific project.

Can a city enforce standards stricter than statewide Title 24?

A local government can adopt qualifying local energy standards through the applicable California approval process. Once properly adopted, the local enforcement agency can enforce them.

Can the building department require a revised energy report?

Yes. A revision may be required when the report does not match the plans, project information changes, or additional compliance information is necessary.

Can the building department reject a Title 24 report?

The enforcement agency can require corrections when the submitted documentation does not adequately demonstrate compliance with the applicable requirements.

Does a Title 24 report guarantee permit approval?

No. Energy compliance is one part of the overall permit review.

What happens after the Title 24 report passes plan check?

The project proceeds through construction, applicable installation documentation, required verification or acceptance testing, and building-department inspections.

What if the contractor changes equipment after permit approval?

Energy-related substitutions should be reviewed because they can affect the approved Title 24 documentation and may require revised plans or calculations.

What Energy Code is currently being enforced?

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

Who should I contact about a local Title 24 interpretation?

Start with the building or planning department that has jurisdiction over the property.

Who should I contact for project-specific Title 24 calculations?

Call Alternative Energy Systems at (626) 365-1518 and provide the current plans and project information for review.

What Are the Current Title 24 Standards?

Call (626) 365-1518 | Alternative Energy Systems

What Are the Current Title 24 Standards is an important question for homeowners, contractors, architects, designers, developers, property managers, and commercial building owners preparing construction documents in California.

The current statewide Building Energy Efficiency Standards are the 2025 California Energy Code. For applicable permit applications filed on or after January 1, 2026, projects must comply with the 2025 Energy Code.

The Energy Code is contained primarily in California Code of Regulations, Title 24, Part 6, with associated administrative requirements in Part 1.

The current standards establish energy-efficiency requirements for applicable:

• Newly constructed residential buildings
• Newly constructed multifamily buildings
• Newly constructed nonresidential buildings
• Additions to existing buildings
• Alterations to existing buildings
• Building-envelope components
• Heating and cooling systems
• Ventilation
• Water heating
• Lighting and controls
• Solar and battery systems when applicable
• Other regulated energy-related systems

The exact requirements are not identical for every project.

Building type, climate zone, construction scope, existing conditions, equipment, and the selected compliance method all influence what must be shown in the final Title 24 documentation.

Alternative Energy Systems brings more than 30 years of California energy-compliance experience to residential, multifamily, mixed-use, and commercial projects.

Call (626) 365-1518 if you need Title 24 calculations or want to determine which current requirements apply to your project.

The Current Energy Code Is the 2025 California Energy Code

California updates its Building Energy Efficiency Standards on a three-year cycle.

The current edition is the 2025 Energy Code.

Although it is called the 2025 edition, it became effective statewide on January 1, 2026.

That means the two dates serve different purposes:

• 2025 identifies the code edition
• January 1, 2026 is its statewide effective date

The previous 2022 Energy Code generally applied to applicable permit applications under the prior code cycle.

Projects entering permitting now should not automatically rely on forms, calculations, equipment assumptions, or compliance reports prepared under an older edition.

Which Projects Use the Current Standards?

The current Energy Code contains requirements for residential and nonresidential buildings involving:

• New construction
• Additions
• Alterations

Projects can include:

• New homes
• ADUs
• Garage conversions
• Room additions
• Residential remodels
• Apartment buildings
• Multifamily alterations
• Mixed-use projects
• Office buildings
• Retail spaces
• Restaurants
• Warehouses
• Commercial tenant improvements
• HVAC alterations
• Lighting projects

A limited alteration will not necessarily require the same documentation as a newly constructed building.

The project scope determines which sections and forms apply.

The Current Standards Have Three Main Compliance Layers

One of the easiest ways to understand the current Energy Code is to separate it into three broad categories.

Mandatory Requirements

Mandatory provisions establish requirements that apply according to the applicable building and project scope.

These requirements cannot simply be traded away through a performance calculation.

Performance Compliance

Performance compliance evaluates the building using approved energy-modeling methods.

The proposed design is compared against an established energy budget based on factors such as:

• Building type
• Climate zone
• Project characteristics

Performance compliance allows different energy measures to interact and can provide design flexibility.

Prescriptive Compliance

The prescriptive approach provides specified requirements for applicable components and systems.

Instead of relying primarily on whole-building tradeoffs, the project follows the applicable prescriptive package.

For more information about the calculation process, review Title 24 energy calculations.

Mandatory Requirements Establish the Baseline

Mandatory requirements establish minimum provisions that apply within their defined project scope.

Depending on the building, they can involve areas such as:

• Building-envelope construction
• Mechanical systems
• Ventilation
• Water heating
• Lighting
• Electrical provisions
• Other regulated systems

A performance calculation should not be interpreted as permission to ignore applicable mandatory requirements.

The complete compliance package needs to address both the mandatory provisions and the selected compliance path.

Performance Standards Vary by Climate Zone and Building Type

California has 16 building climate zones.

The performance energy budget can vary according to:

• Climate zone
• Building type

This allows the Energy Code to account for California’s very different climatic conditions.

A coastal building does not necessarily experience the same heating and cooling conditions as an inland valley, desert, or mountain building.

For more information about this relationship, review the climate-zone requirements applicable to the actual project location rather than relying on a generic statewide assumption.

Prescriptive Standards Provide a Defined Compliance Path

Prescriptive compliance provides another way to demonstrate compliance.

Depending on the project, prescriptive requirements can address:

• Insulation
• Windows
• Roof characteristics
• Heating and cooling systems
• Water heating
• Lighting
• Controls
• Other regulated systems

Prescriptive requirements can vary according to building category and climate zone.

A specification used successfully on one project should therefore not automatically be copied to another building without review.

Current Standards for the Building Envelope

The building envelope remains a major part of Title 24 compliance.

Depending on the project, the current standards can address:

• Exterior walls
• Roof assemblies
• Ceilings
• Floors
• Attics
• Windows
• Glazed exterior doors
• Other thermal boundaries

The energy documentation should accurately represent what is shown in the construction plans.

If the report shows one wall, roof, window, or insulation condition while the plans show another, the project may need correction.

Current Insulation Requirements Depend on the Project

There is no single insulation value that applies universally to every California building.

The applicable requirements can depend on:

• Building type
• Climate zone
• Wall assembly
• Roof assembly
• Ceiling configuration
• Floor configuration
• Compliance approach

The energy calculations and architectural sections should describe compatible assemblies.

Changing insulation after the report is prepared can require review.

Current Window Standards Address Energy Performance

Windows can significantly affect building energy performance.

Applicable Title 24 documentation may address:

• Window area
• Orientation
• U-factor
• Solar heat gain coefficient
• Glazed exterior doors

Product selections should correspond to the performance characteristics represented in the energy report.

Contractors and owners should confirm window specifications before ordering products.

Current Roof Requirements Can Affect Compliance

Roof-related energy requirements can involve:

• Roof insulation
• Ceiling insulation
• Attic construction
• Roofing characteristics
• Cool-roof provisions when applicable

The actual requirements depend on project type, climate zone, roof assembly, and compliance method.

Current HVAC Standards Continue to Emphasize Efficient Equipment

Heating and cooling systems remain central to the Energy Code.

Applicable requirements can involve:

• Equipment type
• Heating efficiency
• Cooling efficiency
• Heat-pump systems
• Controls
• Duct systems
• Other mechanical measures

The 2025 code cycle expands the role of efficient heat-pump technology in several building categories.

The exact requirement depends on whether the project is single-family, multifamily, nonresidential, new construction, or an alteration.

The 2025 Standards Expand Heat-Pump Use

Heat pumps are an important part of the current Energy Code.

The 2025 standards expand or encourage heat-pump technology for:

• Space conditioning
• Water heating
• Certain residential applications
• Some multifamily applications
• Selected nonresidential applications

This does not mean every project automatically has one identical heat-pump requirement.

The correct provision depends on building type, construction scope, system configuration, and compliance path.

Some Existing Commercial HVAC Replacements Have New Requirements

The 2025 Energy Code also includes updated requirements affecting certain existing commercial buildings when qualifying rooftop HVAC equipment reaches end of life and is replaced.

These provisions apply to specified equipment and building categories rather than every HVAC replacement in California.

Affected projects can include certain:

• Retail buildings
• Schools
• Office buildings
• Libraries

A commercial HVAC replacement should therefore be evaluated according to the actual equipment size, building use, and applicable code section.

Duct Requirements Remain Part of Energy Compliance

Duct systems can affect energy performance.

Applicable requirements can involve:

• Duct location
• Duct insulation
• Duct sealing
• Airflow-related requirements
• Applicable field verification

Do not assume that changing the duct design has no effect because the HVAC equipment itself remains unchanged.

Mechanical-system revisions should be coordinated with the energy report.

Current Ventilation Standards Are Stronger in Important Areas

The 2025 Energy Code includes updated ventilation provisions.

Ventilation is important because energy-efficient buildings must also provide appropriate indoor air quality.

Depending on building type, the requirements can involve:

• Whole-building ventilation
• Local exhaust
• Outdoor-air systems
• Energy recovery ventilation
• Other applicable mechanical ventilation measures

The 2025 cycle includes strengthened multifamily ventilation requirements.

Ventilation should therefore be coordinated with the mechanical plans and Title 24 documentation rather than treated as a separate afterthought.

Water-Heating Standards Continue to Evolve

Water heating is another significant building energy use.

Current requirements can address:

• Equipment type
• Efficiency
• Heat-pump water heaters
• Hot-water distribution
• Pipe insulation
• Central systems
• Individual systems

The 2025 Energy Code expands heat-pump water-heating provisions in several building categories.

Current Single-Family Standards Include Electric-Ready Requirements

The 2025 Energy Code includes electric-ready requirements for certain newly constructed single-family buildings when specified gas or propane appliances are installed.

Depending on the design, electric-ready provisions can relate to future conversion of:

• Space heating
• Water heating
• Cooking
• Clothes drying

These requirements are intended to make future conversion to efficient electric equipment easier.

They do not apply identically to every addition, alteration, or all-electric project.

The actual design should be reviewed against the applicable code provisions.

Some New Single-Family Buildings Must Be Battery-Ready

The 2025 Energy Code also contains battery energy storage system readiness requirements for certain newly constructed single-family buildings.

The applicability depends on specific project and electrical-service conditions.

This is another example of why a current Title 24 report should be based on the actual project rather than an older generic checklist.

Current Multifamily Standards Include Significant Updates

The 2025 cycle includes several updates affecting multifamily buildings.

Depending on the project, these can involve:

• Heat-pump water heating
• Heat-pump water-heater readiness
• Water-heating ventilation
• Pipe insulation
• Building-envelope efficiency
• Energy recovery ventilation
• Solar photovoltaic calculations
• Battery-energy-storage calculations
• Lighting requirements
• Pool and spa heating

The correct multifamily compliance documentation depends on the project scope and building configuration.

Current Nonresidential Standards Include Major Mechanical Updates

The current nonresidential standards include updated mechanical provisions.

Examples include:

• Heat-pump water-heater requirements in applicable newly constructed buildings
• Heat-pump baselines for certain multizone systems
• Updated HVAC efficiency requirements
• Updated controls
• Envelope-efficiency improvements

Office, school, retail, restaurant, warehouse, assembly, and other commercial projects should be reviewed according to their individual building type and systems.

Commercial Kitchens Can Have Electric-Ready Requirements

The 2025 Energy Code establishes electric-ready requirements for applicable commercial kitchens.

The purpose is to make future conversion to electric cooking equipment more practical.

This does not mean every restaurant or commercial kitchen must immediately replace all fuel-fired cooking appliances.

The exact requirement depends on the applicable new construction or project scope.

Lighting Remains an Important Part of Current Commercial Standards

Nonresidential lighting continues to be regulated under the Energy Code.

Applicable requirements can involve:

• Interior lighting power
• Fixture wattage
• Space use
• Exterior lighting
• Lighting controls
• Automatic shutoff
• Occupancy controls
• Daylighting controls

The 2025 cycle also includes updates intended to clarify and simplify portions of the lighting requirements.

Commercial lighting plans should remain coordinated with the energy documentation.

Solar Requirements Remain Part of the Current Energy Code

Solar photovoltaic requirements continue to apply to qualifying projects.

The 2025 Energy Code updates solar provisions for certain multifamily and nonresidential buildings.

Applicability depends on factors such as:

• Building type
• New construction status
• Roof conditions
• Applicable exceptions
• Other project-specific conditions

Do not assume every project has the same solar requirement.

Battery-Energy-Storage Requirements Have Also Been Updated

The 2025 standards include updated battery-energy-storage provisions in applicable building categories.

These changes are intended to improve the way buildings interact with onsite solar generation and the electrical grid.

Applicable requirements differ among:

• Single-family buildings
• Multifamily buildings
• Nonresidential buildings

The code can distinguish between:

• Battery readiness
• Battery installation requirements
• Solar and battery sizing requirements

The actual project should be reviewed before determining which provision applies.

Some Assembly Buildings Now Have Expanded Solar and Storage Requirements

The 2025 nonresidential standards expand applicable solar photovoltaic and battery-energy-storage provisions to additional assembly building types.

These can include certain buildings used for:

• Events and exhibits
• Religious worship
• Sports and recreation

Applicability still depends on the complete Energy Code provisions and project-specific conditions.

Current Standards Address Grid Flexibility as Well as Efficiency

Modern Title 24 requirements increasingly consider not only how much energy a building uses but also how building systems interact with the electrical grid.

Current standards can include strategies involving:

• Heat pumps
• Electric readiness
• Solar generation
• Battery storage
• Load flexibility
• Controls

This reflects the changing relationship between individual buildings and California’s larger energy system.

The Current Standards Still Depend on Climate Zone

California continues to use 16 building climate zones.

Climate-sensitive requirements can affect:

• Building-envelope performance
• Insulation
• Windows
• Solar heat gain
• Roof characteristics
• Heating and cooling analysis

A report should therefore use the correct project location and climate zone.

Current Standards Are Different for Single-Family, Multifamily, and Nonresidential Buildings

One of the most important changes in recent Energy Code organization is the clearer separation of major building categories.

A project should first be classified correctly as:

• Single-family residential
• Multifamily
• Nonresidential

The applicable compliance manual, forms, requirements, and calculations depend on this classification.

A detached home should not automatically use the same assumptions as an apartment building.

An apartment project should not automatically use the same forms as a retail tenant improvement.

Current Standards for Additions Depend on the New Work

An addition can introduce:

• New conditioned floor area
• New exterior walls
• New windows
• New roof assemblies
• New insulation
• New or extended HVAC systems
• Ductwork
• Ventilation
• Water heating

The applicable requirements are based on the project scope rather than simply the age of the original building.

Current Standards for Alterations Depend on What Is Being Changed

Existing buildings can trigger current Energy Code requirements when regulated components are altered.

Examples can involve:

• Window replacement
• Roofing work
• Insulation changes
• HVAC replacement
• Duct alterations
• Water-heating replacement
• Commercial lighting alterations
• Control upgrades

A limited alteration does not necessarily require the same whole-building analysis as new construction.

Applicable alteration requirements and forms should be identified first.

Current Standards Do Not Mean Every Existing Building Must Be Rebuilt

The effective date of a new Energy Code does not mean every existing California building suddenly has to be upgraded completely.

The standards apply according to the construction project and code-defined scope.

Existing buildings can remain in service without automatically being reconstructed to each new code cycle.

Current requirements generally become relevant when covered construction, additions, alterations, or other regulated work occurs.

Field Verification Can Still Be Required

Some current Title 24 measures require separate field verification or diagnostic testing.

Depending on the project, this may involve:

• Duct systems
• Airflow
• Mechanical equipment
• Other performance-sensitive measures

The Title 24 report can identify applicable verification requirements.

The report itself does not replace the required field verification.

Commercial Acceptance Testing Can Also Be Required

Applicable nonresidential projects may require acceptance testing for certain installed systems and controls.

This can include applicable:

• Lighting controls
• Mechanical systems
• Other regulated systems

Acceptance testing is separate from preparation of the original Title 24 calculations.

The project team should identify these requirements before construction is complete.

Current Title 24 Standards and CALGreen Are Not the Same Thing

Title 24 includes multiple parts of California’s Building Standards Code.

The Energy Code is primarily Part 6.

CALGreen is Part 11.

The two can overlap in broader sustainability goals, but they contain different requirements.

A Title 24 energy report should not be assumed to satisfy every CALGreen requirement.

For additional context, review Title 24 vs. CALGreen.

Why Using the Current Forms Matters

A project can have accurate architectural drawings and still encounter problems if the wrong compliance forms are used.

New code cycles can change:

• Forms
• Terminology
• Calculation procedures
• Compliance software
• Verification requirements

Do not assume a form saved from a previous project remains current.

The report should use the documents appropriate to the applicable Energy Code edition.

Why Current Compliance Software Matters

Performance calculations are completed using approved compliance methods.

The California Energy Commission establishes rules governing energy-modeling software used for compliance.

Current software must reflect the 2025 Energy Code’s:

• Calculation procedures
• Reference assumptions
• Performance requirements
• Reporting requirements

An old calculation produced under a previous code cycle should not automatically be treated as current.

What Happens if Your Existing Report Was Prepared Under the 2022 Standards?

Send AES:

• The existing report
• The latest plans
• The project address
• Current specifications
• Available permit information

AES can review whether the previous report still corresponds to the applicable permit circumstances or whether new calculations and forms are needed.

Do not simply change the date on an older compliance report.

What Information Is Needed for a Current Title 24 Report?

Helpful project documents may include:

• Floor plans
• Exterior elevations
• Building sections
• Roof plans
• Window schedules
• Window specifications
• Insulation details
• HVAC equipment information
• Duct locations
• Ventilation information
• Water-heating information
• Commercial lighting plans
• Commercial lighting-control plans
• Existing Title 24 documentation
• Building-department corrections

Not every item is required for every project.

Before sending documents, review what AES will need from you.

How Do You Know Which Current Requirements Apply to Your Project?

Start with five questions:

1. What type of building is it?
2. Is the work new construction, an addition, or an alteration?
3. What is the project climate zone?
4. Which building components and systems are changing?
5. Which compliance path applies?

Those answers help identify the relevant requirements.

The project can then be evaluated for:

• Mandatory measures
• Prescriptive requirements
• Performance compliance
• Applicable verification
• Applicable acceptance testing

Why Early Review of the Current Standards Matters

Waiting until the permit package is finished before addressing Title 24 can create unnecessary revisions.

Early energy review can identify:

• Missing insulation information
• Window-performance issues
• HVAC conflicts
• Ventilation questions
• Water-heating requirements
• Commercial lighting issues
• Solar or battery requirements when applicable
• Verification measures

Resolving these items before submittal can make the energy documentation easier to coordinate with the plans.

What if the Plans Change After the Current Report Is Prepared?

Notify AES when the project changes:

• Floor area
• Building geometry
• Windows
• Insulation
• Roof assemblies
• HVAC equipment
• Duct locations
• Ventilation
• Water heating
• Lighting
• Controls
• Solar or battery systems

The existing calculations can then be reviewed to determine whether revised forms or analysis are necessary.

What if the Building Department Requests Corrections?

Send AES:

• The complete correction notice
• The latest plan set
• The previously submitted energy report
• Updated mechanical plans
• Updated electrical or lighting plans when applicable
• Current product specifications
• A summary of design changes

AES can review whether the comment requires:

• Revised calculations
• Updated forms
• Additional specifications
• Plan coordination
• Clarification of current requirements

Why Choose Alternative Energy Systems?

Alternative Energy Systems provides professional Title 24 calculations, compliance documentation, revisions, and 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
• Office tenant improvements
• Retail projects
• Restaurant projects
• Warehouse alterations
• HVAC projects
• Commercial lighting projects
• Plan-check corrections

AES reviews the current plans and applies the Energy Code appropriate to the project rather than relying on outdated reports or assumptions from another building.

Learn more through the About Us page or review company background on the clients page.

Get Help With the Current Title 24 Standards

Call (626) 365-1518 | Alternative Energy Systems

Understanding What Are the Current Title 24 Standards starts with recognizing that the current statewide Energy Code is the 2025 edition, effective for applicable permit applications filed on or after January 1, 2026.

The current standards include:

• Mandatory energy-efficiency requirements
• Prescriptive compliance options
• Performance compliance options
• Climate-zone-specific energy budgets
• Building-envelope requirements
• Window requirements
• HVAC requirements
• Ventilation requirements
• Water-heating requirements
• Lighting and control requirements
• Expanded heat-pump provisions
• Electric-ready provisions in applicable projects
• Solar and battery-storage requirements in applicable projects
• Verification and acceptance-testing requirements where applicable

The exact combination depends on the building and scope.

Alternative Energy Systems can review your plans and determine what energy-compliance documentation is needed for the current code cycle.

Call (626) 365-1518 or begin through the contact page.

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

For official current statewide information, review the California Energy Commission 2025 Building Energy Efficiency Standards.

Frequently Asked Questions: What Are the Current Title 24 Standards?

What Are the Current Title 24 Standards?

The current California Energy Code is the 2025 Building Energy Efficiency Standards, primarily contained in Title 24, Part 6. They apply to applicable permit applications filed on or after January 1, 2026.

When did the current standards take effect?

The 2025 Energy Code took effect statewide on January 1, 2026.

Why is it called the 2025 Energy Code if it became effective in 2026?

2025 identifies the edition. January 1, 2026 is the effective date.

What was the previous Title 24 Energy Code?

The prior major edition was the 2022 Energy Code, which took effect January 1, 2023.

Do the current standards apply to new homes?

Yes. Applicable newly constructed single-family buildings are subject to the current residential Energy Code requirements.

Do the current standards apply to ADUs?

Yes. New ADUs and applicable conversions, additions, or alterations can be subject to current Title 24 requirements.

Do the current standards apply to multifamily buildings?

Yes. California has dedicated 2025 multifamily requirements and compliance guidance.

Do the current standards apply to commercial buildings?

Yes. Applicable newly constructed nonresidential buildings, additions, and alterations are subject to current Energy Code provisions.

Do existing buildings have to be completely upgraded?

No. A new code cycle does not automatically require every existing building to be completely rebuilt. Requirements apply according to the construction or alteration scope.

What are mandatory Title 24 requirements?

Mandatory requirements establish baseline provisions that apply within their defined building and project scope regardless of whether prescriptive or performance compliance is used.

What is prescriptive compliance?

Prescriptive compliance follows applicable component and system requirements established by the Energy Code.

What is performance compliance?

Performance compliance uses approved energy modeling to compare the proposed building against an applicable energy budget while allowing certain design tradeoffs.

Do the current standards vary by climate zone?

Yes. California has 16 building climate zones, and performance budgets and certain prescriptive requirements vary by climate zone and building type.

Do the current standards include heat pumps?

Yes. The 2025 cycle expands or encourages efficient heat-pump technology for several residential, multifamily, and nonresidential applications.

Are new homes required to be electric-ready?

Certain newly constructed single-family buildings have electric-ready requirements when specified gas or propane appliances are installed.

Are batteries required in every new home?

No. Battery-related provisions differ by building type and project conditions. Some new single-family projects have battery-ready requirements rather than a universal battery-installation requirement.

Do the current standards include solar requirements?

Yes. Solar photovoltaic requirements continue to apply to qualifying projects, and the 2025 code updates solar provisions for certain multifamily and nonresidential building types.

Do commercial buildings have battery-storage requirements?

Certain qualifying nonresidential projects have applicable battery-energy-storage requirements, subject to the specific Energy Code provisions and exceptions.

Are ventilation requirements part of the current standards?

Yes. Ventilation remains part of the Energy Code, and the 2025 cycle includes strengthened requirements in important building categories.

Are water-heating requirements part of the current standards?

Yes. Water heating remains a major regulated system, and the 2025 cycle expands certain heat-pump water-heating requirements.

Does Title 24 still regulate commercial lighting?

Yes. Commercial lighting power and lighting controls remain part of nonresidential energy compliance.

Are Title 24 and CALGreen the same?

No. The Energy Code is primarily Title 24, Part 6, while CALGreen is Title 24, Part 11.

Can I use a 2022 Title 24 report for a current project?

Do not assume so. The report, permit timing, plans, forms, calculations, and applicable code cycle should be reviewed first.

Do current Title 24 reports require current software?

Performance calculations should use compliance methods and software approved for the applicable current Energy Code.

How do I know which current requirements apply to my project?

The answer depends on building type, project scope, climate zone, systems involved, and compliance method. AES can review the current plans and determine what information is needed.

How do I get started?

Call Alternative Energy Systems at (626) 365-1518 and provide the current plans and project information for review.

Why Do Title 24 Standards Vary by Climate Zone?

Call (626) 365-1518 | Alternative Energy Systems

Why Do Title 24 Standards Vary by Climate Zone is an important question because California does not experience one uniform climate. A building near the coast can face very different heating, cooling, solar, and outdoor-temperature conditions from a building in an inland valley, desert community, or mountain region.

California addresses those differences through 16 building climate zones used by the Building Energy Efficiency Standards.

Climate zone can affect how certain energy requirements are applied to:

• Exterior walls
• Roof and ceiling assemblies
• Insulation
• Windows
• Glazed exterior doors
• Roof characteristics
• Heating systems
• Cooling systems
• Duct systems
• Other climate-sensitive building features

The goal is not to make one part of California easier and another harder.

The goal is to establish energy requirements that respond to the actual conditions a building is expected to experience.

A strategy that performs well in a mild coastal environment may not provide the same result in a hot inland climate or a cold mountain climate.

Alternative Energy Systems brings more than 30 years of California energy-compliance experience to residential, multifamily, mixed-use, and commercial projects.

Call (626) 365-1518 if you need Title 24 calculations prepared for a California project or want to confirm how climate zone affects the energy analysis.

California Uses 16 Building Climate Zones

California’s Energy Code recognizes 16 building climate zones.

These climate zones allow statewide energy standards to account for the significant climatic differences found across California.

That matters because buildings in different parts of the state can experience very different:

• Outdoor temperatures
• Heating demands
• Cooling demands
• Solar conditions
• Seasonal energy loads

Climate zone therefore becomes one of the basic inputs used when determining how a building is evaluated for energy compliance.

The California Energy Commission maintains an official Building Climate Zone tool and maps for identifying the applicable zone.

Why Doesn’t California Use One Energy Standard Everywhere?

A single identical energy prescription across the entire state would ignore important differences in how buildings actually use energy.

Consider two otherwise similar buildings.

One may spend much of the year responding to cooling loads.

Another may experience greater heating demand.

A third may exist in a relatively moderate coastal environment where heating and cooling conditions are different again.

Using exactly the same prescriptive requirements in every location could result in measures that are poorly matched to local conditions.

Climate zones allow the Energy Code to respond more intelligently.

The Energy Code Is Designed Around Local Conditions

California’s current Energy Code includes several layers of requirements.

Some mandatory requirements apply broadly to applicable buildings statewide.

Other requirements can depend on:

• Climate zone
• Building type
• Project scope
• Compliance method

This distinction is important.

Climate zone does not mean every rule changes when a building crosses from one zone into another.

Instead, certain climate-sensitive requirements and performance targets vary so the overall standards reflect local building-energy conditions.

Mandatory Requirements and Climate-Specific Requirements Are Different

A useful way to understand Title 24 is to separate statewide mandatory measures from climate-sensitive requirements.

Mandatory requirements establish baseline provisions that apply according to the applicable building and project scope.

Climate-sensitive requirements may change because local weather affects energy performance.

For example, climate zone can influence requirements involving:

• Building-envelope performance
• Fenestration
• Roof characteristics
• Heating and cooling performance
• Other climate-dependent measures

This provides consistency statewide while still allowing the Energy Code to respond to California’s regional differences.

Performance Energy Budgets Vary by Climate Zone

Under the performance approach, a proposed building is evaluated against an energy budget associated with the applicable building type and climate zone.

That means the performance target is not completely identical throughout California.

The energy model can account for conditions associated with the project’s climate region.

This helps the analysis reflect the energy demands expected at the building’s actual location.

A project in one climate zone therefore should not automatically use a performance model prepared for another climate zone.

Prescriptive Requirements Can Also Vary by Climate Zone

Climate differences can also affect prescriptive requirements.

Prescriptive compliance provides specific requirements or packages for applicable building components rather than relying entirely on whole-building tradeoffs.

Depending on the project, climate-sensitive prescriptive measures may involve:

• Insulation
• Windows
• Glazed doors
• Roof characteristics
• Mechanical systems
• Other applicable components

This means a product or assembly acceptable under one set of climate-zone requirements should not automatically be assumed to satisfy another.

Climate Zone Changes the Context of Building Performance

A building component does not perform in isolation.

Its effect depends partly on the environment surrounding the building.

For example, window performance interacts with:

• Outdoor temperature
• Solar exposure
• Window orientation
• Building design
• Heating and cooling systems

Insulation interacts with the temperature difference between the conditioned interior and exterior environment.

HVAC systems respond to the heating and cooling loads created by the building envelope and local climate.

Climate zone provides the framework for evaluating those relationships.

Hotter Areas Can Create Different Cooling Demands

In warmer inland and desert conditions, cooling can become a significant part of building energy use.

Design characteristics such as:

• Window area
• Solar heat gain
• Roof characteristics
• Insulation
• Cooling-equipment efficiency

can have significant effects on overall energy performance.

A measure that produces limited benefit in a mild climate can become more important where the building experiences greater cooling demand.

Cooler Areas Can Create Different Heating Demands

Cold-weather conditions can shift attention toward heating performance.

Relevant factors can include:

• Building-envelope insulation
• Window thermal performance
• Heating-system efficiency
• Duct conditions
• Other heat-loss characteristics

Again, the Energy Code does not assume that the same building faces identical loads everywhere in California.

Mild Coastal Areas Have Different Energy Characteristics

California’s coastal areas can have considerably different heating and cooling patterns from inland or mountain regions.

That can change the relative importance of certain energy-efficiency measures.

A requirement should therefore reflect the local building-energy environment rather than applying a desert or mountain assumption to every coastal building.

This is one of the fundamental reasons climate zones exist.

Climate Zone Can Affect Building-Envelope Requirements

The building envelope separates conditioned space from outdoor or unconditioned environments.

Because outdoor conditions vary across California, envelope performance can have different effects from one climate zone to another.

The envelope can include:

• Exterior walls
• Roofs
• Ceilings
• Floors
• Windows
• Exterior glazed doors

The energy analysis evaluates these components as part of the overall building design.

Insulation Requirements Can Be Climate Sensitive

Insulation reduces heat transfer through building assemblies.

Its effect depends partly on the conditions occurring outside the building.

Applicable insulation requirements can involve:

• Exterior walls
• Roofs
• Ceilings
• Attics
• Floors
• Other thermal boundaries

Different climate conditions can make particular envelope measures more or less important to overall performance.

That is why insulation requirements should be determined from the applicable code and project rather than copied from a different location.

Window Requirements Can Vary by Climate Zone

The California Energy Commission specifically identifies fenestration as an area where standards can depend on climate zone.

Window performance may involve:

• U-factor
• Solar heat gain coefficient
• Window area
• Orientation
• Glazed exterior doors

A window affects both heat transfer and solar gain.

Those effects can have different consequences depending on the local climate.

Why U-Factor Matters Differently Across Climates

U-factor describes thermal performance associated with a window or glazed assembly.

The significance of heat moving through a window depends partly on the temperature conditions outside the building.

That means the role of window thermal performance cannot be separated completely from climate.

The selected product should match the values used in the Title 24 documentation for the actual project location.

Why Solar Heat Gain Matters Differently Across Climates

Solar heat entering through glazing can increase cooling loads.

In some conditions, controlling solar heat gain can become particularly important.

The effect depends on factors including:

• Climate zone
• Window orientation
• Amount of glazing
• Building design

This is why the Energy Code evaluates window performance in the context of the actual building rather than using one generic statewide window assumption.

Roof Requirements Can Be Affected by Climate

Roofs receive significant exposure to outdoor conditions and solar radiation.

Depending on the project and applicable requirements, Title 24 may evaluate:

• Roof insulation
• Ceiling insulation
• Attic configuration
• Roofing characteristics
• Cool-roof characteristics when applicable

The value of particular roof strategies can differ by climate.

This is another reason project specifications should be based on the correct climate zone.

HVAC Requirements Interact With Climate Zone

Heating and cooling systems respond directly to outdoor conditions.

Climate can influence:

• Heating demand
• Cooling demand
• Equipment operation
• Building loads
• The relative benefit of efficiency measures

The HVAC system represented in the energy analysis should therefore correspond to the actual building, design, and climate conditions.

Climate Does Not Determine HVAC Requirements by Itself

Climate zone is important, but it is not the only variable.

Mechanical energy use can also depend on:

• Building size
• Orientation
• Insulation
• Window area
• Window performance
• Duct locations
• Ventilation
• Equipment efficiency

Two buildings in the same climate zone can therefore have very different energy performance.

Climate zone establishes environmental context; the building design determines how the project responds to it.

Duct Location Can Matter Differently Depending on Conditions

Ducts located outside conditioned space can be exposed to surrounding temperatures.

Depending on the mechanical design, ducts may pass through:

• Attics
• Crawlspaces
• Garages
• Other unconditioned areas

The energy effect of those conditions can differ depending on the climate and system configuration.

This is why the Title 24 report should represent the actual duct design rather than an assumption copied from another project.

Ventilation Requirements Must Work With Local Building Conditions

Energy efficiency and ventilation must operate together.

Modern buildings can be constructed with tighter envelopes, making controlled ventilation increasingly important.

The applicable ventilation requirements should be coordinated with:

• Building type
• Mechanical design
• Occupancy
• Applicable Energy Code provisions

Climate is part of the broader context within which those systems operate, even though not every ventilation requirement changes solely because of climate zone.

Climate Zones Help Avoid Overbuilding and Underbuilding

Climate-specific requirements help avoid two opposite problems.

The first is underbuilding energy performance for demanding conditions.

The second is imposing requirements that do not appropriately reflect local energy needs.

A climate-zone system allows California to tailor applicable standards so they better correspond to real building-energy conditions.

This supports a more rational compliance system than applying one identical prescriptive package across the entire state.

Climate Zones Create More Meaningful Energy Comparisons

A building’s energy performance should be compared against a reasonable reference.

If a desert building were evaluated using weather assumptions associated with a mild coastal area, its cooling performance could be misrepresented.

Likewise, using warm-climate assumptions for a building in a much colder region could underestimate heating conditions.

Climate zones help create a more appropriate baseline for energy calculations.

Climate Zone Is Especially Important in Performance Modeling

Performance-based Title 24 analysis evaluates multiple building characteristics together.

The model may consider relationships among:

• Building geometry
• Orientation
• Envelope characteristics
• Insulation
• Window area
• Window performance
• Roof characteristics
• HVAC equipment
• Duct conditions
• Water heating
• Other applicable systems

The applicable climate-zone conditions provide an environmental basis for that analysis.

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

Climate Zone Can Change Which Design Tradeoffs Work

Under a performance approach, energy measures can interact.

A design modification that helps significantly in one climate may produce a different benefit in another.

For example, the effect of changing:

• Window performance
• Glazing area
• Insulation
• Roof characteristics
• HVAC efficiency

depends on the complete project and local conditions.

This is why design recommendations should come from project-specific calculations rather than generic statements such as “add more insulation” or “buy better windows.”

Climate Zones Matter in Prescriptive Compliance Too

Performance modeling is not the only place climate matters.

Prescriptive requirements can also vary by climate zone.

A project using the prescriptive approach needs to satisfy the applicable component requirements for its specific climate zone and building type.

That can affect the specifications placed on the plans.

California Climate Zones Are Building-Energy Zones

The climate-zone system used for Title 24 is specifically intended to support California’s Building Energy Efficiency Standards.

It should not automatically be confused with:

• USDA planting zones
• Weather forecast regions
• County boundaries
• ZIP code boundaries
• Other climate-classification systems

The California Energy Commission defines geographic climate regions for Energy Code purposes.

A project’s building climate zone should therefore be confirmed using an appropriate official source.

A ZIP Code Does Not Always Tell the Whole Story

Some ZIP codes can contain more than one building climate zone.

The California Energy Commission therefore provides geographic tools for determining the applicable zone.

Local jurisdictions may also have procedures for climate-zone assignment in certain situations.

For a project near a climate-zone boundary, do not guess based only on the city name or ZIP code.

Verify the location before finalizing the energy analysis.

Does Climate Zone Change Every Title 24 Requirement?

No.

Climate zone is important, but it does not mean every Title 24 provision changes from one zone to another.

The Energy Code contains:

• Mandatory requirements
• Prescriptive requirements
• Performance requirements
• Building-type-specific requirements
• System-specific requirements

Some provisions apply broadly.

Others vary by climate zone.

Others depend primarily on building type or project scope.

The complete code must be considered before deciding what applies to a specific project.

Does Climate Zone Change Whether Title 24 Applies?

Climate zone generally affects how applicable energy requirements are determined rather than deciding whether California’s Energy Code exists in that location.

The Energy Code applies statewide to covered project types.

Climate zone helps establish the appropriate requirements and performance targets once the project is within the scope of the code.

Does Climate Zone Change the Type of Title 24 Report?

The overall type of compliance documentation depends mainly on:

• Building classification
• Project scope
• Compliance method
• Systems involved

Climate zone then affects applicable requirements or calculation assumptions within that process.

A single-family home and commercial restaurant in the same climate zone will not automatically use the same forms or calculations.

Likewise, two similar homes in different climate zones may have different energy requirements.

Why Climate Zone Matters for New Homes

A new home can be affected by climate-zone-specific requirements involving:

• Building envelope
• Windows
• Roof characteristics
• Heating and cooling
• Other applicable measures

Because the entire building is being designed at once, early identification of the climate zone can help avoid later plan changes.

Why Climate Zone Matters for ADUs

ADUs are often compact buildings, but they are still affected by local climate conditions.

A detached ADU may have:

• Four exposed exterior walls
• A complete roof assembly
• Windows on several elevations
• An independent HVAC system
• Its own water-heating system

Those characteristics interact with climate just as they do in a larger residential building.

For additional information, review the ADU Title 24 page.

Why Climate Zone Matters for Additions

An addition creates new building-envelope area exposed to local outdoor conditions.

Depending on the design, the project may add:

• Exterior walls
• Windows
• Roof area
• Conditioned floor area
• Heating and cooling loads

The climate zone helps establish the appropriate energy context for that new construction.

Why Climate Zone Matters for Commercial Buildings

Commercial buildings may have large:

• Glazing areas
• Mechanical systems
• Ventilation loads
• Roof areas
• Internal energy loads

Climate conditions interact with those systems.

Commercial energy calculations therefore need the correct location and climate-zone information just as residential calculations do.

For related professional services, review Title 24 compliance services and Title 24 energy analysis.

Why Climate Zone Matters for Multifamily Buildings

Multifamily projects can combine dwelling units, common areas, central systems, individual systems, and large building envelopes.

Climate zone can influence the applicable energy analysis for the building while the multifamily classification determines other parts of the compliance process.

The project must therefore be evaluated using both the correct building type and the correct climate zone.

Can Two Similar Buildings Have Different Title 24 Requirements?

Yes.

Two buildings with very similar:

• Floor area
• Architecture
• Window area
• HVAC systems

can still have different climate-sensitive requirements if they are located in different California building climate zones.

This does not mean one building is automatically less efficient.

It means the Energy Code is evaluating each project within its local environmental context.

Can the Same Window Be Acceptable in One Climate Zone and Not Another?

Potentially, depending on the project, compliance path, and applicable requirements.

Window performance is one of the areas the California Energy Commission identifies as climate-sensitive.

The correct determination depends on:

• Climate zone
• Building type
• Window area
• Orientation
• U-factor
• Solar heat gain coefficient
• Compliance method
• Other building features

Do not select windows solely from specifications used on another project.

Can the Same Insulation Package Work Everywhere?

Do not assume so.

The appropriate insulation requirements depend on the applicable code provisions, climate zone, building assemblies, and compliance method.

A wall or roof assembly used successfully in one project should not automatically be copied to a building in another climate zone without review.

Does Climate Zone Affect Title 24 Costs?

Climate zone can affect the building measures needed for compliance, but it is only one factor in overall project cost.

Costs may also depend on:

• Building size
• Architecture
• Window design
• Insulation choices
• HVAC systems
• Water heating
• Project complexity
• Selected compliance path

Likewise, the cost of the Title 24 consulting service itself depends on project scope, complexity, available documentation, revisions, and other project-specific factors.

What Happens if the Wrong Climate Zone Is Used?

Using the wrong climate zone can undermine the accuracy of an energy analysis.

Potential consequences can include:

• Incorrect performance assumptions
• Incorrect prescriptive requirements
• Window specifications that do not correspond to the project
• Envelope requirements that need correction
• Revised calculations
• Plan-check comments

The correct climate zone should be established before finalizing the compliance documents.

How Do I Find the Climate Zone for My Project?

Provide the project address when requesting Title 24 services.

The applicable climate zone can then be confirmed using California Energy Commission climate-zone resources and project information.

This is preferable to assuming that an entire county or ZIP code always belongs to one climate zone.

What Information Does AES Need in Addition to Climate Zone?

Climate zone is only one input.

AES may also need:

• Project address
• Floor plans
• Exterior elevations
• Building sections
• Roof plans
• Conditioned floor area
• Window schedules
• Window performance information
• Insulation details
• HVAC specifications
• Duct-location information
• Ventilation information
• Water-heating information
• Commercial lighting plans when applicable

Before sending plans, review what AES will need from you.

Climate Zone Is One Part of a Larger Energy Analysis

Climate zone is important, but it should never be treated as the only factor that determines Title 24 compliance.

The complete analysis can also depend on:

• Building type
• Construction scope
• Conditioned floor area
• Orientation
• Building geometry
• Insulation
• Windows
• Roof construction
• HVAC systems
• Ducts
• Ventilation
• Water heating
• Lighting
• Controls
• Compliance method

These factors interact.

Climate zone provides the environmental setting in which the rest of the building is evaluated.

Why Choose Alternative Energy Systems?

Alternative Energy Systems prepares Title 24 calculations and energy-compliance documentation for projects 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
• HVAC projects
• Commercial lighting projects
• Plan-check corrections
• Report revisions

AES reviews the actual project address, plans, building systems, and applicable climate zone so the energy documentation corresponds to the building being permitted.

Learn more through the About Us page or review company background on the clients page.

Get Title 24 Calculations for the Correct California Climate Zone

Call (626) 365-1518 | Alternative Energy Systems

Understanding Why Do Title 24 Standards Vary by Climate Zone starts with recognizing that California contains dramatically different building environments.

The state uses 16 building climate zones so applicable energy standards can reflect local conditions instead of assuming that every building experiences the same heating, cooling, solar, and envelope demands.

Climate zone can influence:

• Energy budgets
• Prescriptive requirements
• Building-envelope requirements
• Window requirements
• Roof characteristics
• Heating and cooling analysis
• Other climate-sensitive measures

Alternative Energy Systems can review the project address and plans, confirm the information needed for the analysis, and prepare the applicable Title 24 compliance documentation.

Call (626) 365-1518 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: Why Do Title 24 Standards Vary by Climate Zone?

Why Do Title 24 Standards Vary by Climate Zone?

California uses climate zones because buildings experience different heating, cooling, solar, and outdoor conditions throughout the state. Climate-specific requirements allow the Energy Code to reflect local building-energy conditions.

How many Title 24 climate zones are there in California?

California uses 16 building climate zones for Energy Code purposes.

Does every Title 24 requirement change by climate zone?

No. Some mandatory requirements apply broadly, while certain prescriptive requirements and performance energy budgets vary according to climate zone, building type, and project scope.

Why does climate affect building energy use?

Outdoor conditions influence heating and cooling loads, heat transfer through the envelope, solar gain through windows, and the operation of building systems.

Do window requirements vary by climate zone?

They can. The California Energy Commission specifically identifies fenestration requirements as one area that can depend on climate zone.

Does insulation vary by climate zone?

Applicable envelope requirements can be climate-sensitive, so the insulation assembly should be checked against the requirements for the project’s actual climate zone and compliance method.

Does roof performance vary by climate zone?

Applicable roof and envelope requirements can depend on climate and project conditions.

Does HVAC compliance vary by climate zone?

Climate affects heating and cooling loads, while applicable mechanical requirements also depend on building type, equipment, design, and compliance method.

Does climate zone affect a performance calculation?

Yes. Performance energy budgets vary by climate zone and building type.

Does climate zone affect prescriptive compliance?

Yes. Certain prescriptive measures can vary by climate zone.

Are California Title 24 climate zones the same as USDA planting zones?

No. California building climate zones are specifically used for Energy Code purposes.

Are climate zones based strictly on county boundaries?

No. Building climate-zone boundaries do not necessarily follow county or ZIP-code boundaries.

Can one ZIP code contain more than one climate zone?

Yes. The California Energy Commission notes that some ZIP codes can include more than one building climate region.

How do I determine the correct climate zone?

Use the California Energy Commission’s Building Climate Zone resources or provide the project address to the energy consultant for review.

Does climate zone determine whether Title 24 applies?

Climate zone generally affects which requirements or performance targets apply after the project falls within the Energy Code’s scope.

Can two identical houses have different Title 24 requirements?

Potentially. Similar buildings in different climate zones can have different climate-sensitive energy requirements.

Can I use a Title 24 report from a project in another climate zone?

No project-specific report should be reused automatically. The address, climate zone, building design, systems, plans, and compliance requirements all need to correspond to the actual project.

Does a mild climate mean Title 24 does not apply?

No. California’s Energy Code applies statewide to applicable project types. Climate zone affects the applicable requirements rather than eliminating the Energy Code.

Why are coastal and inland requirements different?

Coastal and inland buildings can experience different heating, cooling, and solar conditions, so climate-sensitive energy measures can have different effects.

Does climate zone matter for an ADU?

Yes. An ADU is evaluated using the climate zone applicable to its project location along with its building type, design, and systems.

Does climate zone matter for additions?

Yes. New conditioned space and new envelope assemblies are evaluated within the climate conditions applicable to the project location.

Does climate zone matter for commercial buildings?

Yes. Commercial energy calculations also use the applicable California building climate zone.

What if my project is near a climate-zone boundary?

Verify the project using official California Energy Commission climate-zone resources rather than relying solely on the city or ZIP code.

What happens if the wrong climate zone is used?

The analysis may use incorrect performance assumptions or requirements and can require correction or recalculation.

How can AES help?

Alternative Energy Systems can review the project address, plans, specifications, and applicable climate zone and prepare the appropriate Title 24 energy-compliance documentation.

How do I get started?

Call Alternative Energy Systems at (626) 365-1518 and provide the project address and current plans for review.

What Buildings Are Covered Under Title 24?

Call (626) 365-1518 | Alternative Energy Systems

What Buildings Are Covered Under Title 24 is an important question for anyone planning new construction, an addition, an ADU, a remodel, a commercial tenant improvement, or another California permit project that affects energy-related building components.

California’s Building Energy Efficiency Standards apply broadly to residential and nonresidential construction. Under the current Energy Code, applicable requirements can affect newly constructed buildings as well as additions and alterations to existing buildings.

That means Title 24 energy requirements can apply to projects involving:

• Single-family homes
• Duplexes
• Townhouses
• Accessory dwelling units
• Multifamily buildings
• Apartment projects
• Mixed-use buildings
• Office buildings
• Retail spaces
• Restaurants
• Warehouses
• Commercial tenant improvements
• Other nonresidential buildings

Coverage is not determined only by what the building is called.

The project scope also matters.

An existing building does not automatically need to be completely upgraded every time the Energy Code changes. Instead, applicable Title 24 requirements generally become relevant when a project involves new construction, an addition, an alteration, or another covered scope involving regulated building components or systems.

Alternative Energy Systems brings more than 30 years of California energy-compliance experience to residential, multifamily, mixed-use, and commercial projects.

Call (626) 365-1518 if you need to determine what energy documentation applies to a specific California building project.

Title 24 Covers Both Residential and Nonresidential Buildings

California’s Energy Code is not limited to houses.

It establishes energy requirements for broad categories of residential and nonresidential buildings.

The applicable requirements can differ significantly depending on whether the project is classified as:

• Single-family residential
• Multifamily
• Nonresidential

Each category can involve different:

• Compliance sections
• Forms
• Calculation methods
• Mechanical requirements
• Lighting requirements
• Verification requirements

That is why a Title 24 report for a house should not be treated as interchangeable with energy documentation for an apartment building, office, restaurant, warehouse, or retail tenant improvement.

Newly Constructed Buildings Are a Major Part of Title 24 Coverage

Newly constructed residential and nonresidential buildings are generally subject to the applicable California Energy Code requirements.

A new building provides the project team with an opportunity to coordinate energy requirements from the beginning.

The analysis may address:

• Building orientation
• Conditioned floor area
• Exterior walls
• Roof and ceiling assemblies
• Floors
• Windows
• Exterior doors
• Insulation
• HVAC equipment
• Duct systems
• Ventilation
• Water heating
• Lighting
• Lighting controls
• Other applicable energy systems

The exact analysis depends on the building type and selected compliance path.

Single-Family Homes Are Covered

New single-family homes are a primary residential category under California’s Energy Code.

Energy compliance can involve the home’s:

• Size
• Orientation
• Building envelope
• Window area
• Window performance
• Insulation
• Roof characteristics
• Heating and cooling systems
• Duct locations
• Ventilation
• Water heating
• Applicable lighting measures

These elements work together.

A project with large amounts of glazing, for example, may have different energy-performance characteristics from another home of similar size with much less glazing.

For more information about the analysis itself, review Title 24 energy calculations.

Duplexes and Townhouses Can Be Covered

California’s single-family residential Energy Code requirements can also apply to housing types such as duplexes and townhouses when they fall within the applicable single-family building classification.

These projects can involve many of the same energy considerations as a detached house, including:

• Envelope assemblies
• Insulation
• Windows
• Mechanical equipment
• Ventilation
• Water heating

However, the actual building configuration still matters.

Shared walls, attached units, conditioned spaces, and project-specific construction details should be represented correctly in the energy documentation.

Accessory Dwelling Units Can Be Covered

ADUs are common California projects that can require Title 24 energy-compliance review.

The requirements can depend on whether the ADU is:

• New detached construction
• Attached to an existing residence
• A garage conversion
• A conversion of another existing space

A newly constructed detached ADU may be evaluated as its own residential structure.

An attached ADU or conversion may require careful identification of existing and proposed construction.

Energy-related information can include:

• Conditioned floor area
• Wall construction
• Roof assemblies
• Insulation
• Windows
• HVAC
• Ventilation
• Water heating

Visit the ADU Title 24 page for additional project-specific information.

Garage Conversions Can Fall Under Title 24

A garage may begin as unconditioned space.

When that garage is converted into conditioned living space, the energy characteristics of the building change substantially.

The conversion can introduce requirements involving:

• Wall insulation
• Ceiling or roof insulation
• Floor conditions
• Windows
• Exterior doors
• Heating and cooling
• Ventilation
• Water heating
• Lighting

The fact that the exterior footprint already existed does not automatically mean the conversion falls outside energy requirements.

The relevant question is what construction work is being performed and how the space will be used after the project is complete.

Residential Additions Can Be Covered

Adding conditioned floor area to an existing home can trigger applicable Energy Code requirements.

Examples include:

• Bedroom additions
• Family-room additions
• Kitchen expansions
• Second-story additions
• Primary-suite additions
• Expanded living areas

The energy analysis may need to consider:

• New conditioned floor area
• New exterior walls
• New roof or ceiling assemblies
• New windows
• Insulation
• New or extended HVAC systems
• Ductwork
• Ventilation
• Water heating when affected

Not every addition necessarily requires the same compliance method.

Some projects may qualify for applicable prescriptive approaches, while others may use performance-based analysis.

Residential Remodels Can Be Covered When Regulated Components Change

A remodel does not need to add floor area before Energy Code requirements can become relevant.

An alteration may affect:

• Windows
• Exterior doors
• Exterior walls
• Insulation
• Roofing
• HVAC equipment
• Duct systems
• Ventilation
• Water-heating equipment
• Applicable lighting

A purely cosmetic project can be different from a remodel that changes regulated building components.

Describe the complete scope rather than assuming all remodels receive the same Title 24 treatment.

Multifamily Buildings Are Covered

California has dedicated Energy Code guidance for multifamily construction.

Multifamily projects can include:

• New apartment buildings
• Multifamily additions
• Alterations to apartment buildings
• Common-area improvements
• Other multifamily residential work

Multifamily energy compliance can involve both residential living areas and building systems serving multiple units or common spaces.

Depending on the project, the documentation may address:

• Building envelope
• Windows
• Mechanical systems
• Ventilation
• Water heating
• Lighting
• Other applicable systems

Multifamily projects should not automatically be analyzed using assumptions taken from a detached single-family home.

Apartment Renovations Can Trigger Energy Requirements

An existing apartment building is not automatically required to be rebuilt simply because a new Energy Code becomes effective.

However, alterations to the building can trigger applicable requirements.

Examples may include:

• Window replacement
• HVAC changes
• Water-heating changes
• Envelope improvements
• Common-area lighting changes
• Other regulated alterations

The applicable scope should be identified before deciding which compliance documents are needed.

Mixed-Use Buildings Can Be Covered

Mixed-use projects combine different occupancy or use types within the same development.

A project might include:

• Residential units above retail
• Apartments above restaurant space
• Residential and office areas
• Commercial spaces beneath multifamily housing

These projects can require careful energy coordination because different portions of the building may be subject to different applicable requirements.

The architectural, mechanical, electrical, lighting, and energy documentation should identify which requirements correspond to the various areas of the project.

Nonresidential Buildings Are Covered

California’s Energy Code applies broadly to applicable nonresidential new construction, additions, and alterations.

Nonresidential projects can involve more extensive system-specific requirements than a typical residential project.

The analysis may involve:

• Building envelope
• Mechanical systems
• Ventilation
• Service water heating
• Indoor lighting
• Outdoor lighting
• Sign lighting
• Electrical power distribution
• Applicable solar and battery provisions
• Covered processes
• Commissioning
• Acceptance testing

Which sections apply depends on the building and project scope.

For related services, review Title 24 compliance services and Title 24 energy analysis.

Office Buildings Can Be Covered

Office projects may require Title 24 documentation for new construction or applicable alterations.

Energy-related requirements may involve:

• Exterior walls and windows
• HVAC equipment
• Ventilation
• Interior lighting
• Lighting controls
• Water heating
• Other applicable electrical or mechanical features

An office tenant improvement can trigger energy requirements even when the exterior building remains largely unchanged.

The interior project may alter lighting, controls, HVAC, ventilation, or other regulated systems.

Retail Buildings and Stores Can Be Covered

Retail construction can involve Energy Code requirements for:

• Building-envelope components
• Storefront glazing
• Mechanical systems
• Ventilation
• Interior lighting
• Display lighting
• Lighting controls
• Exterior lighting when applicable

A retail tenant improvement should be evaluated according to the actual scope rather than assuming the existing building’s prior Title 24 documents cover the new work.

Restaurants Can Be Covered

Restaurant projects can involve several energy-related building systems.

Depending on the project, the compliance package may address:

• Building envelope
• HVAC systems
• Ventilation
• Water heating
• Lighting
• Lighting controls
• Applicable covered processes
• Other project-specific systems

Restaurant tenant improvements can be technically complex because architectural, mechanical, plumbing, electrical, and energy requirements often overlap.

Early coordination can help reduce conflicting project documents.

Warehouses Can Be Covered

Warehouse projects may also fall under nonresidential Energy Code requirements.

The exact scope can vary substantially depending on whether the building is:

• Conditioned
• Partially conditioned
• Unconditioned
• Used primarily for storage
• Combined with offices or other occupied areas

Even where some building-envelope or space-conditioning requirements differ, other regulated systems may still be relevant.

For example, lighting and other energy-related systems may require compliance depending on the project.

An unconditioned classification should therefore not automatically be treated as an exemption from every Energy Code provision.

Industrial Buildings Can Have Applicable Title 24 Requirements

Industrial projects can contain a mixture of:

• Office space
• Conditioned production space
• Warehousing
• Mechanical systems
• Lighting
• Process equipment

The Energy Code contains provisions for covered processes in addition to ordinary building systems.

That means industrial energy compliance can be highly project-specific.

The applicable scope should be determined from the actual building use and systems rather than from the word “industrial” alone.

Schools and Educational Buildings Can Be Subject to Energy Requirements

Educational facilities can involve nonresidential energy requirements related to their applicable building systems.

Depending on the project, these can involve:

• Building envelope
• Mechanical systems
• Ventilation
• Lighting
• Lighting controls
• Water heating

Certain specialized building types or project circumstances can have unique regulatory treatment, so educational projects should be reviewed according to their exact jurisdiction, project scope, and applicable code provisions.

Hotels and Motels Can Have Title 24 Requirements

Hotel and motel projects can involve extensive energy-compliance considerations because they combine sleeping accommodations with common areas and commercial building systems.

Applicable requirements may involve:

• Envelope performance
• Guest-room systems
• Mechanical equipment
• Ventilation
• Water heating
• Lighting
• Controls
• Common areas

The correct compliance approach depends on the actual building classification and project scope.

Commercial Tenant Improvements Can Be Covered Even When the Building Already Exists

A common misconception is that Title 24 applies only when the entire building is new.

Commercial tenant improvements can trigger requirements because they may alter regulated systems within an existing building.

Examples include:

• Office remodels
• Retail build-outs
• Restaurant improvements
• Medical office improvements
• Service-business spaces
• Warehouse office improvements
• Other commercial interior projects

The work may involve:

• New lighting
• Lighting controls
• Mechanical equipment
• Ventilation
• Water heating
• Storefront or envelope changes

The fact that the shell building is old does not automatically remove the new work from applicable Energy Code requirements.

Existing Buildings Are Covered When Applicable Additions or Alterations Are Made

Title 24 does not mean every existing California building must immediately be reconstructed to current standards.

Instead, requirements can apply when an existing building undergoes covered new construction.

This can include:

• Additions
• Alterations
• Replacement of regulated components
• Changes to building systems
• Conversions of space

The applicable provisions generally focus on the work being performed.

The exact requirements depend on the component, system, occupancy, and scope.

Changing the Occupancy or Use of a Space Can Affect Compliance

Changing how a building or portion of a building is used can affect which requirements apply.

For example, converting:

• A garage into living space
• A warehouse area into offices
• A commercial space into another occupancy
• Unconditioned space into conditioned space

can change the energy characteristics and regulatory treatment of the project.

The new use should be considered when determining the applicable compliance requirements.

Unconditioned Buildings Are Not Automatically Outside Title 24

Conditioned space receives considerable attention in energy calculations, but an unconditioned building should not automatically be assumed exempt from every requirement.

Depending on the project, regulated features may include:

• Lighting
• Outdoor lighting
• Sign lighting
• Electrical systems
• Covered processes
• Other applicable systems

The correct analysis depends on what is actually being constructed or altered.

Does Every Covered Building Need a Full Title 24 Energy Model?

No.

This is an important distinction.

A building can be subject to Energy Code requirements without requiring the same type of whole-building performance report used for another project.

Depending on the work, compliance may involve:

• Mandatory requirements
• Prescriptive compliance
• Performance-based compliance
• Alteration-specific forms
• Mechanical documentation
• Lighting documentation
• Installation forms
• Verification documents
• Acceptance-testing documents

A limited alteration should not automatically be treated like a completely new building.

Likewise, “no full energy model required” does not mean “no Title 24 requirements.”

Do All Repairs Trigger Title 24?

Not necessarily.

California distinguishes among new construction, additions, alterations, and repairs.

A true repair can be treated differently from an alteration.

However, simply calling work a “repair” does not automatically remove it from Energy Code requirements.

Replacing a regulated component can sometimes fall under alteration requirements.

Projects involving items such as:

• Windows
• Roofing
• HVAC equipment
• Ducts
• Water heating
• Lighting

should be evaluated according to the applicable scope before an exemption is assumed.

Are There Exceptions and Special Building Types?

Yes.

California’s Energy Code contains exceptions, special provisions, and different requirements for particular building types, occupancies, systems, and project scopes.

Not every section applies identically to every project.

Special circumstances can involve:

• Specific occupancy classifications
• Specialized facilities
• Certain repairs
• Particular alteration conditions
• Covered processes
• Unconditioned spaces
• Other code-defined exceptions

For that reason, a generalized list of building types should not be used as the sole basis for declaring that a project is either exempt or fully subject to every Energy Code provision.

The actual plans and scope should be reviewed.

Building Type Determines Which Compliance Manual and Requirements Apply

California provides separate compliance guidance for major building categories.

These include:

• Single-family residential
• Multifamily
• Nonresidential

The correct category affects:

• Applicable code sections
• Forms
• Prescriptive requirements
• Performance calculations
• Verification procedures
• Acceptance-testing requirements

Correct classification is therefore an important early step in preparing Title 24 documentation.

Climate Zone Also Matters After the Building Type Is Identified

California has 16 building climate zones.

Once the building and project scope are identified, climate zone can influence energy requirements involving areas such as:

• Envelope performance
• Windows
• Heating
• Cooling
• Roof characteristics
• Other climate-sensitive measures

The same building design can therefore have different energy considerations in different parts of California.

What Energy Features Are Reviewed in Covered Buildings?

Depending on the building and scope, AES may review:

• Conditioned floor area
• Building orientation
• Exterior wall assemblies
• Roof assemblies
• Ceiling assemblies
• Floor assemblies
• Insulation values
• Windows
• Exterior glazed doors
• Roof characteristics
• HVAC systems
• Duct locations
• Ventilation
• Water heating
• Residential lighting
• Commercial lighting
• Lighting controls
• Other applicable regulated systems

For more information about these factors, review Title 24 energy compliance.

What Plans Should You Send to Determine Coverage?

If you are unsure what requirements apply, provide AES with the current project information.

Helpful documents can include:

• Floor plans
• Existing and proposed plans
• Exterior elevations
• Building sections
• Roof plans
• Window schedules
• Insulation details
• HVAC information
• Duct information
• Ventilation information
• Water-heating specifications
• Commercial lighting plans
• Commercial lighting-control plans
• Existing Title 24 documentation
• Building-department correction comments

Not every project requires every document.

AES can review the available information and identify what else is needed.

Before submitting files, review what AES will need from you.

Why Early Building Classification Matters

Misunderstanding the building type or project scope can cause problems later.

Potential issues include:

• Using the wrong compliance forms
• Applying the wrong assumptions
• Leaving required systems out of the analysis
• Using residential assumptions for a nonresidential project
• Failing to identify an addition correctly
• Failing to distinguish existing and proposed construction

Early review helps the energy documentation reflect the actual project from the beginning.

Why the Report Must Match the Covered Building

A Title 24 report is project-specific.

It should not be copied from another building simply because the projects appear similar.

The report should reflect the actual:

• Address
• Building type
• Occupancy
• Project scope
• Floor area
• Envelope
• Windows
• Mechanical systems
• Water heating
• Lighting when applicable

Using energy documentation prepared for a different project can create discrepancies during plan review.

What Happens if the Building Type Changes During Design?

A major change in use or occupancy can affect the compliance approach.

Notify AES if a project changes from one use to another or if the scope changes significantly.

Provide:

• The revised plans
• The revised project description
• Updated mechanical information
• Updated lighting information when applicable
• Updated water-heating information

The existing calculations and forms can then be reviewed to determine what needs to change.

What if the Building Department Says Title 24 Is Required?

If a plan reviewer requests energy documentation, provide AES with:

• The complete correction notice
• The current plans
• The project description
• Any previously submitted energy forms
• Current equipment specifications

AES can review whether the project needs:

• A complete energy report
• Limited calculations
• Applicable prescriptive forms
• A revision to an existing report
• Clarification or plan coordination

The complete correction notice provides better context than one isolated comment.

What California Energy Code Is Currently Used?

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

The current standards apply to residential and nonresidential newly constructed buildings, additions, and alterations according to the applicable provisions.

For official statewide information, review the California Energy Commission 2025 Building Energy Efficiency Standards.

Why Choose Alternative Energy Systems?

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

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

• Single-family homes
• ADUs
• Garage conversions
• Additions
• Residential remodels
• Multifamily buildings
• Mixed-use projects
• Commercial buildings
• Office tenant improvements
• Retail projects
• Restaurant improvements
• Warehouse alterations
• HVAC projects
• Commercial lighting projects
• Plan-check corrections

AES reviews the actual building and project scope before determining what information is needed for the energy-compliance package.

Learn more through the About Us page or review company background on the clients page.

Find Out Whether Your Building Project Requires Title 24 Documentation

Call (626) 365-1518 | Alternative Energy Systems

Understanding What Buildings Are Covered Under Title 24 starts with two questions:

• What type of building is involved?
• What construction work is being performed?

California’s Energy Code broadly covers applicable residential and nonresidential newly constructed buildings, additions, and alterations.

However, the specific requirements can vary according to building classification, occupancy, climate zone, existing conditions, project scope, systems being changed, and the selected compliance method.

Alternative Energy Systems can review your project and help determine which energy-compliance service is appropriate.

Call (626) 365-1518 to:

• Describe the building type
• Explain the proposed construction
• Submit current plans
• Determine what project information is needed
• Request Title 24 calculations
• Request applicable compliance documentation
• Review an existing report
• Address energy-related plan-check corrections

You may also 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: What Buildings Are Covered Under Title 24?

What Buildings Are Covered Under Title 24?

California’s Energy Code applies broadly to residential and nonresidential newly constructed buildings, additions, and alterations. The specific requirements depend on building classification, project scope, systems involved, and applicable exceptions.

Are single-family homes covered?

Yes. Newly constructed single-family homes and applicable additions and alterations are subject to the relevant residential Energy Code requirements.

Are duplexes covered?

Duplexes can fall within the applicable single-family residential Energy Code category.

Are townhouses covered?

Townhouses can be subject to applicable single-family residential Energy Code requirements depending on the building configuration and project scope.

Are ADUs covered?

Yes. New detached ADUs, attached ADUs, garage conversions, and other ADU configurations can require applicable Title 24 energy compliance.

Are garage conversions covered?

Garage conversions can trigger Energy Code requirements because previously unconditioned space may become conditioned living space.

Are home additions covered?

Yes. Additions to existing residential buildings can be subject to applicable Energy Code requirements.

Are residential remodels covered?

They can be. Alterations affecting regulated components such as windows, insulation, roofing, HVAC, ducts, ventilation, water heating, or lighting can trigger applicable requirements.

Are apartment buildings covered?

Yes. California provides dedicated multifamily Energy Code requirements and compliance guidance.

Are multifamily renovations covered?

Applicable additions and alterations to multifamily buildings can be subject to Energy Code requirements.

Are mixed-use buildings covered?

Yes. Mixed-use projects can involve different requirements for residential and nonresidential portions of the building.

Are office buildings covered?

Yes. New office buildings and applicable office additions and alterations can be subject to nonresidential Energy Code requirements.

Are retail stores covered?

Yes. Retail buildings and tenant improvements can involve Title 24 requirements for envelope components, mechanical systems, lighting, controls, and other regulated systems.

Are restaurants covered?

Yes. Restaurant projects can involve nonresidential energy requirements for mechanical systems, ventilation, lighting, water heating, building envelope, and applicable covered processes.

Are warehouses covered?

Warehouses can be subject to applicable Energy Code provisions. Requirements depend on whether areas are conditioned, unconditioned, mixed with offices, and what systems are included.

Are industrial buildings covered?

Applicable industrial buildings can be subject to nonresidential Energy Code provisions, including requirements involving ordinary building systems and certain covered processes.

Are schools covered?

Educational buildings can be subject to applicable Energy Code requirements, although specialized facilities and project circumstances may have additional or different provisions.

Are hotels and motels covered?

Hotel and motel construction can be subject to applicable Energy Code requirements involving envelope, mechanical systems, ventilation, water heating, lighting, controls, and other regulated systems.

Are commercial tenant improvements covered?

Yes. A tenant improvement can trigger applicable requirements even though the overall building already exists.

Are existing buildings covered?

Existing buildings are not automatically required to be completely upgraded simply because a new Energy Code takes effect. Applicable requirements generally arise when covered additions, alterations, or other regulated work are performed.

Are unconditioned buildings exempt?

Not automatically. Some requirements may differ, but lighting, electrical systems, covered processes, or other regulated features can still be applicable depending on the project.

Does every covered building need a full energy model?

No. Some projects use prescriptive compliance or limited project-specific forms rather than a complete whole-building performance analysis.

Do minor repairs require a Title 24 report?

Not every repair does. California distinguishes repairs from alterations, but replacement of certain regulated components may trigger applicable alteration requirements.

Does changing a building’s use affect Title 24?

It can. A change in occupancy, use, or conditioned-space status can affect which Energy Code provisions apply.

Does every covered building use the same forms?

No. Forms and calculations differ among single-family, multifamily, nonresidential, new construction, additions, alterations, and specific building systems.

How do I find out what applies to my building?

Call Alternative Energy Systems at (626) 365-1518 and provide the building type, proposed work, and current plans for review.