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.