Why Are Title 24 Standards Updated Every Three Years?

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Why Are Title 24 Standards Updated Every Three Years comes down to a practical problem: buildings last for decades, but construction technology, energy systems, equipment efficiency, electrical demand, building science, and California’s broader energy needs continue to change.

California uses a three-year building-code cycle so its Building Energy Efficiency Standards can be reviewed and updated regularly rather than remaining frozen while technology and construction practices move forward.

The cycle gives the California Energy Commission and California Building Standards Commission time to:

• Evaluate how the current standards are working
• Review new building technologies
• Study changes in energy use
• Evaluate building and equipment performance
• Consider grid conditions and electricity demand
• Review new model building codes
• Develop proposed regulatory changes
• Conduct workshops and public hearings
• Receive comments from industry and the public
• Prepare compliance manuals, forms, and supporting materials
• Give designers, builders, consultants, and building departments time to prepare for the new code

The result is a repeating process that allows California to improve energy standards without rewriting the building code every year.

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 which Energy Code cycle applies to your project or need Title 24 calculations prepared for current plans.

The Three-Year Cycle Is Part of California’s Building-Code System

California’s Building Energy Efficiency Standards are part of Title 24 of the California Code of Regulations.

The Energy Code is primarily contained in Title 24, Part 6, with related administrative requirements in Part 1.

California’s broader Building Standards Code also operates through a triennial code-adoption cycle.

That provides a regular schedule for state agencies to review building requirements and coordinate them with updated model codes and California-specific amendments.

The three-year cycle creates a balance.

Updating too slowly could leave requirements based on outdated technology.

Updating the complete code every year could make planning, permitting, training, software development, product selection, and enforcement unnecessarily difficult.

A three-year cycle provides a predictable period for substantial updates while still allowing the standards to evolve regularly.

Why Not Keep the Same Title 24 Standards for Ten or Twenty Years?

Building technology changes too quickly for an energy code to remain unchanged for decades.

Consider how rapidly the construction industry can change in areas such as:

• Heat pumps
• Water-heating technology
• Window performance
• Insulation products
• HVAC efficiency
• Ventilation equipment
• Lighting technology
• Lighting controls
• Solar systems
• Battery storage
• Building controls
• Demand-responsive equipment

A requirement that was technically ambitious during one code cycle may become standard construction practice several years later.

At the same time, new systems may create compliance questions that earlier editions never needed to address.

Regular updates allow the Energy Code to respond to those changes.

New Building Technology Is One Reason Standards Need Regular Updates

Building systems do not stand still.

Manufacturers continually develop:

• More efficient HVAC equipment
• Improved heat pumps
• Better-performing windows
• More efficient water-heating systems
• Advanced lighting controls
• Improved ventilation equipment
• Solar and battery technologies
• Building-management and demand-control systems

When technologies become practical, available, and cost-effective, California can evaluate whether they should influence future minimum requirements or compliance options.

Without periodic updates, the code could continue treating older technology as the normal baseline long after the market has moved forward.

Energy-Efficiency Improvements Change What Is Reasonable to Require

Energy standards must consider what can realistically be built.

A product or system that is rare, extremely expensive, or experimental should not automatically become a statewide minimum requirement.

Over time, however, technologies can become:

• More widely available
• More reliable
• Less expensive
• Easier to install
• Better understood by contractors
• Supported by stronger manufacturer networks

The three-year cycle gives regulators an opportunity to evaluate whether construction practices have changed enough to justify updated standards.

The Energy Code Is Updated to Reduce Wasteful Energy Use

The California Energy Commission is required to develop building-efficiency standards intended to reduce wasteful, uneconomical, inefficient, or unnecessary energy consumption.

That means each code cycle can examine where additional practical energy savings may be available.

Areas considered can involve:

• Building envelopes
• Windows and glazing
• Roofs
• HVAC systems
• Duct systems
• Ventilation
• Water heating
• Lighting
• Lighting controls
• Other regulated building systems

The purpose is not simply to make each new edition longer.

Changes are intended to respond to evolving opportunities for improving building performance.

Building Energy Use Changes as California Changes

California’s buildings collectively represent a major portion of statewide electricity use.

That means the way new homes, apartments, offices, stores, restaurants, warehouses, and other buildings are designed can affect the larger energy system.

Regular updates allow the state to evaluate:

• Building energy demand
• Electricity-use patterns
• Peak-demand periods
• Changing equipment technologies
• How buildings interact with the electrical grid

Energy efficiency is therefore both a building-level issue and a statewide infrastructure issue.

The Electrical Grid Is Another Reason the Standards Evolve

Modern energy policy is not concerned only with how much electricity a building uses over an entire year.

When energy is used can also matter.

Periods of high statewide electricity demand can place greater pressure on the grid.

Newer code cycles can therefore evaluate strategies involving:

• Efficient heat pumps
• Electric-ready construction
• Solar energy
• Battery storage
• Demand flexibility
• Controls that can help shift energy use

The 2025 Energy Code places additional emphasis on efficient electric technologies and strategies that can help move electricity consumption away from periods of peak demand.

A repeating code cycle gives California a mechanism for incorporating these changing grid needs into future building standards.

Greenhouse-Gas Goals Influence Energy-Code Development

Building energy consumption is also connected to greenhouse-gas emissions.

As California’s electricity and building systems evolve, the state can reassess which building strategies offer practical reductions in emissions.

This can involve:

• Building efficiency
• Space-conditioning technology
• Water heating
• Electrical equipment
• Solar generation
• Battery storage
• Demand-responsive technologies

The three-year cycle allows those issues to be reconsidered as the energy system changes.

Indoor Air Quality and Ventilation Also Change With Building Science

Energy standards cannot focus only on reducing energy consumption.

Buildings also need appropriate ventilation and indoor environmental performance.

Construction has become more sophisticated and building envelopes can become tighter.

That increases the importance of coordinating energy efficiency with ventilation.

California’s Energy Code can therefore evolve as knowledge improves regarding:

• Whole-building ventilation
• Local exhaust
• Mechanical ventilation systems
• Indoor air quality
• Interaction between ventilation and HVAC equipment

The 2025 Energy Code includes strengthened ventilation requirements as part of the current standards.

Climate Conditions Remain Important During Every Update

California does not have one uniform climate.

The state uses 16 building climate zones for Energy Code purposes.

Those zones help account for differences in:

• Heating demand
• Cooling demand
• Solar conditions
• Building-envelope performance
• Mechanical-system loads

As the code is updated, requirements and compliance methods can continue to account for the different conditions found throughout California.

Cost-Effectiveness Is an Important Part of Energy-Code Updates

Energy standards are not developed solely by asking whether a technology saves energy.

The economic effect of proposed requirements is also important.

A possible code change may need to be evaluated in terms of:

• Initial construction cost
• Energy savings
• Equipment life
• Maintenance
• Long-term operating cost
• Availability of products
• Practical construction impacts

This is another reason updates require a structured rulemaking process rather than being changed informally whenever a new product appears.

The Three-Year Cycle Allows Time for Research

Before a new Energy Code becomes effective, technical work occurs behind the scenes.

The process may include:

• Research
• Engineering analysis
• Energy modeling
• Cost analysis
• Stakeholder workshops
• Draft regulatory language
• Public review
• Formal rulemaking

The three-year schedule provides time to evaluate proposed changes before they become enforceable requirements.

The Public Can Participate in the Update Process

Energy Code updates are not prepared through a closed process.

The California Energy Commission uses workshops, hearings, notices, rulemaking documents, and opportunities for public comment.

Participants may include:

• Architects
• Engineers
• Energy consultants
• Contractors
• Product manufacturers
• Utilities
• Building officials
• Industry organizations
• Researchers
• Members of the public

Input from these groups can help identify practical issues before proposed requirements become part of the final code.

Why Is Public Review Important?

A requirement may appear technically reasonable while creating unexpected construction or enforcement problems.

Public review can surface questions such as:

• Is the product widely available?
• Can contractors install it reliably?
• Can building departments enforce the requirement consistently?
• Are compliance forms clear?
• Is the requirement cost-effective?
• Will software be able to model the change?

This feedback can improve the final standards before they take effect.

The Three-Year Cycle Also Coordinates Title 24 With Model Building Codes

California’s Building Standards Code includes more than energy requirements.

Its triennial adoption process coordinates state standards with updated model codes used for building, plumbing, mechanical, electrical, and other areas of construction.

That helps maintain a structured relationship among the different parts of Title 24.

Energy requirements do not exist in isolation.

A project may involve:

• Architecture
• Structural engineering
• Mechanical design
• Electrical design
• Plumbing
• Energy compliance
• CALGreen requirements

Regular code cycles help those systems evolve within the broader California building-code framework.

What Happens During a Title 24 Update Cycle?

A new Energy Code does not appear overnight.

The process generally develops through several stages.

Research and Pre-Rulemaking

The California Energy Commission gathers information, analyzes possible changes, and conducts workshops.

Proposed Standards

Potential regulatory changes are developed and published for review.

Public Comment

Stakeholders have opportunities to review proposed requirements and provide feedback.

Formal Rulemaking

Proposed regulations move through the state’s formal adoption process.

Adoption

The California Energy Commission adopts the Energy Code, followed by the applicable building-standards approval process.

Preparation for Implementation

Before the effective date, supporting materials may include:

• Compliance manuals
• Reference appendices
• Forms
• Software
• Training materials

Effective Date

The new code then becomes applicable according to the established effective date and permit rules.

What Energy Code Is Currently in Effect?

As of 2026, the current statewide cycle is the 2025 California Energy Code.

For applicable buildings whose permit applications are filed on or after January 1, 2026, the 2025 Energy Code applies.

The 2025 update includes changes involving areas such as:

• Heat-pump technology
• Electric readiness
• Ventilation
• Building efficiency
• Demand-responsive energy use

Projects should be evaluated using the code cycle applicable to the permit application rather than assuming an older report remains current.

Why Is It Called the 2025 Energy Code if It Took Effect in 2026?

This naming convention can be confusing.

The edition is identified as the 2025 California Energy Code, but its statewide effective date is January 1, 2026.

This means:

• 2025 is the edition name
• January 1, 2026 is the effective date

The same type of distinction has occurred with previous editions.

For example:

• The 2019 standards took effect January 1, 2020
• The 2022 standards took effect January 1, 2023
• The 2025 standards took effect January 1, 2026

Understanding the edition and effective date helps prevent the wrong compliance documents from being used.

What Is the Next Title 24 Energy-Code Cycle?

California is already developing the 2028 Building Energy Efficiency Standards.

The California Energy Commission states that the updated standards are expected to be proposed for adoption in 2027 and take effect January 1, 2029.

The process includes workshops and public participation before the standards become final.

This illustrates why the update process is continuous.

While one edition is being enforced, work on the next edition can already be underway.

Does Every Requirement Change Every Three Years?

No.

A new code edition does not mean every previous requirement is discarded.

Some requirements may:

• Remain substantially unchanged
• Be clarified
• Be reorganized
• Become more stringent
• Change only for certain project types
• Be replaced by a different compliance approach

The effect on a particular project depends on the building type and scope.

That is why comparing only one individual requirement from two different code cycles can give an incomplete picture.

Can Title 24 Change Between the Major Three-Year Editions?

The major editions follow the triennial cycle, but that does not mean absolutely nothing can change between editions.

California’s building-standard system also allows supplements and other authorized rulemaking actions during an existing code edition.

These can include changes adopted through intervening code cycles or other authorized regulatory processes.

For most project teams, the practical approach is to confirm the currently applicable code and forms rather than relying on an old checklist saved from a previous job.

Why Do Compliance Forms Change?

When the Energy Code changes, the forms used to document compliance may also need to change.

Forms may be revised because:

• New requirements were introduced
• Existing requirements changed
• Terminology changed
• Verification procedures changed
• New technologies need to be documented
• The compliance process was reorganized

Using an outdated form can create confusion even if the project information itself is accurate.

AES prepares documentation according to the applicable project and current compliance requirements.

Why Does Compliance Software Need to Be Updated?

Performance-based energy calculations rely on approved compliance methods and software.

When the Energy Code changes, software may need to incorporate:

• New requirements
• New reference assumptions
• Different equipment characteristics
• Updated calculation procedures
• New compliance metrics

This is one reason there is a transition period between code development and the date when the new standards become enforceable.

Consultants and design teams need time to use the updated tools correctly.

Why Do Title 24 Consultants Need to Follow Each New Code Cycle?

A report prepared under an older code cycle may use:

• Older forms
• Older software
• Older compliance assumptions
• Different efficiency requirements
• Different verification requirements

Energy consultants therefore need to keep current with:

• Code updates
• Compliance manuals
• Forms
• Software
• Verification procedures

The project should be analyzed using the requirements applicable to its actual permit timing and scope.

What Does the Three-Year Cycle Mean for Architects and Designers?

Architects and designers should identify the anticipated permit timing early.

A project designed near the transition between code editions may need additional planning.

Important questions include:

• When is the permit application expected to be filed?
• Which Energy Code will apply?
• Will the design continue into the next code cycle?
• Are the current product assumptions appropriate for that cycle?
• Does the Title 24 report match the current plans?

Long design schedules make these questions particularly important.

What Does the Cycle Mean for Contractors?

Contractors should not assume that requirements from a previous project automatically apply to a new project.

A new permit may fall under a different Energy Code.

Before purchasing or substituting:

• Windows
• Insulation
• HVAC equipment
• Water-heating equipment
• Lighting
• Controls

compare the proposed product with the approved plans and current energy documentation.

What Does the Cycle Mean for Homeowners?

Homeowners may encounter different Title 24 requirements on projects completed only a few years apart.

For example, requirements associated with:

• ADUs
• Additions
• HVAC systems
• Water heating
• Windows
• Ventilation

can change as new code editions become effective.

Do not assume that a relative’s project from several years ago provides an exact compliance template for a project being permitted today.

What Does the Cycle Mean for Commercial Projects?

Commercial projects may have long design and construction schedules.

A project can involve:

• Envelope requirements
• Mechanical systems
• Ventilation
• Service water heating
• Interior lighting
• Exterior lighting
• Lighting controls

Because several disciplines may be involved, identifying the applicable code cycle early can help the architectural, mechanical, electrical, and energy documents remain coordinated.

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

Can an Old Title 24 Report Be Used Under a New Code Cycle?

Do not assume that an old report can simply be reused.

An earlier report may have been prepared using:

• A different Energy Code edition
• Different plans
• Different compliance software
• Older equipment specifications
• Older forms

The project itself may also have changed.

AES should receive:

• The existing report
• The current plan set
• The current project scope
• Updated specifications
• Available permit information

The documents can then be reviewed to determine what needs to be updated.

Does a New Code Cycle Automatically Change a Previously Issued Permit?

Do not assume a new edition automatically rewrites an existing permit.

The applicable code depends on the project’s permit circumstances and jurisdictional requirements.

A project that has already entered the permit process may be in a different situation from a new application filed after the effective date of the newer Energy Code.

When permit timing crosses a code transition, confirm the applicable requirements with the building department and project professionals rather than guessing.

Why Early Title 24 Review Matters Near a Code Change

Code transitions can create avoidable confusion when project documents are not coordinated.

Early review helps determine:

• Which code edition applies
• Which forms should be used
• Whether the available calculations are current
• Whether the project design changed
• Whether new requirements affect the plans

This can be particularly important for projects with extended architectural or engineering schedules.

How the Three-Year Cycle Helps Improve the Permit Process

Regular updates establish clear editions rather than an unpredictable stream of completely new requirements.

Each major edition can be accompanied by:

• Published standards
• Compliance manuals
• Reference appendices
• Compliance forms
• Software
• Training and guidance

Building departments and industry professionals can then prepare for implementation around an established effective date.

The Three-Year Cycle Does Not Mean Older Buildings Must Be Rebuilt Every Three Years

A new Energy Code edition does not mean every existing California building must immediately be reconstructed to the newest standards.

The Energy Code applies according to project type and scope.

It commonly becomes relevant when there is:

• New construction
• An addition
• An applicable alteration
• Another covered permit scope

Existing buildings can therefore continue to operate without being completely rebuilt every time a new code edition is published.

Why the Cycle Matters for ADUs, Additions, and Remodels

Smaller residential projects can be affected by changing code requirements just as new homes can.

That can include:

• Detached ADUs
• Attached ADUs
• Garage conversions
• Room additions
• Major remodels
• HVAC alterations

An ADU designed under assumptions from an older code edition should not automatically be treated as compliant with the current requirements.

Visit the ADU Title 24 page for additional information.

Why Choose Alternative Energy Systems?

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

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

• New residential construction
• New commercial construction
• ADUs and garage conversions
• Additions and remodels
• Multifamily projects
• Commercial tenant improvements
• HVAC projects
• Commercial lighting projects
• Plan-check corrections
• Revisions to existing reports and calculations

AES reviews the actual project scope, plans, systems, and applicable Energy Code requirements rather than assuming that documentation prepared under an earlier code edition remains suitable.

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

Make Sure Your Project Uses the Correct Title 24 Standards

Call (626) 365-1518 | Alternative Energy Systems

Understanding Why Are Title 24 Standards Updated Every Three Years helps explain why a Title 24 report prepared several years ago cannot automatically be reused for a current permit project.

The three-year cycle gives California a structured way to respond to:

• New building technology
• Improved energy efficiency
• Changing equipment
• Electrical-grid needs
• Greenhouse-gas reduction goals
• Ventilation and indoor air-quality research
• Cost-effectiveness
• Updated model building codes
• Industry and public feedback

Alternative Energy Systems can help determine which Energy Code applies to your project and prepare the appropriate energy-compliance documentation.

Call (626) 365-1518 to:

• Discuss the project scope
• Confirm the current plans
• Request Title 24 calculations
• Request a new energy report
• Review an older report
• Evaluate design changes
• Address plan-check corrections

You may also begin through the contact page.

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

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

For current statewide standards and code-cycle information, review the California Energy Commission Building Energy Efficiency Standards.

Frequently Asked Questions: Why Are Title 24 Standards Updated Every Three Years?

Why Are Title 24 Standards Updated Every Three Years?

California uses a three-year building-code cycle so the Energy Code can respond regularly to changes in building technology, efficiency, construction practices, energy demand, model codes, and statewide energy goals while maintaining a predictable implementation schedule.

Who updates California’s Energy Code?

The California Energy Commission develops and adopts the Building Energy Efficiency Standards through the applicable state rulemaking process. The standards become part of California’s Title 24 building-code system.

Is Title 24 updated every year?

The major editions follow a three-year adoption cycle. Other authorized supplements or regulatory changes can occur within an existing edition.

Why not update the entire code every year?

A three-year cycle provides time for technical research, economic analysis, public review, rulemaking, preparation of compliance tools, and industry training before substantial new requirements become effective.

Why does building technology require code updates?

HVAC systems, heat pumps, windows, water heating, controls, solar, battery storage, and other technologies continue to change. Regular updates allow standards to reflect technologies that have become practical and cost-effective.

Does energy efficiency improve between code cycles?

Technology and construction practices can improve over time, giving California opportunities to evaluate additional cost-effective energy savings during later code cycles.

Do grid conditions influence the Energy Code?

Yes. Current standards increasingly consider when buildings use electricity in addition to how much they use, including strategies intended to reduce demand during peak periods.

Do greenhouse-gas goals influence updates?

Yes. Building energy efficiency and energy-system choices can affect greenhouse-gas emissions and are among the considerations behind California’s Energy Code.

Does indoor air quality influence code updates?

Yes. Ventilation and indoor air quality are important building-performance issues, and current Energy Code requirements address ventilation alongside energy efficiency.

Are proposed changes reviewed publicly?

Yes. The California Energy Commission conducts workshops and formal rulemaking processes that provide opportunities for public and industry participation.

Does cost matter when standards are updated?

Yes. Proposed energy-efficiency measures are evaluated through technical and economic processes rather than simply being adopted because they use less energy.

What Energy Code is currently in effect?

For applicable permit applications filed on or after January 1, 2026, the 2025 California Energy Code is the current statewide edition.

Why is the 2025 Energy Code effective in 2026?

2025 is the edition name. Its statewide effective date is January 1, 2026.

What was the previous Energy Code?

The 2022 Energy Code took effect January 1, 2023 and preceded the current 2025 edition.

What is the next Energy Code?

California is developing the 2028 Building Energy Efficiency Standards, which are expected to be adopted through the upcoming process and take effect January 1, 2029.

Does every requirement change with each edition?

No. Some provisions remain similar, while others may be revised, clarified, reorganized, expanded, or replaced.

Can the code change between three-year editions?

Certain supplements and other authorized rulemaking actions can modify an existing edition, so project teams should verify current requirements rather than relying exclusively on old materials.

Do Title 24 forms change when the Energy Code changes?

They can. New code requirements, terminology, verification procedures, and compliance methods may require updated forms.

Does compliance software change?

Approved software and calculation procedures can be updated to reflect the requirements and assumptions of a new Energy Code.

Can I use a Title 24 report from the previous code cycle?

Do not assume an older report remains valid. The applicable code, current plans, report forms, specifications, and project changes should be reviewed.

Does a new code cycle mean existing buildings must be upgraded immediately?

No. Existing buildings are not automatically rebuilt each time a new edition is adopted. Energy Code requirements apply according to the scope of new construction, additions, alterations, and other applicable work.

Do ADUs follow current Energy Code requirements?

ADUs are evaluated according to the applicable project type, permit timing, and Energy Code requirements rather than automatically using the rules from an older project.

How do I know which Title 24 standards apply to my project?

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