What Is Title 24?

Title 24 is the part of the California Code of Regulations that contains the state’s building standards. In construction, “Title 24” almost always means Part 6, the Building Energy Efficiency Standards: the energy rules a project is designed to, checked against before the permit is issued, and verified on site before final inspection.

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What the name actually refers to

California’s regulations are organised into numbered titles. Title 24 is the California Building Standards Code, and it is divided into parts covering different aspects of construction — structural, plumbing, electrical, fire and so on. Part 6 covers energy efficiency, and it is the part that generates the paperwork most projects are asked for at permit.

So a building department asking for “your Title 24” is asking for documentation showing the project meets the Part 6 energy standards. Part 11, the California Green Building Standards Code (CALGreen), is a separate part of the same code and is not the same requirement.

Why the standards change

The Energy Commission updates the standards on a three-year cycle. Each edition takes effect on a stated date, and projects are generally evaluated against the edition in force when the permit application is submitted — not when the work is finished. This matters on projects that sit between cycles, because a set of calculations prepared under one edition may not satisfy the next.

When a project needs a report

Requirements attach to the work being done rather than to the building type alone. New construction is covered. So are many additions and alterations, including work that changes the building envelope, replaces windows, or installs or alters heating, cooling or water-heating equipment. Some cosmetic work is not covered at all.

Because the trigger is the scope of work, two projects on identical houses can reach different answers. The reliable way to know is to check the specific scope against the current standards, which is what a compliance report does.

What the report contains

A residential report is normally a Certificate of Compliance in the CF1R family, produced in software the Energy Commission has approved for the current code cycle. It records the building geometry, envelope assemblies, glazing, and mechanical and water-heating systems, then demonstrates that the design complies — either by meeting each prescriptive requirement, or by showing through modelling that the whole building performs at least as well as a reference design.

Nonresidential projects use a different form family. Some measures also require third-party field verification, which is registered through an approved data registry rather than being certified on paper alone.

How Title 24 shows up in a construction project

On a building project, energy compliance is not one document handed in at the start. It runs alongside the job from design to sign-off, and each stage has its own paperwork:

Design. The designer, or an energy consultant working for them, checks the drawings against Part 6 for the project’s climate zone and chooses between the prescriptive and performance approaches.
Certificate of compliance. The result goes on the CF1R for a home or the NRCC forms for commercial work, signed by the documentation author who prepared it and by the person responsible for the design. Where a home relies on field verification, the certificate is registered with an ECC-Provider data registry before plan check.
Plan check. The building department compares the certificate with the drawings. It may not issue the permit until it has determined in writing, usually with its approval stamp, that the design meets the Part 6 edition in effect on the date the permit was applied for. For applications made on or after 1 January 2026, that is the 2025 Energy Code.
Construction. As each regulated item goes in, such as insulation, windows, heating and cooling or water heating, the person in charge of installing it completes a certificate of installation: the CF2R on residential work.
Field verification. Items that cannot be checked by eye, such as duct leakage or refrigerant charge, are tested by an independent ECC-Rater, the role called a HERS rater until 1 January 2026, who records the results on a CF3R. Commercial lighting controls and mechanical systems get acceptance tests instead, recorded on NRCA forms.
Final inspection. The inspector checks that what was built matches the approved plans and that the certificates are in place. No final certificate of occupancy is issued until that is verified, and for a house in Occupancy Group R-3 final inspection is not complete until then.
Handover. At final inspection the builder leaves copies of the signed compliance documents in the building for the owner.

A gap at any stage holds up the next one, which is why the energy work is best done while the drawings can still change. The full sequence, with who signs what, is set out in Title 24 compliance in California.

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