What Are the Parts of Title 24, and Which Is the Energy Code?
Title 24 is the California Building Standards Code, and its 2025 edition has thirteen parts, numbered 1 to 12 with a Part 2.5. The Energy Code is Part 6, and the compliance documents a building department asks for come from it and from the administrative rules that go with it in Part 1. The other parts cover everything else a building must meet.
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Part by part
- Part 1, Administrative Code. Each state agency’s administrative provisions. The Energy Commission’s administrative rules for Part 6 sit in its Chapter 10.
- Part 2, Building Code. Volumes 1 and 2, based on the 2024 International Building Code. Chapters 11A and 11B hold the accessibility rules (see accessibility versus the Energy Code).
- Part 2.5, Residential Code. Based on the 2024 International Residential Code. It does not print that code’s energy, mechanical, fuel gas, plumbing or electrical provisions and sends the reader to the other parts.
- Parts 3, 4 and 5. The Electrical Code (2023 National Electrical Code), the Mechanical Code (2024 Uniform Mechanical Code) and the Plumbing Code (2024 Uniform Plumbing Code).
- Part 6, Energy Code. Adopted by the Energy Commission and not based on a model code.
- Part 7, Wildland-Urban Interface Code. New for 2025 and based on the 2024 International Wildland-Urban Interface Code. It took over the wildfire construction rules that sat in Building Code Chapter 7A, Residential Code Section R337 and Fire Code Chapter 49.
- Part 8, Historical Building Code. Carried forward from 2022 without amendment. Qualified historic buildings are excepted from Part 6 (Section 100.0(a)).
- Parts 9 and 10. The Fire Code (2024 International Fire Code) and the Existing Building Code (2024 International Existing Building Code).
- Part 11, CALGreen. The green building standards, a California standard separate from Part 6 (see Title 24 versus CALGreen).
- Part 12, Referenced Standards Code.
Model codes and California standards
The Building Standards Commission’s guide says Parts 2, 2.5, 3, 4, 5, 7, 9 and 10 are based on model codes, with California amendments shown in italics. Parts 1, 6, 8, 11 and 12 are California standards. A model-code book from the publisher lacks the state’s changes, so use the Title 24 edition itself.
What is not a part of Title 24
Title 20, the appliance rules, and Title 25, housing, are separate titles of the California Code of Regulations. Title 24 versus Title 20 and Title 24 versus Title 25 sort them out.
Which edition and where to read it
The 2025 edition was published on 1 July 2025 and took effect on 1 January 2026, and it applies to permit applications from that date. The Title 24 code PDF page says where each part can be read, and what Title 24 is explains why the Energy Code is the part most projects mean.
Common Title 24 Questions
- What is Title 24?
- Do I need a Title 24 report?
- How much does a Title 24 report cost?
- How long does a Title 24 report take?
- What is included in a Title 24 report?
- What plans do I need to upload?
Frequently Asked Questions
No. Part 6 is the Energy Code, written by the Energy Commission. CALGreen is Part 11, a separate set of green building measures.
The 2025 edition moved them into Part 7, the Wildland-Urban Interface Code, from Building Code Chapter 7A and the other places they sat.
No. A building is designed to several parts at once, and the energy documents are one piece of that. The building department checks each part that applies.
Explore What Is Title 24?
- Residential vs Nonresidential Title 24: Which Rules Apply?
- Does Title 24 Require a Smart Thermostat?
- Title 24 Accessibility vs the Energy Code: Which Do You Mean?
- Where to Find the Title 24 Code PDF
- Title 24 vs ASHRAE 90.1: How They Relate
View all What Is Title 24? guides → · Title 24 Guide · Title 24 guide