Title 24, Part 6 is California's building-energy code — the rulebook that dictates how efficiently every new building, addition, and major alteration in the state uses energy. It is written and updated on a three-year cycle by the California Energy Commission (CEC), the state agency tasked with reducing California's building energy demand. The 2022 code is the outgoing version; the 2025 code has been in effect since January 1, 2026. Any addition, major alteration, or reroof-plus-addition triggers compliance. Title 24 is the reason a California kitchen remodel needs heat-pump consideration, LED lighting, and specific ventilation math — not because the contractor wants it, but because the code mandates it.
What Title 24 regulates
Part 6 is specifically building energy. The other parts of Title 24 cover structural, fire, plumbing, electrical, and accessibility — each enforced under its own code cycle. Part 6 narrows the lens to how a building creates, consumes, and loses energy. It governs envelope insulation (minimum R-values calibrated to climate zone), fenestration U-factor and Solar Heat Gain Coefficient (SHGC) on windows and doors, minimum HVAC equipment efficiency, water-heating equipment and distribution, lighting controls (occupancy sensors, dimming, daylight harvesting), and indoor-air-quality ventilation per ASHRAE 62.2. It also sets appliance minimums for covered equipment and, starting with the 2019 code and expanding through 2022 and 2025, photovoltaic (PV) and battery-storage requirements on new residential and certain nonresidential construction. California is divided into 16 climate zones, each with its own prescriptive envelope numbers — Climate Zone 6 (coastal LA) has very different insulation demands than Climate Zone 14 (high desert).
The 2025 code update — heat pumps + solar/storage expansion
The 2025 code doubled down on electrification. For a typical residential remodel: (a) a heat-pump water heater is the compliance-path baseline for new or replacement water heating — a gas tank will trigger compliance credits elsewhere; (b) heat-pump HVAC is favored over gas furnaces through performance-path credits, making all-electric the lower-friction path on paper; (c) PV plus battery-storage capacity scales with square footage on new residential construction, and storage sizing is no longer optional in many climate zones; (d) ventilation math tightened again, with stricter kitchen range-hood capture efficiency and whole-house ventilation assumptions. See the CEC's 2025 Energy Code summary page for the full chapter-by-chapter change log. The compliance trade-off: you can still install a gas appliance in 2026, but you'll pay for it with a credit somewhere else in the energy budget — usually a more aggressive envelope or a bigger PV array.
Prescriptive path vs performance path
Title 24 offers two compliance routes. The prescriptive path means following the table for your climate zone and meeting each envelope, HVAC, lighting, and ventilation number individually — no trade-offs, no software, just checkbox-by-checkbox conformance. The performance path means hiring a Title 24 energy consultant (sometimes called a "Title 24 engineer" or, for post-construction field verification, a HERS rater registered with a HERS provider) who runs CBECC-Res simulation software to demonstrate the whole building meets the energy budget, even if individual components are slightly below prescriptive minimums. Most remodels over $100K use the performance path because it lets the architect keep the design intent — big windows, open floor plans, preferred finishes — while still proving compliance through whole-building trade-offs.
Who enforces Title 24
The CEC writes the code; your local building department enforces it. In Los Angeles, that's LADBS; in San Francisco, it's the Department of Building Inspection (DBI); in San Diego, it's Development Services Department (DSD). Plan check rejects any project submitted without a Title 24 compliance report (the CF1R-PRF-01-E form for performance path, or the CF1R for prescriptive), and final sign-off at the Certificate of Occupancy stage requires HERS verification — a third-party field test of ducted systems, certain tested equipment (variable-speed equipment, refrigerant charge, blower-door envelope leakage), and PV/battery commissioning where applicable. HERS raters are independent verifiers registered through a HERS provider such as CalCERTS or CHEERS; your contractor can recommend one or the energy consultant typically contracts one.
What Title 24 means for homeowner remodels
Practical impact depends on what you touch. If you're doing a kitchen remodel that replaces the range hood, Title 24 dictates the minimum CFM and capture efficiency. If you're redoing a bathroom, the exhaust fan CFM and whole-house-ventilation contribution are dictated. If you're adding an ADU, Title 24 applies from the ground up — the ADU needs its own envelope numbers, its own HVAC sizing calculation, its own ventilation, and in 2025-and-later code, its own PV allocation if it's grid-connected and over the size threshold. For a partial remodel, the rule of thumb is straightforward: any system you touch becomes code-current for that system, but you aren't forced to re-code systems you don't touch. This is why a kitchen cabinet refresh and repaint doesn't trigger Title 24, but a kitchen remodel with new electrical, new appliances, and a new range hood does — and why a full-interior gut remodel effectively re-codes the entire conditioned envelope.
How AskBaily routes Title-24-aware contractors
AskBaily's California contractors are filtered for Title 24 performance-path fluency — meaning they've worked with a Title 24 energy consultant on prior projects and can coordinate CF1R paperwork, HERS verification scheduling, and the CBECC modeling feedback loop during design. Every California Tier-1 pillar on AskBaily (Hillside Ordinance, HPOZ, AB 1033, SB 9, Title 24 Compliance) cross-references this page where applicable, and homeowners routed through AskBaily for projects at or above $75K are matched only to contractors with documented Title 24 consultant relationships. That filter removes the 30–60 day plan-check delay that comes from a contractor learning performance-path Title 24 on your project for the first time.