California Title 24 Insulation Requirements for Contractors

Published July 3, 2026 · Prestige Insulation

California's Title 24 (Building Energy Efficiency Standards) is updated every three years and is among the most stringent energy codes in the country. The 2022 standards — effective January 2023 — raised requirements in nearly every climate zone. Here's what contractors need to know.

California climate zones

California uses 16 climate zones (CEC zones) rather than the IECC system. The zones broadly correspond to:

CEC Zone	Cities/Regions	IECC Equivalent
1–3	Humboldt, North Coast, Inland mountains	Zone 5–6
4–5	Sacramento Valley, San Jose, parts of SF Bay Area	Zone 3B–3C
6	Southern coast (Santa Monica to San Diego)	Zone 3B
7	San Diego inland (El Cajon, Escondido)	Zone 3B
8–9	Los Angeles basin, Orange County	Zone 3B
10	Inland Empire (Riverside, San Bernardino)	Zone 3B–4C
11–13	High desert (Palmdale, Victorville, Barstow)	Zone 4–5
14	Mountain areas (Big Bear, Tahoe)	Zone 5–6
15	Imperial Valley (El Centro, Palm Springs)	Zone 2
16	Mountains and high desert	Zone 6

2022 Title 24 insulation minimums

Assembly	Coastal (Zones 6–7)	Inland (Zones 8–10)	High Desert / Mountain
Wall (2×4 framing)	R-13	R-15 HD	R-21 (2×6 required)
Wall (2×6 framing)	R-19 or R-21	R-21	R-21 HD
Attic / Ceiling	R-38	R-38 to R-49	R-49 to R-60
Floor over crawl	R-19	R-19	R-30

Key changes in 2022

The 2022 code increased attic requirements and added requirements for continuous insulation on exterior walls in many inland climate zones. Notable changes:

• Many zones now require R-49 attic insulation where R-38 was previously sufficient.
• 2×4 wall construction is effectively prohibited in colder inland zones — 2×6 is now the standard.
• All-electric home requirements in many California jurisdictions have added pressure to maximize insulation to reduce heating loads.

Practical guidance for California contractors

• Coastal zones (LA, San Diego, Bay Area): R-21 for 2×6 walls, R-38 for attics — this satisfies most coastal zones. Verify with local jurisdiction.
• Inland / high desert: Spec R-21 HD walls, R-49 attic. Many projects in zones 11–14 require R-49.
• Sacramento, San Jose area: R-21 walls, R-38 to R-49 attic depending on specific zone.

Delivering to California

We deliver insulation to contractors across California — Los Angeles, San Diego, San Jose, San Francisco, Sacramento, and surrounding areas. Same-day quotes, next-day delivery. See our California delivery page →