“Cool roof” rules in California’s Energy Code (Title 24, Part 6) depend on two things: the building’s climate zone and the type of building. The 2025 Energy Code took effect on January 1, 2026, and the answer for most San Francisco homes is simpler than many roofers suggest.
Which climate zone is my Bay Area address in?
The California Energy Commission assigns building climate zones by ZIP code. From the CEC’s ZIP code list:
| City (ZIP codes checked) | Climate zone |
|---|---|
| San Francisco (94102, 94110, 94115, 94122, 94124) | 3 |
| Daly City (94015), South San Francisco (94080) | 3 |
| Oakland (94609, 94611), Berkeley (94704), Alameda (94501) | 3 |
| San Mateo (94402), Belmont (94002), Burlingame (94010), San Carlos (94070), Redwood City (94063), Menlo Park (94025) | 3 |
| San Leandro (94577), Fremont (94536), Mill Valley (94941) | 3 |
| San Rafael (94901) | 2 |
| Palo Alto (94301), Mountain View (94040), Sunnyvale (94087), San Jose (95112, 95125) | 4 |
| Lafayette (94549), Pleasanton (94566) | 12 |
Where a ZIP code spans two zones, the CEC notes that the local building department may assign one zone to the whole ZIP. Check your exact address with the CEC’s climate zone search tool or your building department.
What does the 2025 Energy Code require on a reroof?
The requirements below are from the Cool Roof Rating Council’s chart of the 2025 Energy Code and the CEC’s 2025 nonresidential cool roof page. They are prescriptive requirements, so a full energy calculation can sometimes show compliance another way.
| Building and roof | Climate zones where it applies | Minimum |
|---|---|---|
| Single-family reroof, steep slope (2:12 or steeper) | 4 and 8–15 | Aged solar reflectance 0.20 and thermal emittance 0.75, or SRI 16. Equivalent options include R-38 ceiling insulation, an attic radiant barrier, R-2 continuous deck insulation, or (in zones 2, 4, 9, 10, 12, 14) no ducts in the attic. |
| Single-family reroof, low slope (under 2:12) | 4 and 6–15 | Aged solar reflectance 0.63 and thermal emittance 0.75, or SRI 75. Roof-deck insulation can be used instead (Table 150.2-B). |
| Multifamily, more than 50% of the roof or 2,000 sq ft (whichever is less) | Low slope: 2, 4 and 6–15. Steep: 4 and 8–15 | Same values as single-family, with insulation alternatives. |
| Nonresidential, more than 50% of the roof or 2,000 sq ft (whichever is less) | Low slope: all zones. Steep: all zones | Low slope: 0.63 / 0.75 or SRI 75, or meet the roof U-factor table. Steep, zones 1 and 3: 0.20 / 0.75 or SRI 16. |
Roofs weighing at least 25 lb/ft² and roof area covered by building-integrated solar panels are exempt. Products used to meet a cool-roof requirement must be rated and labeled under the Cool Roof Rating Council program.
So what does that mean in San Francisco?
- Single-family houses: climate zone 3 is not on either single-family reroof list, so a pitched or flat house roof has no prescriptive cool-roof requirement. A white TPO membrane is still a sensible option on a sunny flat roof, but it is a choice, not a mandate.
- Multifamily buildings: zone 3 is not on the multifamily alteration lists either.
- Commercial and mixed-use buildings: a low-slope reroof covering more than half the roof or 2,000 sq ft needs a cool roof in every zone, including San Francisco. SF.gov’s reroofing permit page asks commercial projects of that size for cool roof information.
And in the rest of the Bay Area?
The answer changes once you leave the fog belt. San Jose, Palo Alto, Mountain View and Sunnyvale are zone 4, where single-family reroofs have both steep-slope and low-slope cool-roof requirements. Lafayette and Pleasanton are zone 12, where both apply too. That is why a roofer’s answer from a South Bay or inland job may not hold for your San Francisco house.
We check the climate zone for every job and list any cool-roof product, rating and compliance form in the written estimate. For flat-roof choices, see the best flat roof for a San Francisco house. For the general rules statewide, see Title 24 cool roof requirements.
Request a free inspection and written estimate or call (415) 410-7917.
Sources: CEC building climate zones by ZIP code; CRRC chart of 2025 California Energy Code cool roof requirements; CEC: 2025 nonresidential cool roofs; SF.gov: apply for a reroofing permit.
More questions
What climate zone is San Francisco in for Title 24?
Climate zone 3. Every San Francisco ZIP code checked in the California Energy Commission list (including 94102, 94110, 94115, 94122 and 94124) is assigned to building climate zone 3.
Does San Jose require a cool roof on a house reroof?
Often, yes. San Jose ZIP codes such as 95112 and 95125 are in climate zone 4, where the 2025 Energy Code sets cool-roof minimums for both steep-slope and low-slope single-family reroofs, with insulation-based alternatives.
Related services and local pages
- Roof Replacement
- Commercial & Residential Roofing
- San Francisco roofing contractor
- San Jose roofing contractor
- Roofing Permits in the Bay Area — How We Handle Yours
- Roofing materials guide
Sources
- California Energy Commission: building climate zones by ZIP code
- Cool Roof Rating Council: 2025 California Energy Code cool roof requirements (chart)
- California Energy Commission: 2025 nonresidential cool roofs
- California Energy Commission: Building Energy Efficiency Standards (Title 24)
- SF.gov: apply for a reroofing permit
Rules and maps change; confirm requirements for your address with your city or county building department.
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