What is a cool roof?
A cool roof is a roofing product tested and rated for solar reflectance (how much sunlight it bounces back) and thermal emittance (how well it releases heat). Ratings come from the Cool Roof Rating Council, and the Energy Code uses the aged values after weathering.
What does the Energy Code require?
For steep-slope roofs, the prescriptive minimum is an aged solar reflectance of 0.20 and a thermal emittance of 0.75, or a Solar Reflectance Index of 16, in climate zones 4 and 8 to 15. Low-slope roofs need 0.63 and 0.75, or SRI 75, in zones 4 and 6 to 15. The rule applies to reroofs replacing more than half the roof, and exceptions exist (CEC cool-roof guide).
Which North Bay cities need a cool roof?
| City | CEC climate zone | Steep-slope reroof: cool roof required? | Low-slope reroof: cool roof required? |
|---|---|---|---|
| San Rafael | 2 | No | No |
| Novato | 2 | No | No |
| Mill Valley | 3 | No | No |
| Larkspur | 2 | No | No |
| Sausalito | 3 | No | No |
| Petaluma | 2 | No | No |
| Santa Rosa | 2 | No | No |
| Rohnert Park | 2 | No | No |
| Sebastopol | 2 | No | No |
| Healdsburg | 2 | No | No |
| Sonoma | 2 | No | No |
| Windsor | 2 | No | No |
| Napa | 2 | No | No |
| American Canyon | 2 | No | No |
| St. Helena | 2 | No | No |
| Calistoga | 2 | No | No |
Climate zones are from the Energy Commission's ZIP code list (CEC climate zones); a few ZIPs straddle zones, so confirm yours with the city.
What's different about the North Bay?
Every North Bay city in our table falls in climate zone 2 or 3, so neither the steep-slope nor the low-slope prescriptive cool-roof rule applies to a home reroof here. That makes fire rating the bigger roofing rule in Sonoma, Napa and Marin: Permit Sonoma's bulletin B-07 sets Class A requirements for unincorporated Sonoma County (Permit Sonoma B-07).
What should I ask my roofer?
Ask the roofer to name the product and its CRRC listing on the estimate, and keep the label for your permit final. For your actual price, request a free written estimate: a licensed roofer measures the roof and prices your exact scope. See also metal vs. shingles, what drives cost and permits.
Every roofer we work with is licensed, insured and highly reviewed by Bay Area homeowners.
Get a free replacement quoteFrequently asked questions
Do cool roofs have to be white?
No. Many shingles and tiles in medium and dark colors carry cool-roof ratings.
What is SRI?
The Solar Reflectance Index combines reflectance and emittance into one number; the Energy Code accepts it as an alternative.
Sources
Sources reviewed November 12, 2026. Figures are published estimates and official fees, not quotes. Confirm prices, permits and requirements with your contractor and building department. This page is general information, not legal or insurance advice.