Cool Roofs in California: The Code.

If you replace most of a roof in California, the state energy code may require a "cool roof." This page explains what that means, when it applies and how to check a product. It covers single-family homes. Apartment and commercial buildings have their own rules.

What a cool roof is

The Cool Roof Rating Council (CRRC) describes a cool roof as one that strongly reflects sunlight and also gives off the heat it absorbs. Two numbers measure this:

• Solar reflectance. How much sunlight the surface bounces back.
• Thermal emittance. How well the surface releases heat it has taken in.

Both run from 0 to 1. Higher is cooler. The code uses "aged" values. The California Air Resources Board says aged products are weathered outside for three years. A third number, the Solar Reflectance Index (SRI), combines the two. The code lets you meet an SRI value instead of the two separate values.

A cool roof does not have to be white. CRRC says many "cool color" products use darker pigments that reflect the part of sunlight we cannot see.

When the rule applies to a reroof

The California Energy Commission says the cool roof values apply to alterations "where more than fifty percent of the roof is replaced." The California Air Resources Board describes the single-family rule the same way. If you replace half the roof or less, the reroof values do not apply under this section.

The 2025 values for single-family reroofs

The 2025 California Energy Code took effect on January 1, 2026. The CRRC summary of that code lists these minimums for new roofing on single-family reroofs:

California has 16 building climate zones. The Energy Commission has a free search tool that shows the zone for an address. It also notes that some ZIP codes cross more than one zone, and a city may pick one zone for the whole ZIP code. Check the tool, or ask your building department, rather than guessing.

Exceptions for steep roofs

For steep-sloped reroofs, the 2025 code treats any one of these as equal to meeting the cool roof values:

1. A ceiling with a U-factor of 0.025 or lower, or at least R-38 ceiling insulation.
2. A radiant barrier in the attic that meets the code's radiant barrier section, when it is not installed directly above spaced sheathing.
3. In climate zones 2, 4, 9, 10, 12 and 14, no ducts in the attic.
4. R-2 or greater continuous insulation above or below the roof deck.

Two more exceptions apply to both steep and low roofs. Roof area covered by building-integrated solar panels does not have to meet the values. Roof constructions weighing at least 25 pounds per square foot are also exempt. For low-slope roofs, the code also lets you trade the reflectance value for added insulation at the roof deck, using a table in the code.

Products must be rated

The Energy Commission says only aged values listed in the CRRC Rated Products Directory can be used to meet the cool roof rules. Rated products carry a CRRC label. A product with no rating must use default values. The 2025 code sets those defaults at 0.08 reflectance and 0.75 emittance for asphalt shingles, and 0.10 and 0.75 for other products. Those defaults are below the steep-slope minimum of 0.20.

You can look up any product in the CRRC directory at coolroofs.org/directory.

An example from a data sheet

Owens Corning's 2026 data sheet for its Duration COOL shingles says the line meets the prescriptive cool roof rules of Title 24, Part 6, and lists a CRRC product ID for each color. The listed solar reflectance values range from 0.17 to 0.29, and SRI values range from 16 to 29, depending on color. This shows why you should check the exact color, not just the product line. We cite it only as an example of how to read a data sheet.

The City of Los Angeles has its own rule

The City of Los Angeles adds its own cool roof rule in its green building code. CRRC's summary lists these minimums for low-rise homes:

• Steep slope (over 2:12): aged solar reflectance 0.25, thermal emittance 0.85, or SRI 20.
• Low slope (2:12 or less): 0.65, 0.85, or SRI 78.

CRRC lists these exceptions to the city rule: roof repair, replacing 50 percent or less of the roof, and roof replacement where solar systems are being installed. These values are higher than the state minimums. Confirm the current text with the Los Angeles Department of Building and Safety before you rely on it. Other cities may have their own rules too. See Reroof permit basics.

Questions to ask before you sign

• What climate zone is my address in?
• Is more than half the roof being replaced?
• What is the CRRC product ID for the exact color on the bid?
• Which exception, if any, is the bid relying on?

Our guide to reading a roofing estimate shows where these details should appear in writing.

Back to Roof types. Compare materials in Asphalt shingle vs. tile roofs.

This is general information, not legal, engineering or building code advice. Rules differ by city. Check with your local building department.