The cool roof rule appears in several documents: the state Energy Code, the Green Building Code of the City of Los Angeles, which applies when more than half the roof is replaced, and product literature. They do not say the same thing.
The state values
For single-family alterations, the state rule takes hold past 50 percent of the roof replaced, with an overlay counted as replacement. Repairs, and replacements of half the roof or less, sit outside it.
On steep slopes, climate zone 4 and zones 8 through 15 call for 0.20 aged solar reflectance and 0.75 thermal emittance, with SRI 16 as the alternative. On low slopes, zones 4 and 6 through 15 call for 0.63 and 0.75, or an SRI of 75, and an insulation trade-off table offers another path.
The 2025 edition, in force since 1 January 2026, repeats the rule word for word. Executive Order N-29-25, the California Energy Commission reported in 2025, pauses some of those changes when a house lost in the 2025 Los Angeles fires is rebuilt.
The state also lists exceptions in the same section. Read both before assuming a roof is covered or exempt.
The City values
The Los Angeles Green Building Code has had a residential cool roof requirement, for jobs that replace more than half the roof, in full effect since 1 January 2015. For steep slopes, meaning over 2:12, the City asks for aged reflectance of 0.25 with emittance of 0.85, or an SRI of 20. Low slopes must reach 0.65 and 0.85, or an SRI of 78.
Roofs carrying solar, repairs, and replacements of half the roof or less fall outside the City requirement. A 2013 write-up lists lower steep-slope values; the 2022 LADWP sheet supersedes it as the later document.
When the permit is issued, a home replacing more than 50 percent of its roof must use a CRRC-labeled product.
How climate zones split the county
California divides its territory into sixteen climate zones, and the state publishes the zone for each ZIP code. Hollywood and Sherman Oaks fall in zone 9. Brentwood, Mar Vista, Santa Monica and Malibu are zone 6. Norwalk is zone 8. Palmdale and Lancaster are zone 14.
Count the City of Los Angeles by its 113 ZCTAs and 77 of them sit in zone 9. Zone 8 takes 21 of the rest, zone 6 takes 13, and zone 16 has just 2.
The zone matters because the steep-slope rule reaches only zone 4 and zones 8 through 15, which leaves zone 6 coastal steep roofs outside the state rule, while low slopes are covered there.
These counts are for City census areas and say nothing about a single address. Use the state ZIP lookup for yours.
Exceptions, and claims that are not exceptions
The state treats a steep-slope roof as compliant when the house has R-38 ceiling insulation, a radiant barrier not laid over spaced sheathing, an attic free of ducts in certain zones, or continuous insulation above or below the deck. The rule also leaves out roof area under solar panels and any roof of 25 pounds per square foot or more.
The exceptions say nothing about tile profile, raised battens or the air space under a tile. Some manufacturer literature suggests otherwise. The code text does not say so.
When a product page or a salesperson claims an exemption, ask for the code section.
A roof partly under panels and partly open is judged by the area that is not covered. The assessment should state which area that is.
Reading a listing
Every compliant product has a CRRC listing with aged solar reflectance and thermal emittance, and sometimes SRI. Match the listing number on the label to the directory, read the aged values and compare them to the table for your slope and zone.
Aged values matter, since new surfaces test higher than weathered ones. The label should show the product name, the number and the aged figures.
Keep the label or the carton. The inspector may ask for it, and in the City the contractor or owner-builder signs the certificate.
If the listing cannot be found, or the carton shows only a color name, ask for the maker's technical sheet. A product without a published aged value cannot show that it meets the rule.
For a roof that mixes slopes, each part is checked against its own values. A low-slope section over an addition can fall under the rule in a zone where the steep main roof does not, so the scope should list each section with its slope and the listing number of the product proposed for it.
Cool roof questions
Does tile profile or batten height exempt a roof from the cool roof values?
No. The state exceptions cover insulation, a radiant barrier not over spaced sheathing, duct location, continuous insulation, roof area under solar panels and heavy roofs. Tile profile, raised battens and the air space under tile are not among them.
How do climate zones split across the county?
By ZIP code. Hollywood and Sherman Oaks are zone 9, coastal Santa Monica and Malibu are zone 6, Norwalk is zone 8, and Palmdale and Lancaster are zone 14. The state publishes the list.
How do I look up a product's listing?
Find the product in the CRRC directory by name or listing number and read the aged reflectance and emittance. Compare them with the values for your slope and zone.