California energy rules push most Los Angeles reroofs toward a cool roof product with a rated reflectance.
At a glance
- Los Angeles County sits in climate zones 6, 8, 9, 14 and 16.
- Cool roof rules key off slope, climate zone and roof area.
- Every rated product has a CRRC label with two numbers.
- Your contractor files the paperwork with the permit.
What a cool roof is
A cool roof reflects more sunlight and releases more of the heat it does absorb. Two numbers describe it. Solar reflectance is the share of sunlight bounced back. Thermal emittance is how well the surface sheds heat it holds.
The Cool Roof Rating Council tests products and publishes both numbers. A product without a rating cannot be used to meet the requirement, no matter how light the color looks.
When the rule applies
The energy code treats a reroof as an alteration. Once you replace more than about half the roof area, or more than 2,000 square feet, the cool roof requirement comes into play.
Low slope roofs face a stricter target than steep slope roofs. Steep slope residential roofs in our zones generally need an aged reflectance around 0.20 with high emittance, and low slope roofs need much more.
Ways to comply without a white roof
Dark cool rated shingles exist and are common. The granule blend does the work, so the roof can look charcoal and still hit the number.
The code also allows trade offs. Added attic insulation, a radiant barrier, or ducts moved into conditioned space can offset a roof that misses the reflectance target. That path needs an energy calculation filed with the permit.
What to ask your roofer
Ask which product they plan to install, ask for the CRRC label sheet, and ask whether the job goes in as a prescriptive compliance or with a performance calculation.
Keep the label sheet with your house papers. A future buyer, an insurer, or the next roofer will want to know what is up there.
Common questions
Does a cool roof have to be white
No. Rated dark shingles and dark tile meet the residential steep slope numbers.
Does a small repair trigger the rule
No. Small repairs and patches fall under the area limits.
Who proves the roof complies
The contractor, through the permit package. Ask for a copy for your records.