Cool Roofs and Title 24 in LA County: What Homeowners Need to Know

California's building energy requirements can affect roof replacement specifications. The applicable provisions depend on the code edition, climate zone, building type, roof slope and scope of work. Confirm those details before choosing materials; a single county-wide rule is not enough to specify a compliant roof.

Here's what actually applies, when, and how to comply without overspending.

What "cool roof" actually means

A cool roof is designed to limit solar heat absorption and release absorbed heat. Product ratings distinguish these properties:

• Solar reflectance describes how much incoming solar energy a surface reflects.
• Thermal emittance describes a surface's ability to release heat through thermal radiation.
• Solar Reflectance Index (SRI) is a calculated value that combines reflectance and emittance under standard conditions; it is not the same measurement as reflectance.

The Cool Roof Rating Council directory lists rated product values, including initial and aged values where available. Match the exact product and color, not just a brand name.

When Title 24 cool-roof applies

Do not assume that one percentage-of-roof threshold decides every project. The applicable code edition, building classification, slope, climate zone, alteration scope and exceptions must be checked.

Roofing work in Los Angeles County and Ventura County must meet the applicable California energy requirements. Confirm which Title 24 provisions apply to the property's climate zone, roof type and project scope with the local permitting authority before choosing materials.

The California Energy Commission's 2025 Energy Code page states that permit applications made on or after January 1, 2026 must comply with that code edition. Use the applicable compliance manual and local permitting guidance for the project-specific roof requirements.

Cost impact

Compare the installed cost of suitable products rather than assuming compliance creates either a large premium or no additional cost:

• Shingles and tile: compare the exact product, color, rated performance and installation requirements.
• Membranes and coatings: check substrate suitability and product ratings; a white appearance is not certification.
• Metal roofing: verify the specified finish and rated product rather than assuming all metal roofs perform alike.
• Complete assembly: include preparation, flashings, access, disposal and any other required compliance work.

Appearance and performance need to be considered together. Ask which suitable colors and products meet the project's requirements; do not assume all dark products fail or all light products comply.

How we handle compliance

Before approving the proposal, ask for the exact material specification, applicable rated values and an explanation of how required compliance documentation will be provided. The roof surface shown in a portfolio photograph does not prove that a particular product or assembly is certified.

If a contractor quotes you a re-roof without addressing Title 24, ask specifically how compliance will be documented. "Don't worry about it" isn't an answer — open permits and failed inspections create real problems when the home sells.

What homeowners can do

When getting quotes:

1. Ask each contractor explicitly: "What's the cool-roof rating of the material you're quoting?"
2. Confirm the rating meets Title 24 for your roof slope (steep vs. low).
3. Ask how compliance documentation will be submitted with the permit.

Discuss appearance, rated performance and any permitted alternatives before ordering materials. Read our cool roof service information and roofing materials comparison, then confirm the property's specific requirements with the permitting authority.