Title 24: Cool Roof Requirements for California
Solar reflectance, thermal emittance, and compliance requirements
Last updated: May 23, 2026
What is Title 24?
Title 24 is California's Building Energy Efficiency Standards, part of the California Code of Regulations. Updated every three years, these standards ensure that new buildings and major renovations meet minimum energy efficiency requirements. The cool roof provisions help reduce energy consumption, improve comfort, and mitigate the urban heat island effect.
The 2025 Energy Code is in effect today for any building permit applied for on or after January 1, 2026. The prior 2022 cycle still applies to projects whose permit application was filed before that date. Both cycles include specific cool-roof provisions based on building type, climate zone, and roof slope. These requirements apply to new construction, additions, and re-roof or recover projects covering more than 50% of the existing roof.
Cool-roof prescriptive values for single-family residential and nonresidential did not change between the 2022 and 2025 cycles. What changed in 2025: multifamily Option D coverage expanded to additional climate zones, and the multifamily steep-slope Option B prescriptive value tightened to 0.25 aged solar reflectance / 0.75 thermal emittance / SRI 23 in zones 10, 11, 13, and 15.
Cool Roof Requirements
Cool roofs reflect more sunlight and absorb less heat than standard roofs. Title 24 specifies minimum performance values for aged solar reflectance and thermal emittance, which together determine the Solar Reflectance Index (SRI).
Single-Family Residential — Prescriptive Cool-Roof Values
Title 24 §150.1 (new construction) and §150.2 (re-roof / alteration).
| Scope | Slope | Climate Zones | Aged Solar Reflectance | Thermal Emittance | SRI |
|---|---|---|---|---|---|
| New construction | Steep (>2:12) | 10–15 | 0.20 | 0.75 | 16 |
| New construction | Low (≤2:12) | 13 and 15 | 0.63 | 0.75 | 75 |
| Re-roof / alteration | Steep | 4, 8–15 | 0.20 | 0.75 | 16 |
| Re-roof / alteration | Low | 4, 6–15 | 0.63 | 0.75 | 75 |
Single-family values are identical in the 2022 and 2025 cycles. Source: California Energy Code Part 6, Sections 150.1(c)11 and 150.2(b)1.
Nonresidential and High-Rise — Prescriptive Cool-Roof Values
Title 24 §140.3 (new) and §141.0 (alterations).
| Scope | Slope | Climate Zones | Aged Solar Reflectance | Thermal Emittance | SRI |
|---|---|---|---|---|---|
| New, nonresidential | Low | All zones | 0.63 | 0.75 | 75 |
| New, nonresidential | Steep | 1 and 3 | 0.20 | 0.75 | 16 |
| New, nonresidential | Steep | 2 and 4–16 | 0.25 | 0.80 | 23 |
| New, hotel/motel guest rooms | Low | 9–11, 13–15 | 0.55 | 0.75 | 64 |
| New, hotel/motel guest rooms | Steep | 2–15 | 0.20 | 0.75 | 16 |
| Re-roof, nonresidential | Low | All zones | 0.63 | 0.75 | 75 |
Nonresidential values are identical in the 2022 and 2025 cycles.
"Aged" values represent the solar reflectance after three years of weathering under the CRRC field-exposure protocol. The Cool Roof Rating Council (CRRC) publishes rated values that account for this aging process. When a product has only an initial reflectance, Title 24 §10-113 defines how to derive the aged value.
Climate Zone Requirements
California is divided into 16 climate zones by the California Energy Commission. The prescriptive tables above show the specific zones each cool-roof requirement applies to, so this section is a quick reference for locating your project's zone.
Find your climate zone using the California Energy Commission's official lookup tool (search "California climate zones" on energy.ca.gov), which accepts a project address or ZIP code. Climate zones are tied to CEC reference weather stations — not city limits — so a single municipality often spans multiple zones. For a project that sits near a zone boundary, the building department's determination is authoritative. Representative zones for common reference weather stations:
- San Francisco: Zone 3
- Los Angeles International (LAX) area: Zone 6
- San Diego International area: Zone 7
- Long Beach area: Zone 8
- Hollywood Burbank area (San Fernando Valley): Zone 9
- Riverside / inland LA basin: Zone 10
- Sacramento: Zone 12
- Fresno: Zone 13
- Palm Springs / Coachella Valley: Zone 15
- Truckee / mountain communities: Zone 16
Local jurisdictions may adopt reach codes that exceed the state minimum. Check with the authority having jurisdiction (AHJ) before specifying.
Compliance Options
Title 24 offers several paths to compliance for cool roof requirements:
1. Prescriptive Compliance
- Use CRRC-rated roofing products that meet minimum values
- Follow specific requirements for your building type and climate zone
- Document product ratings on CF1R forms
2. Performance Compliance
- Use approved energy modeling software
- Demonstrate overall building meets energy budget
- May allow trade-offs with other building components
3. Exceptions
- Roofs with ≥ 25 lb/ft² of thermal mass (heavy roofs)
- Roof areas covered by photovoltaic panels or solar collectors
- Roof repairs covering less than 50% of roof area
- "Aged reflectance ≥ 0.20 with qualifying insulation" — this is Exception 1 to §150.2(b)1Ii. It applies to steep-slope re-roofs in covered zones and offers four equivalent compliance paths: (a) ceiling U-factor ≤ 0.025 (or ≥ R-38 ceiling insulation), (b) attic radiant barrier meeting §150.1(c)2, (c) a building with no ducts in the attic in CZ 2, 4, 9, 10, 12, or 14, or (d) at least R-2 continuous insulation above or below the roof deck.
- Liquid-applied roof coatings: the 2025 cycle adds additional requirements for liquid-applied products under §110.8(i)1-4. Verify the specific provisions against the Energy Code text before specifying.
Inspection & Documentation
Building inspectors will verify Title 24 cool roof compliance through:
1. Product Documentation
- CRRC Product Rating Certificate
- Manufacturer's product data sheets
- Product labels showing CRRC ID number
2. Compliance Forms (2025 cycle)
- 2025-CF1R-ENV-04-E — Solar Reflectance Index Calculation Worksheet (the actual cool-roof form)
- 2025-CF2R-ENV-04-E — Roofing, Ventilation, and Radiant Barrier Installation Certificate
- Other 2025-CF1R-ENV-* worksheets (02-E area-weighted average, 06-E insulation layers) apply when relevant to the roof assembly
3. Field Verification
- Visual inspection of installed products
- Verification of product labeling
- Confirmation of proper installation
Pro tip: Pull the CRRC rating certificate from coolroofs.org/directory before installation and keep a copy on-site. Many roofing manufacturers also publish certificates on their own product pages. Blank 2025-cycle compliance forms are at the CEC's 2025 forms page.
Frequently Asked Questions
Which Title 24 cycle applies to my permit?
The 2025 Energy Code applies to any permit application filed on or after January 1, 2026. The 2022 cycle still applies to projects with earlier permit applications. Today (May 2026) every new permit application is on the 2025 cycle. Local jurisdictions cannot drop below the state minimum; some adopt reach codes that exceed it.
Did the cool-roof reflectance numbers change in the 2025 cycle?
For single-family residential and nonresidential prescriptive paths, the aged solar reflectance, thermal emittance, and SRI values did not change. The 2025 cycle did expand multifamily Option D coverage to additional climate zones and tightened the multifamily steep-slope Option B value to 0.25 / 0.75 / SRI 23 in zones 10, 11, 13, and 15.
What is the difference between aged and initial solar reflectance?
Initial reflectance is measured on a clean, newly applied product. Aged reflectance is measured after three years of CRRC field exposure (or computed from the initial value using the CRRC aged-value protocol). Title 24 prescriptive values are aged values, since real roofs accumulate dirt and weathering that reduce reflectance over time.
Are cool roofs required on every California building?
No. Cool-roof requirements vary by building type, climate zone, and roof slope. Nonresidential low-slope cool roofs are required in all 16 climate zones. Residential cool roofs are required prescriptively only in specific zones (single-family steep-slope re-roofs in zones 4, 8–15, and low-slope re-roofs in zones 4, 6–15). Heavy roofs (≥ 25 lb/ft²) and roof areas covered by PV or solar-thermal panels are exempt.
Can I use a liquid-applied coating to meet Title 24 cool-roof requirements?
Yes, if the coating carries a current CRRC rating that meets the prescriptive aged solar reflectance and thermal emittance for your project's climate zone and roof slope. The 2025 cycle adds additional requirements specific to liquid-applied roof coatings under §110.8(i)1-4 — verify those against the Energy Code text before specifying. See our elastomeric coating guide for application detail.
Title 24 Compliant Cool Roof Products
View our full selection of roof coatings or contact our technical support team for assistance with product selection and specification.
Additional Resources
For more information on Title 24 cool roof requirements:
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