Econo Roofing Blog
Cool Roof Guide: Title 24 Compliance in California
Last updated March 31, 2026
California needs cool roofs on most new and re-roofing projects. Here is what qualifies, what it costs, and how much you save in the Central Valley.
The Central Valley is one of the hottest regions in California. Summer heat in Modesto, Merced, Stockton, and Fresno routinely hit 100 to 115 degrees. A standard dark roof absorbs up to 90% of that solar energy, superheating your attic to 150 degrees or more. Your air conditioner fights that heat all summer long.
A cool roof changes the equation. By reflecting solar radiation and releasing absorbed heat efficiently, a cool roof keeps your home cooler, cuts energy bills, and meets California's building code requirements. This guide covers everything Central Valley homeowners need to know.
What Makes a Roof "Cool."
A cool roof is not a specific product. It is a performance standard defined by three measurable properties.
Solar Reflectance measures how much sunlight the roof reflects back into the atmosphere. A standard dark asphalt roof reflects about 5 to 15% of solar energy. A cool roof reflects 25% or more. Higher reflectance means less heat absorbed into the building.
Thermal Emittance measures how well the roof releases whatever heat it does absorb. Most roofing materials have high emittance naturally (0.75 to 0.95 on a scale of 0 to 1). Metal roofs without coatings can have lower emittance, which is why reflective coatings matter.
Solar Reflectance Index (SRI) combines both measurements into a single number from 0 to 100. A standard black roof scores around 1. A clean white roof scores around 100. California does not use SRI directly in code, but it is the industry standard for comparing cool roof products.
California Title 24: The Requirements.
California's Title 24 Building Energy Savings Standards set mandatory cool roof rules for most construction and re-roofing projects. The Central Valley falls within climate zones 11 through 13, which carry some of the strictest rules in the state due to extreme summer heat.
Steep-slope roofs (the standard pitched roof on most homes) must meet a minimum aged solar reflectance of 0.20 and heat emittance of 0.75. This applies to all new construction and most roof replacement projects.
Low-slope roofs (flat or near-flat, common on commercial buildings) face stricter standards: minimum aged solar reflectance of 0.63 and heat emittance of 0.75.
There are exceptions. If your roof does not meet cool roof minimums, you can compensate with more attic insulation or other approved energy trade-offs. Your contractor handles this calculation as part of the permit process.
The 2025 Title 24 update, good January 2026, tightened rules further. More roofing projects now trigger compliance, and the prescriptive path needs higher-performing materials in hot climate zones.
Which Materials Qualify.
Many roofing materials meet or go over Title 24 cool roof standards. The right choice depends on your roof type, budget, and looks preference.
Cool-rated asphalt shingles. Major makers including Owens Corning, GAF, and CertainTeed produce shingles with infrared-reflective granules. These look like standard shingles but reflect the invisible infrared spectrum that causes heat gain. Available in light and dark colors. Premium: 10 to 20% over standard shingles.
Metal roofing. Factory-finished metal panels with reflective coatings achieve solar reflectance values above 0.60, far over Title 24 minimums. Standing seam and metal shingle profiles offer the best energy performance of any common roofing material. See our full materials comparison.
Concrete and clay tile. Light-colored tile naturally meets cool roof standards. Even medium-toned tiles with reflective coatings can qualify. Tile lasts 50+ years, making it a strong long-term investment.
Single-ply membranes (TPO and PVC). The standard choice for flat commercial roofs. White TPO and PVC membranes easily go over Title 24 rules with reflectance values of 0.70 or higher.
Roof coatings. Elastomeric and silicone coatings can convert an existing roof to cool roof standards. Applied over shingles, metal, tile, or flat membranes. This is the most affordable path to compliance without a full replacement.
Cost: Cool Roof vs. Standard.
| Material | Standard Cost | Cool Roof Premium | Payback Period |
| Asphalt shingles (cool-rated) | $8,000 – $15,000 | +$500 – $1,500 | 2 – 4 years |
| Metal roofing (reflective) | $12,000 – $28,000 | Included | 8 – 12 years |
| Concrete/clay tile | $15,000 – $35,000 | +$0 – $1,000 | 3 – 6 years |
| TPO/PVC membrane | $5,000 – $12,000 | Included | 3 – 5 years |
| Roof coating (retrofit) | $2,000 – $6,000 | N/A (is the upgrade) | 2 – 5 years |
For most Central Valley homes, the cool roof premium is modest. Reflective metal roofing and TPO membranes include cool roof performance by default, so there is no premium at all.
Energy Savings in the Central Valley.
The Central Valley's extreme heat makes cool roofs especially good here. Energy-efficient roofing delivers measurable savings that compound year after year.
Surface temperature reduction: A cool roof runs 50 to 60 degrees cooler than a standard dark roof on a peak summer day. Where a dark shingle reaches 160 to 170 degrees, a cool roof stays at 100 to 120 degrees.
Attic temperature reduction: 20 to 40 degrees lower attic heat mean less heat radiating into your living space.
Cooling cost reduction: 15 to 30% lower summer electricity bills. For a home spending $300 to $500 monthly on summer power, that is $45 to $150 in monthly savings during June through September.
Annual savings: $200 to $700 per year for a typical Central Valley home, depending on roof size, material, and current HVAC savings.
How Cool Roofs Affect Your HVAC.
Your air conditioner is the single largest electricity consumer in a Central Valley home. It runs 6 to 8 months per year. A cool roof directly reduces the work your HVAC system has to do.
With lower attic heat, your AC cycles less often and runs for shorter periods. The compressor operates under less stress. Ductwork in the attic (common in California homes) loses less cooled air to heat gain. The cumulative effect: your HVAC system lasts longer, needs fewer repairs, and costs less to operate.
Homeowners who pair a cool roof with proper attic insulation and sealed ductwork see the greatest benefit. The three upgrades work together to cut heat transfer from roof to living space.
Rebates and Incentives.
Several programs help offset the cost of cool roof install in California.
Utility rebates. PG&E and other California utilities offer rebates for qualifying cool roof installs. Rebate amounts vary by program year and material type. Check with your utility or ask your contractor for current availability.
Federal tax credits. The Inflation Reduction Act provides tax credits for energy-good home improvements, including certain cool roof systems. Credits apply to the material cost and can be combined with other energy upgrades.
Local incentives. Some Central Valley cities and counties offer more rebates through climate action plans. Stanislaus County, San Joaquin County, and Merced County have all offered energy savings incentives in new years.
Insurance discounts. Some homeowners insurance providers offer premium reductions for cool roofs, impact-resistant materials, or recently replaced roofs. Ask your insurer about available discounts.
Our Cool Roof Installation Process.
Econo Roofing has installed cool roofs across the Central Valley since 1996. As the only Owens Corning Platinum Preferred contractor in Stanislaus and Merced County, we have access to the highest-performing cool roof products from every major maker.
Step 1: Free inspection. We assess your current roof condition, measure your roof area, check attic ventilation and insulation, and identify the climate zone rules for your property.
Step 2: Material selection. We suggest cool roof products based on your budget, looks choices, and energy goals. Every option we present meets or is over Title 24 rules for your climate zone.
Step 3: Permitting. We handle all permits and Title 24 compliance records. This includes energy calculations, material specs, and any needed trade-off records.
Step 4: Installation. Our crews follow maker specs for every product. Proper install is key for cool roof performance. Improper ventilation or underlayment can undermine energy savings.
Step 5: Inspection and warranty. We schedule the city inspection, walk you through maintenance, and register your maker warranty. As a certified installer for Owens Corning, GAF, and CertainTeed, we can offer warranties up to 50 years.
Frequently Asked Questions.
What is a cool roof?
A cool roof is a roofing system designed to reflect more sunlight and absorb less heat than a standard roof. Cool roofs achieve this through high solar reflectance (the ability to reflect sunlight) and high heat emittance (the ability to release absorbed heat). Performance is measured using the Solar Reflectance Index, or SRI, which combines both metrics into a single number from 0 to 100.
Does California require cool roofs?
Yes. California's Title 24 Building Energy Savings Standards require cool roofing on most new construction and re-roofing projects. The rules are strictest in climate zones 10 through 15, which includes the entire Central Valley. Steep-slope roofs must achieve a minimum aged solar reflectance of 0.20 and heat emittance of 0.75. Low-slope roofs require 0.63 reflectance and 0.75 emittance.
What roofing materials qualify as cool roofs?
Several materials qualify as cool roofs in California. Cool-rated asphalt shingles with reflective granules, metal roofing with factory-applied reflective coatings, concrete and clay tile in lighter colors, single-ply membranes like TPO and PVC, and elastomeric or silicone roof coatings applied to existing roofs all meet Title 24 cool roof rules when properly rated.
How much does a cool roof cost compared to a standard roof?
Cool-rated asphalt shingles cost 10 to 20 percent more than standard shingles, adding roughly $500 to $1,500 to a typical residential roof. Reflective metal roofing runs $12,000 to $28,000 installed. Roof coatings that convert an existing roof to cool roof standards cost $1.50 to $4.00 per square foot. The premium pays for itself through energy savings within 3 to 7 years in the Central Valley.
How much energy does a cool roof save in the Central Valley?
In the Central Valley where summer heat regularly exceed 100 to 115 degrees, a cool roof reduces cooling costs by 15 to 30 percent. For a typical home spending $300 to $500 per month on summer electricity, that translates to $45 to $150 in monthly savings during peak cooling season. Annual savings usually range from $200 to $700 depending on roof size and material.
Are there rebates for cool roofs in California?
Yes. Several incentive programs exist for cool roofs in California. Utility companies including PG&E offer rebates for qualifying cool roof installs. The federal Investment Tax Credit can apply to certain cool roof systems installed with solar. Some local jurisdictions offer additional rebates through their climate action programs. Your roofing contractor should help identify all available incentives.
Can I add a cool roof coating to my existing roof?
Yes. Reflective roof coatings can be applied to most existing roof types including asphalt shingles, metal, tile, and flat roofing membranes. A expert coating costs $1.50 to $4.00 per square foot and can bring your existing roof into cool roof compliance while extending its life by 5 to 10 years. This is the most cost-good path to cool roof performance.
What SRI value does my roof need in California?
California Title 24 does not use SRI directly but instead specifies minimum solar reflectance and heat emittance values. For steep-slope roofs, the minimum aged solar reflectance is 0.20 with heat emittance of 0.75, which corresponds to an SRI of roughly 16. For low-slope roofs, minimum reflectance is 0.63 with 0.75 emittance, corresponding to an SRI of approximately 75. Higher SRI values provide greater cooling benefit.
Do dark-colored roofs ever qualify as cool roofs?
Yes. Modern cool roof technology includes dark-colored shingles and tiles that use infrared-reflective pigments to meet Title 24 rules. These materials appear dark to the eye but reflect the invisible infrared portion of sunlight that causes heat gain. Makers like Owens Corning, GAF, and CertainTeed offer cool-rated shingles in charcoal, brown, and other dark tones.
How does a cool roof affect my HVAC system?
A cool roof reduces the heat load on your HVAC system by lowering attic heat 20 to 40 degrees compared to a standard dark roof. This means your air conditioner cycles less frequently, runs for shorter periods, and operates more well. Over time this reduces wear on the compressor, extends equipment life by 2 to 5 years, and lowers maintenance costs. In the Central Valley where AC runs 6 to 8 months per year, the cumulative benefit is significant.