Cool Roof
Coating Savings
by Climate

A cool roof coating is a liquid-applied, usually white coating that raises a roof's solar reflectance while keeping thermal emittance high, so the roof absorbs less sun and sheds heat fast. Clean bright white reflects about 85% of sunlight; a standard gray roof about 20%. Acrylic, silicone and topcoated polyurea can all qualify.

Yes, mostly in warm climates. The Cool Roof Rating Council puts average savings at 7–15% of cooling costs, and measured Florida houses saved 10–43%, averaging 19%. LBNL modeling found net savings for commercial buildings in every U.S. state. Well-insulated roofs save less than poorly insulated ones.

Sometimes. A cool roof loses some free winter heat, but northern winter sun is only about 20–35% of summer's, and snow often covers the roof. Commercial studies found net savings in Minnesota, Toronto and Anchorage. For homes in zone 4C and colder, PNNL expects near-zero or negative savings.

For low-slope roofs, codes ask for an aged SRI of 64 (IECC 2024, zones 0–3), 75 (California Title 24) or 82 (Los Angeles and New York City). Clean black scores about 0 and clean white about 100; very reflective coatings exceed 100. Compare products on the 3-year aged value.

No. EPA ended the ENERGY STAR roof products program on June 1, 2022, saying commercial codes had surpassed it. Its old low-slope levels were 0.65 initial and 0.50 aged solar reflectance. Today, look up the product's Cool Roof Rating Council rating, which reports initial and 3-year aged values.

Acrylic costs less, suits roofs that drain well and can later take acrylic or silicone. Silicone handles ponding water that degrades acrylic, but it tends to pick up dirt, gets slick when wet and can only be recoated with silicone. Both come in bright white, so choose on drainage, traffic and recoat plans.

Yes. Sprayed polyurea builds a thick, seamless membrane that takes foot traffic well. Aromatic polyurea is strong but less UV-stable, so it gets a white aliphatic topcoat; aliphatic polyureas such as ArmorThane's ArmorFlex UV are color-stable on their own. Ask for the white surface's CRRC rating.

It starts losing reflectance right away. LBNL's rule of thumb is bright white dropping from 0.85 to 0.65 in three years, and white membranes in DOE-funded tests lost about 0.15–0.20 over 36 months. Cleaning can restore up to 90% of initial reflectance, though energy savings alone rarely justify it.

Installed prices we found run about $0.50–$4.50 per square foot for mobile home roofs (HomeGuide, 2024), $1.50–$4.50 for silicone and $3.00–$6.00 for sprayed polyurea. The DOE put coating an existing smooth dark roof at $1.25–$2.40 in 2010 dollars. Choosing white over a standard color usually adds little.

Yes. Unpainted metal reflects sunlight well but has low thermal emittance, so it holds heat and rarely meets cool roof rules. A white coating raises both numbers. Treat rust, seal seams and fasteners, and use the primer the coating maker specifies before the reflective coat goes on.

Often, because a thin mobile home roof sits right over the living space. HomeGuide prices mobile home roof coating at $0.50–$4.50 per square foot, or $250–$5,400 for a single-wide, and recommends elastomeric acrylic or liquid rubber. Repair leaks, seams and rust first.

For many roofs, yes. The 2025 California Energy Code, effective January 1, 2026, requires nonresidential low-slope roofs, including re-roofs, to reach 0.63 aged solar reflectance and 0.75 emittance, or an aged SRI of 75. Some home climate zones also require cool roofs, and products must be CRRC-rated.