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Cool roofs explained: reflectance, emittance and ratings

A cool roof reflects more sunlight and sheds heat, so it stays cooler. How the CRRC rates products, where cool roofs help most, and the end of the 25C credit.

Disclaimer: Cost figures are rough educational estimates. Actual roofing prices depend on location, labor, structure, permits, tear-off, pitch, and market conditions. Always obtain written quotes from licensed local contractors. This is not a bid or insurance appraisal.

What makes a roof “cool”

A cool roof has high solar reflectance (it reflects more sunlight) and high thermal emittance (it gives off absorbed heat). The U.S. Department of Energy’s guide explains that this keeps the roof surface cooler and can cut cooling energy use, with the biggest benefit in hot, sunny climates.

How products are rated

The Cool Roof Rating Council (CRRC) lists products with their initial and 3-year aged solar reflectance and thermal emittance. Aged values matter because roofs get dirty and weather. Compare aged values when choosing.

Things to weigh

In cold climates, a cool roof can slightly raise winter heating needs.
Steep-slope options exist, including cool-coloured shingles, tile and metal.
Some cities and states have cool roof requirements; check local building codes.

Tax credit note

The IRS says the Energy Efficient Home Improvement Credit (section 25C) does not apply to property placed in service after 31 December 2025. Check IRS guidance for your own situation.

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FAQ

Does a cool roof have to be white?

No. Cool-coloured products use pigments that reflect infrared light, so darker colours can still rate well.

Where do I check a product's rating?

Search the CRRC Rated Products Directory.

Sources

Last checked: 29 October 2026.