Cool Roof Rating Council (CRRC)

The Cool Roof Rating Council (CRRC) is a non-profit organization in the United States that develops methods for evaluating and labelling the radiative properties of roofing and exterior wall products. Its ratings are the main reference for solar reflectance (how much sunlight a surface reflects) and thermal emittance (how readily it sheds absorbed heat as infrared radiation) in North American energy codes and green building programs.

What the CRRC does

• Rates products. Manufacturers submit products to accredited laboratories for testing. Rated values are published in the CRRC's Roof Products Directory and Wall Products Directory.
• Tracks ageing. Ratings report both initial values and aged values after outdoor weathering, because dirt, biological growth and weathering reduce reflectance over time.
• Checks ratings. The CRRC conducts random testing of listed products to verify that published values hold.
• Publishes a standard. Its rating procedures are formalized in ANSI/CRRC S100, an American National Standard for test methods for radiative properties.

The CRRC does not set minimum performance levels. It reports values; codes and programs decide which values qualify as a "cool roof."

Why the ratings matter

A white roof that reflects 80% of sunlight can stay about 31 °C (55 °F) cooler on a summer afternoon than a grey roof reflecting 20%, according to Lawrence Berkeley National Laboratory. Lower roof temperatures reduce cooling energy use in buildings and help reduce urban heat islands. Thermal emittance matters because a highly reflective surface that cannot shed heat (such as bare metal) still runs warmer than its reflectance alone suggests.

Use in codes and programs

CRRC-rated values are referenced by energy codes such as California Title 24 and ASHRAE 90.1, by green building programs including LEED, and by local cool roof ordinances. The US EPA notes that cool roof requirements appear in codes or ordinances in a number of states, cities and counties. Since the ENERGY STAR roof label ended in 2022, the CRRC directory has become the main listing for reflective roofing in North America.

Related metrics

Solar reflectance and thermal emittance can be combined into a single number, the Solar Reflectance Index (SRI), which some programs use instead of separate values.