Residential Roofing Solar Reflectance

Solar reflective shingles and solar reflective roofing membranes can be an important component in a building system designed to reduce overall building energy consumption and the impact the home or building has on the environment.

Residential roofing solar reflectance.

The most well known type of reflective surface is the cool roof. Solar reflectivity r solar reflectance index sri by color. It is defined so that a standard black surface reflectance 0 05 emittance 0 90 is 0 and a standard white surface reflectance 0 80 emittance 0 90 is 100. Meet the prescriptive solar reflectance and thermal emittance requirements according to the 2016 title 24 standards are rated by the cool roof rating council and meet the cool roof requirements of the los angeles green building code find out more about title 24 here.

As you re shopping for your new roof look for the tag or label solar reflectance. Solar reflectivity or reflectance is the ability of a material to reflect solar energy from its surface back into the atmosphere. These shingles must have an initial solar reflectance of at least 0 25 and a three year solar reflectance measurement of at least 0 15. Painting a metal roof can increase its solar reflectance and thermal emittance allowing it to achieve cool roof status.

How they can be made cool. Solar reflective shingles. Feature gaf proprietary color blends and enhanced shadow effect for a genuine wood shake look. A value of 0 indicates that the material absorbs all solar energy and a value of 1 0 indicates total reflectance.

The solar reflectance index sri is a measure of the constructed surface s ability to reflect solar heat as shown by a small temperature rise. Unpainted metals are typically good solar reflectors but poor thermal emitters so they rarely satisfy low slope cool roof requirements. This is a requirement in some energy codes. Residential roofing options include asphalt shingles metal clay tiles and concrete tiles.

Alternatively you can apply cool reflective coatings. Reflective surfaces can deliver high solar reflectance the ability to reflect the visible infrared and ultraviolet wavelengths of the sun reducing heat transfer to the surface and high thermal emittance the ability to radiate absorbed or non reflected solar energy. The sr value is a number from 0 to 1 0. All of these types of residential roofing products are now available with ir reflective color pigments which act to reduce the temperature of roofs and reflect heat away from the home.

Owens corning asphalt shingle products labeled as cool are rated with the cool roofing rating council ccrc for solar reflectance and thermal emittance. Innate reflectance is measured on a scale from 0 to 1 with the latter being the highest level of reflectivity meaning it reflects 100 of all radiant energy coming in contact with it.