Residential Roofing Solar Reflectance Index

A value of 0 indicates that the material absorbs all solar energy and a value of 1 0 indicates total reflectance.

Residential roofing solar reflectance index. It is defined so that a standard black reflectance 0 05 emittance 0 90 is 0 and a standard white reflectance 0 80 emittance 0 90 is. Solar reflective shingles are designed specifically to reduce the absorption of the suns infrared radiation by reflecting ir rays off the surface of the roof thus not allowing the heat to be transferred to the interior of the structure i e. For example a standard black asphalt shingle would have an sri in the low single digits. Sri measures the roof s ability to reject solar heat defined such that a standard black reflectance 0 05 emittance 0 90 is 0 and a standard white reflectance 0 80 emittance 0 90 is 100.

Another method of evaluating coolness is the solar reflectance index sri which incorporates both solar reflectance and emittance in a single value. Installing a cool roof can cut your energy costs while contributing toward a better environment. The third metric used to measure the performance of cool roof coverings is called the solar reflectance index sri. Solar reflectance index sri.

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. The sr value is a number from 0 to 1 0. By lessening the demand for energy it decreases carbon emissions that cause pollution. The higher the sri the cooler the roof will be.

The us department of energy defines the solar reflectance index sri as a measure of the roof s ability to reject solar heat as shown by a small temperature rise. Incorporates both solar reflectance and thermal emissivity in a single value. The guide to choosing a cool roof. Solar reflectivity r solar reflectance index sri by color.

Sri measures the roof s ability to reject solar heat defined such that a standard black reflectance 0 05 emittance 0 90 is 0 and a standard white reflectance 0 80 emittance 0 90 is 100. It also must meet the specific solar reflectance thermal emittance and or solar reflectance index values defined by the specific energy code. Furthermore it doesn t store as much thermal energy as an ordinary roof. 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.

California s building energy efficiency standards for residential and nonresidential buildings title 24 part 6 contains requirements for the thermal emittance three year aged reflectance and solar reflectance index sri of roofing materials used in new construction and re roofing projects. The attic under the roof.