The Heat Island Group at Lawrence Berkeley National Laboratory works to cool buildings, cities, and the planet by making roofs, pavements, and cars cooler in the sun.
One way to measure how "cool" a roof can be is by calculating its Solar Reflectance Index (SRI). The SRI calculation can also be used to estimate the surface temperature of the roof product under prescribed conditions. To calculate SRI, download the SRI Calculator and enter the solar reflectance value (R) and the thermal emittance value (E) as decimals, then click on "Update SRI". Note: macros must be enabled in Excel.