Independent Testing - Solar Absorbance (Abs)
Solar absorbance is the amount of solar energy (visible, infrared and ultraviolet), that is absorbed by a substrate and is expressed as a value in percent from 0 to 100.
100 being the highest absorbance, (hot).
0 being the lowest absorbance, (cool).
When sunlight strikes a building envelope, solar energy is either absorbed by the substrate or reflected away from it. The type of substrate causes varying absorbance results which are expressed as a percent and is the amount of solar energy that the substrate retains.
Energy Star coatings have the ability to reduce the absorbance value of all construction surfaces to values as low as 0.097.
To put the measure of an absorbance value into clear perspective, below is an example of what is achieved by reducing the absorbance of plain galvanised metal roofing. The temperature values stated are based on a day with a temperature of 37 deg C.
Plain galvanised metal roofing
Substrate temperate @ 37 deg C 80 deg C
Energy Star coated galvanised metal roofing
Substrate temperate @ 37 deg C 41 deg C
Difference in substrate temperature 39 deg C