Roof color is the first step toward energy savings.
White or near white roofs are preferred.
The higher the emissivity, the faster a roof surface reradiates its heat to the sky.
Compare solar absorptance, albedo (overall solar reflectance), and emissivity for selection of the optimum materials.
Combination of high albedo and high emissivity resists solar heat gain most effectively.
(which also promises to reduce the heat island effect in urban areas.)
A solar reflectance index (SRI) allows quick comparisons between roofing products
Lower SRI is worse than higher SRI
0 = 5% albedo and 90% emittance (close to black asphalt shingles)
100 = 80% albedo and 90% emittance (close to EPDM white single ply roofing)
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