Roof Coatings…Why white roofs are a better alternative?
We use coating systems that are certified by the Cool Roof Rating Council or, CRRC. Our white roof coating systems are solar reflective, reflecting up to 90% of sunlight. Traditional black roofs reflect only around 20%. The benefit of a white roof is measured partly according to the solar reflectance index, or SRI. A roofs SRI is a measure of a surfaces ability to reflect solar heat. SRI measures the reflectance of the sun’s rays and the thermal emittance or, the roofs ability to radiate absorbed heat. If you’ve ever worn a black t-shirt in the sun, you realize that the color black’s reflectance is negligible and its emittance is zero. Black absorbs and holds heat. A white roof, like a white t-shirt, has a reflectance as high as 90% and its emittance is 100%.
Why do we need white roofs?
Over the years we have replaced vegetation with buildings and roads which has resulted in The Urban Heat Island effect. There is a measurable increase in ambient urban air temperatures resulting from all of the black surfaces within our urban communities. Roofs and roads in urban settings are full of these heat trapping black surfaces. On a clear night, the temperature in a city with a population of 1 million or more can result in increased temperatures of up to 22 degrees higher than in those of neighboring suburbs; the Urban Heat Island Effect.
The real costs of The Urban Heat Island Effect…
The Urban Heat Island Effects include increased summer energy use, stress on the power grids, increased pollution levels, and even health hazards such as asthma.
We believe that there is a simple solution and we intend to do our part.
At Roofing & Exteriors of Virginia, we know that 5-10% of summer electricity is used to compensate for the Urban Heat Island effect and we want to do our part to reduce those numbers. Americans spend about $40 billion dollars annually to air conditioning! White roofs can reduce summer energy use by 10-40%, saving money and preventing pollution. It is estimated that white roofing alone can reduce the impact in a city by 1-2 degrees Fahrenheit. This is enough to lower peak energy demand and reduce the risk of brownouts and blackouts.