As we here in Houston suffer through the hottest summer in recent times, we are forced to find new ways to keep energy costs down while maintaining a livable temperature in our homes and businesses. Often our ability to maintain the most efficient environments is predicated by the construction of the structures we are working to keep cool in the summer and warm in the winter.
One interesting fact I would like to share with my fellow Houstonians is the vast difference the color of our roofs can make in the cooling efficiency of our living environments. This will not affect those who live in multi-level buildings as much but single dwelling homes and commercial buildings can be subject to the intense sun and not just in the summer months.
It has been proven that on a 100 degree day the surface of a black asphalt roof can reach 182 degrees which will certainly radiate into the attic space and potentially your living space. Even if it makes just a one or two degree difference it will be part of your next power bill and could make your Air Conditioner work harder and longer than it should.
A white or at least a lighter colored roof can provide real benefits over the traditional black roof. It is said that the reflecting of as much as 80 percent of the solar radiation hitting your home or building can reduced air conditioning costs as much as 15 to 20 percent. I know that a white roof may not be feasible for residential applications but there are many new homes being built with lighter tan colored roofs and the benefits are being realized.
Commercial roof which are often flat or unseen can be treated with white coatings. According to Lawrence Berkeley Laboratories, white-coated roofs can reflect 60 to 85 percent of the solar energy that hits them and stay as little as nine degrees above air temperature. Dark-colored roofs, by contrast, typically reflect 20 percent of sunlight or less, and a black asphalt roof reflects only 5 percent.