As reported by a Columbia University Study, the concept of “cool roof” can cut your energy usage.

The concept is very straight forward rather have a black (dark) roof which absorbs the sun’s rays and increase the building temperature, painting a highly reflective coating on the roof surface will reflect the rays away from the building  keeping the heat away, reducing your energy usage to cool your commercial building.

It is not as simple as just grabbing a can of white paint.  The ideal “albedo” (the fraction of light hitting an object that is reflected back) for a white roof is 1.0, a typical tar and gravel roof has a rating of .03-.2 and just “White Paint” is changes it to .15-.35.  Where if a qualified roofing contractor uses highly reflective roof coatings it can be changed to .6-.7.

According to the study an average black roof can reach 176°F in the summer peak while where a white reflective roof is 30° cooler.  A surprising finding was that the white reflective roof coating did not show the same 30° difference on cold nights.  Nor did they have any winter heat penalty (the need a dark roof to help keep snow and ice off roof).

In the winter a black roof can cool down to -4°F in contrast the reflective white roof is just below freezing.  The extreme temperature swing of the black roof in the Northeast can shorten the life span of a black roof. This supports the claim that the reflective white roof has a longer life span, due to the fact that temperature swing is not so severe.

For more information on reflective white roofs, and how coatings can save you money visit roof