What is a cool roof?
A cool roof is a reflective surface usually installed on commercial buildings. One of the main benefits of a cool roof system is that it offers an immediate and long-term reduction of air conditioning and heating usage to maintain a comfortable atmosphere through out the year.
Why are cool roofs white?
When the sun shines on a white roof, much of the untraviolet rays are reflected back through the atmosphere into space. When the sun shnes on a dark surface, about 15% of the sunlight is reflected. Most of the sunlight is absorbed and converted to heat, which then heats the atmosphere.
According to the US Department of Energy, “President Obama and Secretary Chu have made clear that the federal government should play a leading role in moving the nation toward a more sustainable future. Under President Obama’s Executive Order on Sustainability, the federal government has committed to reducing its greenhouse gas emissions 28 percent by 2020. As part of that effort, Secretary Chu has directed all DOE offices to install cool roofs, whenever cost effective over the lifetime of the roof, when constructing new roofs or replacing old ones at DOE facilities. With cool roofs, these federal buildings will consume less energy, offset additional carbon emissions, and save taxpayers money.” Read more at Energy.gov
View Chu’s presentation on the benefits of cool roofs below.