Yesterday, U.S. Department of Energy Secretary Steven Chu announced that he would be increasing the number of buildings with white roofs for DOE and other buildings belonging to the government. This is part of the promise by the Federal government to reduce their emissions by 28 percent by 2020. White roofs are so effective because they reflect the sun's rays rather than absorbing them, thus cooling the inside of the house. In cities, it can also help cut down on the urban heat island effect. This effect occurs in cities where the landscape is dominated by dark roofs and pavement, and it creates a rise in temperature comparative to the surrounding, non-city landscape. If the transition was made to more and more white roofs our cooling costs could be reduced tremendously. The DOE itself has claimed to have already installed more than two million square feet of white roofs, claiming a savings of $500,000 a year in energy consumption. To take this a step further, in the video below, Steven Chu explains how if we were to retrofit all existing buildings with white roofs, and replace dark paving materials with light, it would be comparable to removing all automobiles on the planet for 11 years in terms of carbon emissions. Check it out: