A study that finds that if cool roofs were installed on 50 percent of existing roof surfaces for residential, commercial, and government and public use buildings in southern California, it could save up to 1.6 million megawatt hours of electricity annually, enough energy to power more than 127,000 homes in California and save residents up to $211 million in energy costs each year based on 2012 rates. The energy savings would cut carbon pollution by 465,000 metric tons annually.