Green roofs and cool roofs (i.e., those designed to deflect heat) make sense in different climates for different reasons. In cities built close to natural bodies of water, for example, a green roof can help to filter storm water runoff before it becomes a source of pollution. And in areas where AC, rather than heating, claims the lion’s share of the utility bill, such roofs can save home and building owners money. Southern California is the case in point: according to a recent study from the Natural Resources Defense Council (NRDC), installing green roofs and cool roofs in southern California could save consumers more than $211 million in energy bills while reducing the stormwater runoff that pollutes the area’s beaches.
The new study, entitled “Looking Up: How Green Roofs and Cool Roofs Can Reduce Energy Use, Address Climate Change, and Protect Water Resources in Southern California“[PDF], was conducted in conjunction with the Emmett Center on Climate Change and the Environment at UCLA School of Law. It found that if green roofs or cool roofs were installed on 50 percent of the existing roof surfaces for residential, commercial, government and public-use buildings in southern California, the state could save up to 1.6 million megawatt hours of electricity on an annual basis.
To put that number in perspective, that’s enough juice to keep the lights on for more than 127,000 California homes, and the equivalent of taking 91,000 cars off the road each year–enough to cut the notoriously smoggy region’s carbon pollution by 465,000 metric tons on an annual basis.
“The scale of these benefits is truly impressive, and justifies a much more aggressive set of policies and incentives to help advance the adoption of green roofs and cool roofs in our region,” said Cara Horowitz, the Andrew Sabin Family Foundation executive director of the Emmett Center on Climate Change and the Environment at UCLA School of Law, in a statement. She goes on to note that if Los Angeles and other southern California cities offered better incentives for residential and commercial building owners to install green roofs and cool roofs, the region would create healthier, more sustainable neighborhoods while saving some cash in the process.
Given Los Angeles‘s recent focus on energy efficiency, it seems like that one city, at least, may heed that opportunity.