Dispatch from SSC Intern Barbara Summers
Studies have shown that an easy way to reduce energy costs, particularly in warmer climates, is the installation of a light colored or white roof. A white roof can cost as little as 15 percent more than its dark counterpart depending on the materials used, but it can reduce air-conditioning costs by 20 percent or more in hot, sunny climates. Solar energy delivers both light and heat, and the heat from sunlight is readily absorbed by dark colors. Lighter colors, however, reflect back a sizable fraction of the radiation, helping to keep a building cooler. If all of the world’s roofs were turned into white roofs over the next 20 years, that would mean saving 24 billion metric tons of carbon dioxide emissions. That is equivalent to what the entire world emitted last year.
Historically, white or light colored roofs were standard in the southern and western United States, but as Joe Reilly, the president of American Rooftile Coatings stated, “Relative newcomers to the West and South brought a lot of habits and products from the Northeast”, including darker types of roofing. He also said that the switch back to these traditional light colored building strategies is only common sense.
This type of roofing may not be the most efficient one in colder climates, where heating costs outweigh the air-conditioning savings. But for most types of construction, experts say, light roofs yield significant net benefits as far north as New York or Chicago. Although those cities have cold winters, they are heat islands in the summer. Some states such as California, Florida and Georgia have already adopted building codes that encourage white-roof installations for commercial buildings.
It may actually be feasible to replace most roofs within a 20 year period because most roofs, whether tile or asphalt-shingle, have a life span of only 20 to 25 years. So if you are going to replace your roof, why not invest in a light colored roof and reap the benefits and energy savings? Although white-roofs may not be as aesthetically pleasing, there are other lighter shades such as light grays or beige that can still provide significant savings.
For more information on white roofs click here.