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It’s Easy Being Green: White Is the New Green

Using white and other light colors on roofs and roads can help save on energy costs and fight global warming.

Energy Secretary Steven Chu has mandated that all Department of Energy buildings have white roofs to combat urban heat islands and reduce energy use. (AP/J. Scott Applewhite)
Energy Secretary Steven Chu has mandated that all Department of Energy buildings have white roofs to combat urban heat islands and reduce energy use. (AP/J. Scott Applewhite)

Read more articles from the "It’s Easy Being Green" series

Forging ahead into a more sustainable future sometimes involves wrapping your head around some pretty esoteric, complicated, and scientifically advanced information. Hydrogen fuel cells, ocean thermal energy conversion, photovoltaic energy, and a host of other polysyllabic Latinate terms often necessitate complex descriptions in order for the average person to make heads or tails of them. Fortunately, one of the most significant ways we can mitigate global warming is also one of the simplest to understand. Going green means going white.

The concept is simple: Dark colors absorb heat, while light colors reflect it. It’s an idea that has helped stop Peruvian glaciers from melting, and it will help keep cities from suffering ever-worsening greenhouse effects. The black roads and dark pavements that blanket our cities have helped create the phenomenon known as the urban heat island. The term refers to the fact that cities are significantly hotter than outlying suburban and rural areas receiving the same amount of sunshine due to their high concentration of dark-paved roads, black-colored roofs, and lack of vegetation.

Urban heat island mitigation, or UHIM, entails paving roads with cooler-colored materials (such as concrete rather than asphalt), making roofs white, and planting a lot more trees in urban spaces. ClimateProgress.org notes that UHIM will green our cities in many different ways, by increasing the earth’s reflectivity and thereby slowing global warming, reducing local temperatures in hot cities, reducing carbon emissions, improving public health, saving money on energy costs, and creating hundreds of thousands of jobs if applied on a large scale. Switching 85 percent of buildings’ roofs to cool colors, for example, will deliver $735 million in annual savings, all without requiring highly skilled labor or expensive, uncommon materials.

Secretary of Energy Steven Chu has mandated that all Department of Energy buildings have white roofs in order to show how to combat urban heat islands. He has touted the benefits of white roofs far and wide, frequently citing a calculation finding that if the world’s 100 largest and hottest cities switched to white roofs and light-colored cement pavement, the net effect would be the equivalent of taking all the world’s automobiles off the streets for 11 years.

Individual homeowners don’t have to wait for federal action to cool their abodes. Changing your home’s roof to a more reflective color is one of the easiest and most cost-effective green modifications you can make to your house. It can reduce energy use by 20 percent during hot, sunny weather, according to the Lawrence Berkeley National Laboratory Heat Island Group.

If you’re thinking of putting up new roofing, go with white material. It costs no more than black roofing, so if you choose white roofing materials the money you won’t spend on air conditioning your house will be 100 percent savings. If you’re not in the market for a new roof, yet are still interested in cooling your home, consider buying white roof coating. The cost runs anywhere from $0.50 to $1 per square foot, and in addition to cutting down on your energy bills it will help extend your roof’s life.

Not all green re-engineering projects have to be as difficult to understand as an advanced lecture on organic chemistry. Cooling our roofs and streets by switching to shades of white shows that sometimes simple solutions have the greatest effect.

Read more articles from the "It’s Easy Being Green" series

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