Painting the City White: Over a Million Square Feet of White Roofs

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With a soft, squishy thrust of a roller, the CoolRoofs program painted its millionth square foot of white roof on top of a housing project in the Bronx Wednesday. To celebrate the coverage, sporting an orange T-shirt just like the other volunteers, Mayor Michael Bloomberg helped roll that patch into place.

CoolRoofs is one of several programs that is painting black roofs white, and they hope it will spark a city-wide trend among building owners.

“If we can serve as a model and landlords throughout this city say 'Wait a second, if I paint my roof I'm gonna reduce my energy cost by 25 percent' next time you get your ConEd bill say 'Hey wait, maybe I should do it,'” Bloomberg said.

Building owners with white roofs need less energy for air conditioning and can save up to 50 percent on their electricity bills, according to CoolRoofs. The cost is $2 to $4 per square foot, including labor and the savings can pay for the job in as little as two years.

White roofs aren’t new. People have been white washing buildings for centuries in hot climates. Many New York roofs are already white. But now with a greater emphasis on cutting green house gas emissions white roofs have become a national cause, lead by Secretary of Energy Steven Chu.

Research has predicted that white roofs can lead to lower green house gas emissions and other environmental benefits. By painting the remaining 500 million dark roofs in New York City white, the urban heat island effect could be reduced by 33 percent; lowering temperatures by 2 degrees Fahrenheit.

CoolRoofs is a project of NYC Service, the city’s volunteer agency. Over 1,500 volunteers painted 105 roofs this summer as part of the wider effort to reduce the city’s green house gas emissions by 30 percent by 2030.

Diane Billings-Burford, chief service officer for NYC Service says next year they want to be more strategic. “Not only with our high goal of coating more rooftop, but really using the information from ConEd and the information from a wonderful team of people at Columbia [University] who are helping us to evaluate the impact this initiative really has,” Burford said. 

Next summer CoolRoofs will target neighborhoods to see if temperatures go down when the roofs go white. And energy use data will be collected from buildings with white roofs to see if electricity bills also go down.