BY Aline Reynolds
New York City just reached a milestone in coating its rooftops, including ones in Lower Manhattan, which can actually lead to a drop in outside temperatures.
The Department of Buildings just finished coating one million square feet of rooftops in an effort to lower cooling costs, energy usage and greenhouse gas emissions.
Downtown buildings whose roofs were painted include the D.O.B.’s headquarters at 280 Broadway; University Settlement, at 184 Eldridge Street; and The New School, at 66 West 12th Street, among others.
A white roof can reduce air conditioning costs by up to 50 percent in a one-story building and 25 percent in a two-story building, and by up to 10 percent in a five-story building, according to a study conducted by the D.O.B.
Groups of volunteers from Green City Force and elsewhere coat the roofs in groups.
“It was super-fun,” said CoolRoofs volunteer Cam Climaco, who helped paint the Henry Street settlement rooftop in mid-September. It’s not like hard work, and you feel really good about it at the end of the day,” she said.
The experience, she added, has inspired her to become more proactive in the Downtown community.
The city is five to seven degrees warmer than the nearby suburban and rural areas in the tri-state area due largely to the impermeable surfaces of its rooftops and streets. Cooling all eligible dark rooftops citywide could actually reduce the city’s air temperatures by about one degree.
In the meantime, white roofs in a concentrated area cools down the nearby sidewalks. “You can actually feel it if you’re walking on the street,” said Danielle Grillo, executive director of community partnership at the D.O.B.
A roof with white, reflective coating soaks up 80 percent less heat than traditional dark-colored roofs. As a result, rooftop temperatures drop by up to 60 degrees on hot days, and typically last five to ten years longer without as much heat-related stress.
“The decrease in energy usage from cool roofs will also help reduce the likelihood of blackouts and brownouts, as the strain on the power grid during times of peak demand will be lessened,” according to the D.O.B.
More than 1,500 volunteers and nearly 20 companies have taken part in the program since its induction in May.
“We are tapping into the incredible spirit of volunteerism in our city and harnessing that energy to tackle some of the challenges government can’t solve on its own and that includes reducing the city’s carbon footprint,” said Mayor Michael Bloomberg in a statement.
Nearly all buildings in the city are eligible for the service, so long as their roofs have a flat surface, according to Danielle Grillo, executive director of community partnership at the D.O.B. Most of the coated buildings thus far house government entities and nonprofits.
The program is part of PlaNYC 2030, the city’s comprehensive sustainability plan to reduce greenhouse gas emissions by 30 percent by the year 2030.
“By simply applying a reflective, white coating, we can reduce rooftop temperature by up to 60 degrees, which translates into reduced cooling costs and reduced carbon emissions – a primary goal of PlaNYC,” said Bloomberg.
In return for the service, the occupants of the building must submit their energy bills to the Department of Labor for data-collecting purposes.
