New York City Roof Study Shows Drastic Cooling with White Surfaces


A New York City roof covered in a white synthetic membrane was on average 43 degrees F cooler than surrounding black tar and asphalt roofs during times of peak heat last summer, according to a study by scientists from Columbia University and NASA.

On the hottest day of the summer — July 22, 2011, when the city set a record for electricity usage during a heat wave — the dark surfaces of some city roofs reached 170 degrees F, while temperatures on the white test roof peaked at less than 130 degrees F.

The city’s CoolRoofs initiative is working to install “living roofs” with plants and to convert many tar and asphalt roofs to a white color using membranes or white paint. The goal, the city says, is to help reduce the urban “heat island” effect, which can boost temperatures by 5 to 7 degrees F, especially at night.

Lowering the heat island effect would reduce demand for air conditioning and cut illnesses and deaths during heat waves. Converting roofs to white is cheaper than planting “living roofs,” the researchers noted. “Bright is the new black,” said Stuart Gaffin, a Columbia scientist and lead author of the study, which was published in the journal Environmental Research Letters.

Article appearing courtesy Yale Environment 360.

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Yale Environment 360 is an online magazine offering opinion, analysis, reporting and debate on global environmental issues. We feature original articles by scientists, journalists, environmentalists, academics, policy makers, and business people, as well as multimedia content and a daily digest of major environmental news. Yale Environment 360 is published by the Yale School of Forestry & Environmental Studies and Yale University. We are funded in part by the Gordon and Betty Moore Foundation and by the John D. and Catherine T. MacArthur Foundation. The opinions and views expressed in Yale Environment 360 are those of the authors and not of the Yale School of Forestry & Environmental Studies or of Yale University.

1 Comment

  1. White roofs and walls are used in Mediterranean area from centuries.

    Sorry but this post is not so innovative or revolutionary. Some interesting studies has been done on Titanium oxide (that is one of the components of the whites paint) as catalyzer for smog reduction.