What is it?

• A white roof is a simple, innovative way to keep your building cool and your energy costs down. A roof doesn't necessarily have to be painted white to be considered a white roof. You can use any reflective color or reflective materials available at home improvement stores.


• Dark roofs can reach up to 180°F on sunny, windless days, increasing summer cooling costs. A white roof can reduce temperatures up to 90°F.

Why are they useful?

Light-colored roofing materials tend to have a longer service life. The constant heating and cooling of a roof causes its materials to expand and contract - causing a wear and tear that has an impact on the life of a roof. Light-colored roofs last longer simply because they don't expand and contract as much as a traditional, dark-colored roof.

What can they do for New York City?

A white roof can offset the “heat-island effect” - a phenomenon that occurs in densely built cities where the average temperature is up to 10 degrees hotter than surrounding areas. Dark roofs contribute to the heat-island effect by absorbing energy from the sun. A white roof offsets this effect by reflecting the sun's rays, reducing the heat gain on the earth's surface.

* Derived using the New York State Energy Research and Development Authority’s report “Mitigating New York City’s Heat Island with Urban Forestry, Living Roofs, and Light Surfaces.”