How Much Cooler Is A White Roof

The white powder actually reflects away much of the sunlight so the dark roof underneath cannot absorb heat and melt the snow.

How much cooler is a white roof. Dark roofs may have a small snow melt effect but not a sizeable one. Atmosphere a white roof should act like a natural anti warming device while also reducing your energy costs by keeping your house cool in the summer. Standard or dark roofs can reach temperatures of 150 f or more in the summer sun. Switching to a white roof can actually reduce energy use by about 20 percent in hot sunny weather according to the lawrence berkeley national laboratory heat island.

In cooler climates think detroit or toronto the issue is less straightforward. Unless routine maintenance and power washing is completed a white roof will often dull and look. White roofs will stay white. A cool roof under the same conditions could stay more than 50 f cooler and save energy and money by using less air conditioning.

The question is by just how much. Turns out painting your roof white would be. So although your building may be cooler it s not doing much to decrease global warming. Such a roof can be reasonably expected to be some 50 to 60 degrees cooler than a dark color asphalt shingles roof.

During the maximum internal temperature increase hours of 7 00am 5 00pm a white roof is 6 97 cooler more energy efficient than a non white roof. Cool roofs can be made of a highly reflective type of paint a sheet covering or highly reflective tiles or shingles. Some scientists say white roofs can increase heating costs more than they save on a c costs. They built test houses white roof vs black roof.

In fact a high end kynar 500 white metal roof is energy star rated and classified as a cool roof by the cool roof rating council. While white roofs may shave electric bills in hot summer months studies suggest they increase winter heating bills. However and here is the big kicker a properly ventilated attic space let me say that again properly ventilated was a 2 degree average difference. Similarly if your roof experiences winter problems like ice dams your roof color probably isn t the primary culprit.

What they found was surface temprature hand to shingle was approximately 20 degrees warmer if black. False white roofs attract and retain dirt easily which quickly diminishes some of the positive aspects of the membrane.