Paint It White

White Rooftops Bermuda

Summer is nearly upon us in the Northern Hemisphere and for city dwellers and suburbanites (like my family) summer brings the 'Heat Island Effect'. The sub/urban Heat Island is the result of acres of black-tar roofs and dark asphalt absorbing solar energy during the day and radiating that heat out late into the night. It turns out there is a simple way to turn off the Heat Island - Paint it White. White (or light-colored) roofs and pavement can reduce the heat island effect by 5 to 7 degrees Fahrenheit in the summer!

Going further, researchers at the Concordia University Heat Island Group in Montreal estimate that painting 1% of the world’s urban surfaces white (rooftops and pavement) could reduce CO2 emissions by 130 gigatons over the next 50-100 years! In 2011, global CO2 emissions from fossil fuel combustion reached 31.5 gigatons. Their study on The long-term effect of increasing the albedo of urban areas, while academically named, helps quantify the big difference white roofs can make.

Just a few years ago, we replaced our roof with a 'cool-roof' and have enjoyed a cooler home each summer since then. While our roof isn't white it does have a high Solar Reflectance Index and an Energy Star rating. It's nice to know we're slightly ahead of the curve once in a while.

Apologies to the Rolling Stones, but I'm pretty sure they weren't talking about shingles.

More Info:

Heat Island Effect

Bright Is The New Black: New York Roofs Go Cool

The long-term effect of increasing the albedo of urban areas

Cool Roofs and Cool Pavements Toolkit

How Painting Roofs White Can Help ‘Turn Off The World For A Year’

Cool Roof: Pro-Panel vs. Asphalt Shingle