Paint It White
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:
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’
