The Cost of a Cool Roof
Apr 12, 2017
A cool roof is a roofing system that is built to reflect dangerous solar UV and infrared rays away from one’s home. This works counter to inefficient roofing systems which trap heat and send their surface temperatures up by many degrees, poorly limiting the heat flow coming into the house.
At least 90 percent of America’s residential roofs are dark-colored. The darker a roof is, the more propensity for heat-trapping it has, often reaching 100 degrees Fahrenheit on top of the existing temperature in a full sun’s wake. That’s ridiculous and brings with it many complications to the roof itself as well as the rest of the home in various ways if not treated or replaced.
Roofs with inefficient cooling techniques have three negative effects:
You can either apply special roofing material on top of your existing roof to make it cooler or install a new roof with an inherent cooling system altogether. Either way, you can potentially bring down thermal absorption by as much as 50 percent.
The kind of solutions appropriate for your existing roof depends on the slope and height of it. Check out this article for more information on the right application to go with.
When it comes to the solar heat received, roofs work by reflecting the sun’s rays outward (solar reflectance), radiating some of the ones it absorbed (thermal emittance), and letting some of them pass through into the home (thermal conduction). Cool roofs do this well by reflecting the rays as much as possible, emitting or releasing the heat as much as possible, and absorbing it as little as possible.
Asphalt, the most commonly used roofing material in the United States, is only 6 to 26 percent effective against solar radiation. A good replacement would have to be white vinyl due to its good reflective properties. About 80 percent of the sun’s rays can be reflected and release 70 percent of the absorbed radiation. The best possible version of vinyl would have to be thermoplastic white vinyl roofing.
Solar reflective coatings don’t just make your home’s indoor climate comfortable, they extend the life of your roof, especially if it is particularly prone to deformation from excessive sunlight. Coating applications run in the thousands, so you’ll be able to find something that’s just right for your home. The most popular of these coatings are metal, single-ply, BUR systems, and modified bitumen. And they don’t require a removal or expensive installation costs.
For years, cool roofs used to come in strictly bright colors to optimize the heat limiting properties of the product. But now, thanks to the advancement of technology, cool roofs can come in any dark color without taking a significant toll on the product’s heat deterring qualities.