Roofs Reflect Better Savings
A version of this article appears in the July/August 2001 issue of Home Energy Magazine.
July 01, 2001
Reflective roofing represents one of the most significant energy-saving options available to homeowners and builders.
Dramatic savings in cooling energy are possible with highly reflective roof systems. But,exactly how dramatic? That’s the question we,at the Florida Solar Energy Center,sought to answer when we measured the cooling performance of different materials during realistic weather conditions. Heat gain through the roof and attic exerts a powerful influence on cooling energy use in Florida homes. Unshaded residential roofs are heated by solar radiation, causing high afternoon attic air temperatures. This effect is due to increased ceiling heat transfer as well as heat gains to the duct systems,which are typically located in the attic space (see Figure 1). We monitored the impact of roofing materials on cooling energy by monitoring seven side-by-side 1,144 ft2 Habitat for Humanity houses in Ft. Myers, Florida. Six houses had identical floor plans, orientation, and R-19 ceiling insulation, but different roofing systems designed to reduce attic heat gain. The seventh house had an unvented attic with insulation on the underside of the roof deck rather than on the ceiling. The houses were completed in June 2000, and then extensively tested to ensure that ...
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