A synergistic approach to high-performance energy savings
Raised seam metal roofing is used for reducing cooling/heating loads on new construction and on retrofit roofing applications in the commercial, industrial, architectural, institutional, and residential construction markets. Depending on the choice of finishes and colors, this family of roofing products has solar reflectance and infrared emittance properties conducive to lowering cooling and heating energy usage, lowering peak energy demand in buildings, and mitigating the urban heat island effect. The roof surface layer absorbs partial solar radiation, and which becomes the net heat flux into the roof. The total solar radiation is reflected and part of it becomes re-emitted energy once it has contacted the roof surface layer. The combination of the re-emitted energy and reflected radiation on the roof surface layer creates convection.
A measure of a material's reflectivity is termed "albedo". Reflective roofs incorporate both high solar reflectance, or albedo, and high thermal emittance. Solar reflectance is a measure of the percentage of solar radiation that is reflected when it strikes the roof surface. Thermal emittance, or emissivity, is the percentage of energy a roof can radiate away after it is absorbed.
Standing seam metal roofing products are included on the EPA's Energy Star Roof Products directory. The EPA estimates that reflective roofs can save up to 40% cooling energy on homes and buildings. Florida Power and Light (FPL) has also recognized the sustainable energy-efficiency of metal roofing in a cooperative program involving Florida Solar Energy Center and Habitat for Humanity. FPL found that a painted metal roof could save a homeowner about 23% annually in cooling costs compared to a dark colored traditional shingle roof. (Florida Power and Light, Februrary 5, 2001 press release)
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