Spec Wizard

Overview | Urban Heat Island Effect | Facts and Benefits | Glossary | Cool Metal Roofing Data Sheet

What is cool metal roofing?

Cool metal roofing is a family of sustainable and energy efficient roofing products. It is available in a wide variety of colors and profiles for steep-slope and low-slope applications. Cool metal roofing products are part of an interdependent system of exterior roofing surfaces, substrates, underlayments, configurations, ventilation, and insulation.

A building's cooling and heating costs can be effectively reduced by insulation under the roof surface. Adding increasing amounts of insulation is not always the best way to save energy. As part of total system design, a cool metal roof can be an economical method for better energy efficiency. This family of roofing can achieve solar reflectance of over 70%. Reflected solar energy allows the roof surface to remain cooler, which means less heat is transferred into the building.

The infrared emittance of a roof is a measure of absorbed solar radiation that is reemitted from the roof surface to the sky. Emittance of metal roofing varies with the surface finish. Emittance of painted metal roofing can be as high as 90%.

Where annual cooling loads dominate, a highly reflective and highly emissive painted metal roof is optimal for reducing energy consumption. Where annual heating loads dominate, an unpainted metal roof is more desirable because of its low infrared emittance.

Net Heat Flux into Roof