Architects and contractors are looking for and demanding roofing products that can provide LEED (Leadership in Energy and Environmental Design) points for sustainable building projects.
In order to qualify for this credit, the product selected had to be Energy Star-compliant and meet a minimum emissivity of 0.9 when tested in accordance with ASTM E408. As explained on www.coolmetalroofing.org, "Emissivity is a measure of the thermal emittance of a surface ... Values range between 0 and 1. Emissivity may be thought of as the ability of a material to emit heat (via infrared radiation) to the surrounding atmosphere. Higher numbers indicate faster heat transfer. "