"Be Cool"

Cool Metal Roofs Provide Long-Term Energy and Durability Benefits for Buildings

By: Mark A. Thimons

via: http://www.metalmag.com/cool-roofing/be-cool.aspx

In today's tough economic climate, the decision about which roofing material to use can hinge as much on the material's sustainable attributes-such as energy efficiency-as on its appearance and cost. Because a roof can have a significant impact on the energy use in a building, the material selection is an important decision. Increasingly, building designers, engineers and owners are turning to cool metal roofing products to meet their demands for durability, energy efficiency and cost-effectiveness as they look for ways to enhance their investment.

Cool roofs have radiative properties that reduce surface temperature, minimize the amount of heat transferred into the living space below and reduce the heat released from the surface to the ambient air. The energy efficiency benefits of a cool roof are determined primarily by two properties: total solar reflectance and infrared emittance. Cool metal roofing products comprise unpainted metal, prepainted metal and granular-coated metal for steep-slope and low-slope applications. They are part of an interdependent system of exterior roofing surfaces, substrates, underlayments, configurations, ventilation and insulation.

More information on cool metal roof's can be found by following this link http://www.metalmag.com/cool-roofing/be-cool.aspx including diagrams that explain solar reflectance and infrared emittance.