What is a Cool Roof?
A cool roof is one that strongly reflects sunlight and also cools itself by efficiently emitting radiation to its surroundings. The roof literally stays cooler and reduces the amount of heat conducted to the building below. If a builder does not have air conditioning, this keeps the building cooler and a more constant temperature. If a building has air conditioning, the equipment does not have to work as hard. Imagine wearing a white or a black T-shirt on a hot day. By wearing the white T-shirt you will remain cooler than if you wore a black T-shirt because it reflects more sunlight and absorbs less heat. Cool roofs, like a white T-shirt, keep the internal temperature of the building lower.
However, a cool roof need not be white. There are many cool color products which use darker-colored pigments that are highly reflective in the near infrared (non-visible) portion of the solar spectrum. Because a white roof strongly reflects both visible and near infrared sunlight, a white roof will typically be cooler than a cool colored roof.
The two basic characteristics that determine the “coolness” of a roof are solar reflectance (SR) and thermal emittance (TE). Both properties are rated on a scale from 0 to 1, where 1 is the most reflective or emissive.
What are the Benefits of a Cool Roof?
A cool roof can significantly reduce your cooling energy costs and increase your comfort level by reducing temperature fluctuations inside your building. Average energy savings from having a white roof range from 7%-15% of total cooling costs, but only waterproofing & cooling coating COOL-R with SRI 107 can offer you savings reaching 40%.
Some other benefits include:
• Reducing your utility bills associated with air conditioning
• Increasing occupant comfort and avoid installing an air conditioner where there isn’t already one
• Decreasing the size and prolong the life of your air conditioning system
• Lowering roof maintenance costs and extend roof life, avoiding reroofing costs and reducing solid waste
• Assist your home in meeting building codes
• Mitigate your community’s Urban Heat Island Effect
• Maintain aesthetics with a roof that performs and looks good
• Receive utility rebates (in some locations)
• HVAC system design savings for new investments
• Additional LEED points given by Green Building Council