Looking for a way to lower your air conditioning bill or avoid installing an air conditioning system entirely? Well, you can lighten up – your roof that is. According to the Cool Roof Rating Council, a cool roof can save home and building owners between 7% and 15% on their cooling energy costs. And since cool roof materials cost about the same or even less than other standard roofing materials, it makes sense to install cool roofing if you reside in a warm climate.

This cool roof features light colored metal roofing materials. Photo courtesy of the U.S. EPA.

What a Cool Roof Can Do

Sunlight makes roofs very hot and that roof heat is transferred inside the structure, whether a home or a commercial building. But a cool roof reflects the heat of the sun and sends it right back into the atmosphere, keeping your roof surface (and the interior of the building) nice and cool.

In roofing, two material properties – solar reflectance and thermal emittance – measure the coolness of a roof’s surface. Solar reflectance is defined as how much the roof can reflect solar heat. Thermal emittance determines how well the roof cools itself by releasing thermal radiation. The higher the solar reflectance and thermal emittance values, the cooler the roof remains.

The California Energy Commission estimates that during the summer, the temperature of a traditional roof reaches between 150 and 190 degrees F, while a cool roof temperature hits between 100 to 120 degrees F. Cool roofing works by reflecting sunlight (solar reflectance) and releasing heat (thermal emittance) so the roof stays much cooler. With less roof heat getting into your home or building, your air conditioning doesn’t have to work as hard, if at all.

Cool Roof Characteristics

As the U.S. Department of Energy points out, you can make a new or existing roofing system cool by using the proper cool roof coating for your type of roofing. In general, a cool roof is made of highly reflective shingles or tiles, a sheet covering, or highly reflective paint. Here are some ways the Roofing Annex can make your existing roof cool:

• Shingle Roofs – Shingle manufacturers make cool asphalt shingles, which are coated with special granules that reflect the sun. For other roof shingles, like wood, fiberglass, metals, or polymers, the Roofing Annex can arrange for a special reflective coating to be added either by the manufacturer or by our roofing contractors when your roof system is being installed.
• Tile Roofs – Tile roofing is naturally reflective, especially if the slate, clay, or concrete tiles are a light color. Customized color coatings are available to turn a dark tile roof into a cool one.
• Metal Roofs – Unpainted metal roofs can be painted a light color, or a cool reflective coating can be applied.

Low sloped roofs, like those typically found on commercial buildings or residential outbuildings, also can be made cool through the application of special coatings. These coatings, which have the texture of a thick paint, contain reflective pigments that reflect sunlight. They are sprayed, rolled, or brushed on to existing roofs.

Going Cool

If you’re interested in learning more about cool roofing and whether it’s right for your home, get in touch with us. The Roofing Annex has the knowledge and expertise to guide you in getting the most out of your roofing system.