What is a Cool Roof?
A cool roof is a roof that strongly reflects sunlight and also cools itself by efficiently reflecting the sun’s heat to its surroundings. The roof remains cooler and reduces the amount of heat going down into the building below. This keeps the building cooler and provides a more constant temperature. For air conditioned homes and buildings, this means the air conditioner does not have to work as hard, which can save you money in electric bills. It is the same idea as choosing 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 does not have to be white. There are many “cool color” products that use darker colors 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, with 1 being the most reflective.
What are the Benefits of a Cool Roof?
A cool roof can significantly reduce your cooling energy costs and increase your comfort by reducing temperature fluctuations inside your home or business. Average energy savings can range from 7 to 15 percent of total cooling costs. Some other benefits include:
- Reducing your utility bills
- Increasing comfort
- Decreasing the size of and prolonging the life of your air conditioning system
- Lowering roof maintenance costs and extending roof life
- Avoiding re-roofing costs and reducing solid waste
- Assisting your home in meeting building codes
- Mitigating your community’s Urban Heat Island Effect
- Maintaining aesthetics with a roof that performs and looks good
- Receiving utility rebates (in some locations)
SOURCE: Cool Roof Rating Council www.coolroofs.org
Here is the difference a Duro-Last PVC Roof can make:
Here is the difference a Gerard Stone Coated Steel Cool Roof can make:
Should You Paint Your Roof White to Save Energy?
Not long ago, U.S. Energy Secretary Steven Chu suggested that painting your roof white is one way to fight global warming. The white paint would reflect sunlight, keeping your home cooler and reducing the need for carbon-fueled electricity.
But painting your roof white is not a practical solution for everyone. Many subdivisions would not allow it, for one thing, and it could end up costing more in the winter to heat your home. One answer can be colored metal roofs in light, or cool, colors that will reflect light but still be a more traditional color that fits in with your neighborhood.
Studies show that a metal roof can save up to 25 percent in cooling costs when compared to a typical dark gray asphalt shingle roof. When installed with an air ventillation gap above the sheathing, a metal roof can also cut your winter heating costs. And while metal roofs can cost more initially, they will probably never need to be replaced. An asphalt roof, on the other hand, should be replaced about every 15 to 20 years. A metal roof can also increase the resale value of your home.
Today’s metal roofing looks more like traditional roofing materials. You can choose from styles that look like asphalt shingle, cedar shake, clay tiles or slate. They come in a wide variety of colors, both dark and light, and come with a special metallic coating that prevents rust and is sturdy enough to walk on. Adding a protective sheathing underneath quiets the sound of rain, hail or other noises. Not only is a metal roof energy efficient, it will add to fire resistance for your home.
Metal roofs are more resistant to hail damage than a traditional asphalt roof, a benefit for homeowners in the Jacksonville region. Some insurance companies will provide rate reductions for installing a metal roof. Plus, many styles have been tested to withstand hurricane force winds. Contrary to popular belief, a metal roof is not more susceptible to being struck by lightening than any other roofing material.