During the summer months, the surface of a home’s traditional, black roof can be 50 degrees hotter than the outside temperature. These sunny days do not only increase your roof’s temperature but raises the temperature inside your home as well, increasing your air conditioning and energy costs. So how can homeowners cool off their roof during the hot days of summer?
A cool roof, according to the U.S Department of Energy, is “one that has been designed to reflect more sunlight and absorb less heat than a standard roof.” Cool roofs are able to do so through special material such as paint, shingles, tiles, or other roofing materials that are highly reflective. To understand the concept of a cool roof, think about why you would wear a light colored shirt on a hot day versus a darker colored shirt. A lighter color shirt absorbs less heat than a darker shirt thus keeping you cooler. The same works with a roof. Cool roofs can be applied to residential or commercial roofing projects and are not as expensive as some may initially think, especially if you are already in need of roof replacement.
Benefits of a Cool Roof
There are many benefits to a cool roof for the inside occupants and for the environment:
- Decrease air conditioning use which in turn lowers the cost of your energy bills/
- For spaces that do not use air conditioning (garages, car ports, etc.) lower temperatures, increasing overall comfort.
- Overall decrease in roof temperature, which will in most cases, extend the lifetime of your roof.
- Lower urban heat island effect. According to Wikipedia, an urban heat island (UHI) is an urban area or metropolitan area that is significantly warmer than its surrounding rural areas due to human activities.
- Reduction in emissions like carbon dioxide, sulfur dioxide, and mercury from buildings that use excessive energy to cool their interiors.
- Decrease peak electricity demand.
- Rebates and incentives for owners.
- Extension of roof lifespan.
- HVAC downsizing.
Cost of a Cool Roof
The surface of a roof is what makes it a cool roof or not. Any roof, existing or new, can become a cool roof by its surface material. With that being said, if your roof is need of replacement, the cost of a cool roof will be much less expensive than if you a converting an existing roof, with no issues, to a cool roof.
When considering a cool roof, factor in the following items:
- Your climate
- Your current roof’s insulation
- Your current roof’s type (tile, shingle, etc.)
- Your cooling and heating systems efficiency
Cool roofs do not necessarily save money in colder climates. In colder climates during the winter months they could potentially increase your energy costs because they do not allow your home to benefit from heat gains.
If you are considering installing a new cool roof, use this Cool Roof Calculator to estimate how much you could possibly save on energy in your home. Also check for rebates and tax credits offered in your area.
Cool roof expenses are much like any other roofs if installing on a new project. Majority of costs include materials and labor, sometimes specialized, and ongoing maintenance like repair, coating, and cleaning.
Types of Cool Roofs
There are a number of different types of cool roofs. Choose a type of cool roof based on it’s slope, your budget, and the style of your home.
Paint, glazes, and waterproofings can often turn roofing tile or metal roofs into cool roofing materials unlike shingles. It is best to purchase cool asphalt shingles that granules are better suited for solar reflections. Other common cool roof materials include single-ply membranes, modified bitumen sheet membranes, and spray polyurethane foam.
Roofs can reach temperatures as high as 150°F higher during the summer months in hot climates. A cool roof can assist lower your home’s energy costs during this time of year by lowering that temperature by as much as 50°F.
EMA Construction’s qualified roofers are here to advise homeowners on the best roofs for their individual homes. If you have any questions relating to cool roofs or other alternatives, please contact us.