What can I do to my roof to save on energy costs?

New homes in need of roofs.
By covering your house with a good, energy-efficient roof, you can save a lot of money down the road.
­AP Photo/Ross D. Franklin

­Did you know that nearly half of the money you spend on utility bills goes toward heating and cooling your home [source: Federal Trade Commission]? In many American homes, energy costs are literally going through the roof. Your roof is your first -- and best -- defense against the summer heat and the winter chill. A low-efficiency, poorly insulated roof can let in too much heat in the summer, leaving you with huge air conditioning bills. It can also let off too much warmth in the winter, leading to astronomical heating costs.

Spending a little bit of money on a good roof now can save you a lot on heating and cooling bills in the long run. An energy-efficient roof not only protects you from the elements, but it also keeps your home cooler in the summer and warmer in the winter. Energy-efficient materials are also able to withstand the constant bombardment of ultraviolet (UV) radiation from the sun, extending the life of your roof.


­The most energy-efficient roofing products have a high solar reflectance, meaning that they reflect the sun's energy back into the environment, rather than absorbing it. Reflective roofs can reduce the temperature on the surface of the roof by as much as 30 percent -- which means that less heat gets into your home [source: Energy Star]. The most energy-efficient roofs also have high emittance, which means they're efficient at releasing any solar heat they have absorbed.

Adding insulation can further increase your roof's energy efficiency. R-value measures the ability of insulation to resist the transfer of heat. In colder climates, insulation materials that have a higher R-value can help trap heat inside the home and lower home heating costs.

Depending on where you live, you might get a financial incentive for making your roof -- and home -- more energy efficient. In California, for example, residents who increase the thermal value of their home's insulation get rewarded in the form of tax rebates.


Picking the Right Roof

When choosing a roof, look for products that carry the government's Energy Star label, because they can save you a lot on energy costs. The government created the Energy Star program to help promote the use of energy-efficient products. Only roofing products that are highly reflective are given the Energy Star label. These roofs can reflect enough of the sun's rays to lower the temperature on the surface of your roof by as much as 100 degrees Fahrenheit (56 degrees Celsius) [source: Energy Star].

Pick your roofing material and color based on your location. Light-colored roofs tend to reflect heat and are good in warmer climates, while dark-colored roofs absorb heat and are better in cooler climates. If you live in a warmer area or have trouble keeping your home cool, but you don't want to splurge for a whole new roof, you can cover your existing roof with a light-colored coating to lower your cooling costs. Roof coatings can reduce the surface temperature on a roof by 50 to 80 degrees Fahrenheit (28 to 44 degrees Celsius) [source: Washington State University].


When choosing a roofing material, you have many options, including asphalt, metal, wood, concrete and tile. Clay tile and concrete roofs can cost more to install, but they can save you money in the long run because they tend to be more energy efficient than other materials -- in all climates. Avoid unpainted metal and aluminum roofs, which aren't particularly good at releasing energy. One type of roofing material actually makes its own energy. New photovoltaic (PV) cells both protect your home and produce electricity from sunlight.

Saving money on roofing doesn't end with picking the right materials -- you also need to find the right person to install them. Choose a contractor who has a lot of experience installing energy-efficient roofs. You'll also want to find an installer who is licensed and who offers a warranty that covers both the work and the roofing materials.


Lots More Information

Related HowStuffWorks Articles

  • D'Annunzio, John A. "ENERGY STAR and Roofing." May 10, 2004.http://www.edcmag.com/CDA/Articles/Cool_Roof/4289bb13fb697010VgnVCM100000f932a8c0____
  • Energy Star. Reflective Roof Products. http://www.energystar.gov/index.cfm?c=roof_prods.pr_roof_products
  • Federal Energy Management Program. "How to Buy Energy-Efficient 'Cool' Roof Products." http://www1.eere.energy.gov/femp/procurement/eep_roof_products.html
  • Green roofs for healthy cities. About Green Roofs. http://www.greenroofs.org/index.php?option=com_content&task=view&id=26&Itemid=40
  • U.S. Department of Energy. Roofs. http://www1eere.energy.gov/buildings/residential/roofs.html
  • Washington State University. "Reflective Roof Coatings."www.energy.wsu.edu/documents/building/res/roof_coat.pdf