ENERGY STAR^® labeled roof products can help you save money and the environment by reducing your energy use. They work by reflecting more of the sun's energy back into the atmosphere, keeping your building cooler and reducing your air conditioning bills. Because much of the United State's electricity is generated by burning fossil fuels, creating air pollution, reducing the amount of energy needed to cool buildings helps to reduce the production of air pollutants.

In addition, the air in urban areas can be 6-8°F hotter than surrounding rural areas. Scientists call these areas "urban heat islands." These heat islands can make the effects of local air pollution, like smog worse, and can increase the cooling costs for buildings within the area affected by the heat island. Click here for more information on urban heat islands.

This calculator helps you estimate how much energy and money you can save by installing an ENERGY STAR^® labeled roof product on your home or building. Please take note of the following when using the roofing calculator.

• The building should be an air-conditioned residence (assumed to have a roof with 20% slope), office, or retail/commercial building. No savings are available for a building that is not air conditioned, although a reflective roof can make it cooler.
• The calculator asks you to supply the equivalent flat roof area. If you are calculating the savings for a building with a sloped roof you should specify the area of the floor space covered by the roof. For multi-story building give the square footage under the roof (usually the top story).
• This calculator calculates net savings for buildings, balancing cooling savings with minor increases in heating costs. The calculator works for buildings heated by gas or an electric heat pump.
• To correctly calculate cooling savings and heating costs, this calculator takes into account the amount of insulation in your roof. Savings from cool roofs are largest for lightly insulated roofs. Buildings with highly insulated roofs save energy during the heating season and the cooling season because the insulation slows the flow of heat into and out of your building. See map for insulation levels recommended by the DOE.

The roofing calculator is intended to roughly estimate the savings a reflective roof can offer to a typical building and aid in the decision whether to choose a reflective roof. If you are interested in estimating savings for a particular building or calculating cost-benefit ratios for a project you should consider using a detailed building energy simulation.

The roofing calculator estimates annual energy savings for typical building types with non-metallic-surfaced roofs using typical weather conditions. These estimates were derived based on simulations run with the DOE-2.1E model using cooling and heating degree-days. Actual savings will differ based on building design, building operation, cooling and heating equipment, and local weather.

The roofing calculator does not include savings from monthly peak demand reduction charges, reflective roof rebate programs, or load-curtailment programs. The roofing calculator does not include the effect of snow on a roof. Snow on a roof may reduce the heating penalty associated with a reflective roof by providing some additional insulation depending on the depth of the snow.