Energy Star Windows

{{Infobox
|title = Energy Star Windows
|image        = [[File:Space holder.jpg|215px|alt=Block Glass Windows]]
|header5 = Other Names:
|data6 =  Energy Star Windows Program for Replacement Windows
|header7 = Description:
|data8   =  Certification program used to evaluate the energy efficiency of replacement windows.}}

The '''Energy Star''' certification provides information about a window's ability to limit heat transfer, resist weather and control the amount of solar gain that penetrates into a home through the windows. Energy Star qualified windows lower household energy bills between 7-15 percent by providing an energy efficient window. Many governments encourage use of Energy Star windows because they lower energy consumption and reduce greenhouse gas emissions.

== Background ==
Energy Star is a joint program of the United States Department of Energy and the United States Environmental Protection Agency. The program's objectives involve assisting homeowners to save money and protect the environment through responsible environmental practices which include the purchase and installation of energy efficient products.

It is estimated that using energy efficient products can save homeowners approximately one third of their energy costs. Simultaneously the community reduces greenhouse gas emissions. Energy Star qualified [[Replacement-Windows|replacement windows]] are stylish and comfortable but the addition of thermal insulation and the reduction of solar gain presents added elements which provide long-term benefits that non-energy efficient windows do not. 

== Benefits of Energy Star Windows ==
Energy Star windows save money, offer comfort and protect the home's furnishings. 

=== Save Money ===
Installing Energy Star qualified windows saves money by lowering energy bills. Using energy efficient windows means that less energy is required to heat or cool a home. Estimates indicate that installing Energy Star replacement windows saves between 7 to 15 percent of energy expenses compared to non-qualified products. The savings mean that homeowners can recoup the increased cost of an Energy Star window within four to seven years of purchase due to energy cost savings.

These estimated savings vary, depending on heating and cooling costs in a specific region.

=== Comfort ===
Energy Star qualified windows help to keep a home’s temperature consist and comfortable. Windows which offer thermal insulation and reduction of heat gain, help a home to maintain a comfortable temperature without a corresponding increase in energy consumption. 

=== Protect Furnishings ===
Many Energy Star qualified replacement windows feature special glass coatings which block the sun's rays and protect drapes, furniture, wood floors and other furnishings. The coating blocks exposure to direct sunlight to limit exposure to the sun. It is estimated that these coatings reduce fading by up to 75 percent.

== Energy Star Window Performance ==
Energy Star reviews a window's U-Factor and the Solar Heat Gain Coefficient.

=== U-Factor ===
The U-Factor determines the rate at which heat passes through the window -- the window's conduction. This rating represents the insulating performance of the entire window including the window's glazing, frame and spacer material. A low U-Factor provides the most energy-efficient window. 

=== Solar Heat Gain Coefficient ===
Solar Heat Gain Coefficient refers to the percentage of solar radiation which is either absorbed or directly transmitted through a window. When a reduced amount of solar heat is transmitted there is a lower solar heat gain coefficient (SHGC). Windows with high SHGF ratings transmit increased solar heat gain during the winter months while windows with a low SHGF ratings reduce cooling loads most effectively during the summer months as they block the sun's heat.  The desired SHGF will depend on the home's location. 

== Energy Star Label Acquisition ==
A window manufacturer may apply for an Energy Star label if the window meets the requirements for an energy efficient window as set forth in the product specifications. The National Fenestration Ratings Council, a non-governmental body affiliated with the United States Environmental Protection Agency, tests the windows to measure their energy performance. One of the central measurements of the program includes verification that purchasers will be able to recoup the additional cost of an energy efficient window through energy savings within a reasonable period of time.

[[Category:Replacement Windows]]