Windows are a critical component in sustainable building design. Most energy flows in and out of a building through its windows, but with intelligent design and technological innovation they can be used to provide heating, cooling and lighting for a better indoor environment.
Here is what to look for:
Click here to see a list of our green window manufacturers:
Wood (includes Vinyl and Aluminum Clad)
Fiberglass
Vinyl
Aluminum and Commerical
Creates an insulated air space between the two pieces of glass, resulting in better thermal performance. Insulated glass also reduces condensation while keeping the heat in during the winter, and heat out during the summer.
Low-E Glass: Low-E Glass is coated with a virtually invisible layer of silver that reflects radiant solar energy while permitting visible light to pass through the glass. Low-E Glass can either have a low Solar Heat Gain Coefficient (the best choice in climates dominated by cooling) or a high SHGC ( the best choice in climates dominated by heating or for south facing windows in climates with a mix of cooling and heating requirements).
Argon Gas: Added inside an insulated panel with Low-E Glass, Argon gas is an invisible, insulating blanket that replaces most of the air during the manufacturing process. With Low-E reflecting heat away, Argon gas buffers thermal transfer to enhance the performance of the whole glass panel.
Certifications and Ratings
National Fenestration Ratings Council (NFRC): Look for the National Fenestration Ratings Council (NFRC) label on the window or patio door. This label shows the U-Value, Solar Heat Gain, and visible light transmittance values.
Energy Star® Rated: Energy Star® is a national campaign sponsored by the EPA and the Department of Energy to promote energy efficient products.
R- and U-Values: R-Value is a term that measures the insulation properties of a material like insulation, but the energy efficiency of windows is measured by ‘U-Values’. The higher the R-Value, the greater its insulating ability, but for U-Value, the lower the number the better that product’s insulating efficiency. To find a U-Value, divide the number ‘1’ by the R-Value. For example, an R-Value of ‘4’ is equal to a U-Value of .25.
Here is what to look for:
Framing
Wood frames are very energy efficient, and are available in FSC wood, but can also be expensive and need to be sealed or painted regularly to protect them from water damage. Fiberglass frames are low maintenance and energy-efficient but can also be expensive. Aluminum frames are inexpensive but conduct heat easily and are therefore less energy efficient than other options.Click here to see a list of our green window manufacturers:
Wood (includes Vinyl and Aluminum Clad)
Fiberglass
Vinyl
Aluminum and Commerical
Glass Options
Insulated GlassCreates an insulated air space between the two pieces of glass, resulting in better thermal performance. Insulated glass also reduces condensation while keeping the heat in during the winter, and heat out during the summer.
Low-E Glass: Low-E Glass is coated with a virtually invisible layer of silver that reflects radiant solar energy while permitting visible light to pass through the glass. Low-E Glass can either have a low Solar Heat Gain Coefficient (the best choice in climates dominated by cooling) or a high SHGC ( the best choice in climates dominated by heating or for south facing windows in climates with a mix of cooling and heating requirements).
Argon Gas: Added inside an insulated panel with Low-E Glass, Argon gas is an invisible, insulating blanket that replaces most of the air during the manufacturing process. With Low-E reflecting heat away, Argon gas buffers thermal transfer to enhance the performance of the whole glass panel.
Certifications and Ratings
National Fenestration Ratings Council (NFRC): Look for the National Fenestration Ratings Council (NFRC) label on the window or patio door. This label shows the U-Value, Solar Heat Gain, and visible light transmittance values. Energy Star® Rated: Energy Star® is a national campaign sponsored by the EPA and the Department of Energy to promote energy efficient products.
R- and U-Values: R-Value is a term that measures the insulation properties of a material like insulation, but the energy efficiency of windows is measured by ‘U-Values’. The higher the R-Value, the greater its insulating ability, but for U-Value, the lower the number the better that product’s insulating efficiency. To find a U-Value, divide the number ‘1’ by the R-Value. For example, an R-Value of ‘4’ is equal to a U-Value of .25.