EZ

U-Value

Represents the heat flow rate through a window expressed in thermal units, using winter weather conditions of -17°C outside and 21°C inside. The smaller the number, the better the window system is at reducing heat loss.

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R-Value

The higher the R-Value, the more efficient the window is in reducing winter heating costs. (This number is the inverse of U-Value.)

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Solar Heat Gain Coefficient - (SHGC)

The amount of solar radiation that enters a building as heat. The lower the number, the better the glazing is at preventing solar heat gain.

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Shading Coefficient 

Measures the total amount of heat passing through the glazing (total solar heat transmittance) compared with a single clear glass. The lower a window’s solar heat gain coefficient or shading coefficient, the less solar heat it transmits, and the greater its shading ability.

 

Fading Transmission 

The portion of energy transmitted in a spectral region from 300 to 700 nanometers. This region includes all of the ultraviolet energy and most of the visible spectrum and will give the best representation of relative fading rates. The lower the number, the better the glass is for reducing the fading potential of carpets and interior furnishings.