Energy Efficiency
Improve your Home’s Performance with Energy Efficient Windows and Patio Doors
Replacement windows and patio doors have many benefits for homeowners – the reduction of energy use associated with heating and cooling the home is only one of these benefits. Windows are certified by the National Fenestration Rating Council, which takes the guesswork out of comparing windows by providing industry standards for the most common measures of window performance.
Solar Heat Gain Coefficient (SHGC)
U-Factor measures the products effectiveness preventing heat from escaping. The rate of heat loss is indicated in terms of the U-Factor (or U-Value) of a window unit. The lower the U-Value, the greater the windows resistance to heat flow, and the better its insulating value.
Visible Light Transmittance (VLT)
Windows allow light to come inside, but not every window allows the same amount of light through. VLT equates to the amount of light allowed in through a window – the higher the percentage, the more light.
U-Factor
U-Factor measures the products effectiveness preventing heat from escaping. The rate of heat loss is indicated in terms of the U-Factor (or U-Value) of a window unit. The lower the U-Value, the greater the windows resistance to heat flow, and the better its insulating value.
Climate Considerations
When it comes to managing your home’s energy performance, there isn’t a single solution for every climate or even for every room. ENERGY STAR helps guide selections by identifying ideal performance characteristics for all the climate zones in the USA.
Air Leakage (AL)
Air leakage is indicated by a rating expressed as the equivalent cubic feet of air passing through a square foot of window area (cfm/sq ft). Heat loss and gain can occur by infiltration through cracks in the window assembly. The lower the AL, the less air will pass through cracks.
Condensation Resistance
CR measures the products ability to resist the formation of condensation on the interior surface. While this rating cannot predict condensation, it can provide a credible method of comparing the potential of various products for condensation formation. CR is expressed as a number between 0 and 100, with a high rating indicating high performance.
UV Block
Invisible, yet harmful, ultraviolet (UV) rays from the sun can cause paint, furniture stains, carpet, and window treatments to fade. The higher the percent, the more harmful UV rays are blocked.
