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The 6 Metrics of Whole-Window Performance

From installing brand new windows to replacement windows, it is important that you know the quality of what you are getting. Every window has a different feature and you may be looking for certain ones. In that case, assessing a window’s whole performance is necessary.

The 6 Metrics of Whole-Window Performance

However, what are the measurements used when doing one? Renewal by Andersen? lists all six of them.

  • U-Factor

This calculates the rate of heat loss of a window. The lower the U-factor, the better its insulating properties are. Low U-factor is beneficial for people living in hotter places. Therefore, homeowners must learn what U-factor best suits their climate.

  • Solar Heat Gain Coefficient

Expressed as a number between 0 and 1, SHGC is used to measure the solar radiation admitted through a window. The lower the SHGC is, the less solar heat it transmits.

  • Visible Transmittance

Many modern windows have spectrally selective coatings so when it comes to window replacement, measuring the fraction of visible light transmitted through the window is important.

  • Air Leakage

By assessing the amount of air that passes through window cracks, one will know the cause of heat gain or loss. Homeowners should pick windows with an AL of 0.30cfm/sq ft or less to attain better energy efficiency.

  • Condensation Resistance

This metric is used to check how well a window resists condensation on the inside surface. Rated between 1 to 100, the higher the number, the better its resistance to condensation.

  • Sound

A window that is airtight generally filters outside noise. Through measuring sound transmission, one can get an idea of how well a window can prevent air leakage.

Armed with these six metrics, you can now do a whole performance test before choosing windows for your home. For the best windows around, look for the best window replacement contractor, Renewal by Andersen of Atlanta. To learn more about what we can do for you, simply give us a call at (888) 908-3332. We serve homes in Atlanta and the surrounding areas.


"Awesome job! Everything was completed as communicated. Everyone was very courteous and friendly. Other contractors should follow the Renewal by Andersen footprint."

Richard & Camille, Lawrenceville GA January 22
May 25, 2016

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