U-Factor Performance Ratings

To prevent deceptive energy efficiency claims, the U.S. Environmental Protection Agency (the EPA) and the U.S. Department of Energy require that windows be tested and certified by the National Fenestration rating Council (NFRC). The windows are tested by a government approved agency and given a certified efficiency value, the U factor. The rating is based upon the efficiency of the whole window, not just the center of the glass. The label shows exactly how each window is made, its efficiency rating, and it must be attached to the glass of each window ad it is manufactured.

The NFRC label, which can be found on all ENERGY STAR qualified windows, provides performance ratings in a number of categories:

U-Factor measures the rate of heat transfer and tells you how well the window insulates. The lower the U-Factor, the better the window insulates.

We are very proud that our windows have earned the lowest U-Factors in the country:

  • Our Super High Performance Model 5400 Maxi Triple Pane Double-Hung and Sliders have a U factor of .16
  • Our Super High Performance Model 5400 Maxi Triple Pane Casements have a U factor of .17
  • Our High Performance Model 4200 Maxi Triple Pane Double-Hung and Sliders have a U factor of .20
  • Our High Performance Model 4200 Maxi Triple Pane Casements have a U factor of .21
  • Our High Performance Model 4100 Maxi Double Pane Double-Hung and Sliders have a U factor of .26

We are very proud that our windows not only exceed today’s U factor requirements, but future requirements as well.  Tristate Super High Performance Windows are many years ahead of other windows from  our competitors. Reinforcement with aluminum adds 2 additional points to the U Factor.

U-Factor .16, SHGC .21
U-Factor .17, SHGC .18

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