ENERGY EFFICIENCY
The Learning Center
U-value (or U-factor) is the measure of the window's ability to conduct heat—in other words, the amount of heat transmitted through the
window. The lower a window's U-value, the better the window is at insulating your home. Generally, heat will flow from the inside towards
the outside during the winter. In the summer, it will flow from the outside to the inside. Most manufacturers have run NFRC (National
Fenestration Rating Council) thermal performance tests on assembled units, which are a much better indicator of the unit’s overall
performance, compared to glass or window frame values alone.
5. What is a U-value?
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1-877-SWING CLEAN
info@energyswingwindows.com
3245 Miracle Drive
Murrysville, PA 15668
724-387-2991
PA Contractor ID
PA001856