When choosing replacement windows, the small National Fenestration Rating Council (NFRC) label contains a big message to help you make an informed decision. You should know how to read it properly to determine the most suitable ENERGY STAR®-approved units for your home.
In today’s post, Renewal by Andersen® of St. Louis talks more about the ratings on the NFRC label:
U-Factor
This measures how well energy-efficient windows prevent heat from transferring from the inside of the room to the outside. Expressed in a range between 0.20 and 1.20, the lower the value, the better the unit is at insulating thermal energy.
Solar Heat Gain Coefficient (SHGC)
This measures how much solar radiation the unit allows inside. Expressed in a range of 0 to 1, the lower the value, the better the window is at reflecting the sun’s infrared light.
All windows installation experts agree that every climate zone demands a unique combination of U-factor and SHGC. In St. Charles County, the maximum U-factor and SHGC ratings every window must have are 0.30 and 0.40, respectively.
Visible Transmittance (VT)
This measures how much daylighting the window provides. Expressed in a range between 0 and 1, the higher the VT value, the more sunshine it allows to pass through the glass.
Air Leakage
This measures how well the window prevents air infiltration. Expressed in a range of 0.1 to 0.3, the lower the number, the less drafty it is. By and large, casement windows are the most leak-resistant of all operating units because their sash presses against the frame when closed.
Condensation Resistance
This measures how much moisture the window allows to accumulate on its surface. Expressed in a range between 0 and 100, the lower the value, the less condensation you’ll see. While this rating is generally optional, it’s imperative to keep it in mind when choosing your new windows.
Renewal by Andersen of St. Louis windows have the best combination of ratings to meet and exceed ENERGY STAR’s standards. Call us at (314) 310-3636 to schedule your consultation, learn more our high-performance products and receive a FREE estimate. We serve St. Charles and other Missouri communities.
