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Replacement Window Ratings

Replacement Window Ratings and the NFRC Label

What is a NFRC rating label?

The U.S. Department of Energy created a program called the National Fenestration Rating Council or “NFRC” which is designed to assist consumers when comparing different replacement windows and products. Window manufactures that participate in the program are required to place a label on each window that lists its thermal performance level. Not every window manufacture participates in the NFRC program but many of the larger more reputable replacement window manufactures do. The label is designed to interpret important energy related factors for window products.

How read the NFRC label

NFRC Label Replacement Windows

The label will include the companies name the window series or model number, the type of window, i.e. casement, double hung, etc… the type of material the frame is constructed out of i.e. vinyl clad, wood, etc… There are four main performance ratings:

U-factor rating: This rating is important for the winter heating seasons. U-factor ratings are usually between .020 and 1.20. The lower the number the better the window product will keep heat in a structure.

Solar Heat Gain Coefficient (SHGC) rating: This rating is important during the summer and cooling seasons. This rating represents how well the replacement window product will block unwanted from penetrating the window. The number is normally a 0 or a 1 the lower the number is a better.

Visible Transmittance (VT) rating: This VT rating measures the ability that the window product can transmit sunlight. The VT number rating are usually a 0 and 1 the higher the number the more light the window product will allow through.

Air Leakage (AL): The AL rating measures the how well a window product will keep air out. The number is normally in a range between 0.1 and 0.3. The lower the number the better this window product prevents air leakage or keeps air out.

If you have specific questions about new windows, doors, and skylights for you home ask the home improvement professionals at Metropolitan Design/Build. We can help you make the right energy efficient window choices. That’s what we do!

Contact the local area window experts at Metropolitan Design/Build by calling 866-20-3565 or completing our online form on this page. We provide free estimates on replacement windows, doors, and skylights, start reducing energy costs today!


Contact Metropolitan Design/Build today by calling (301) 870-2145 or by completing our online form on this page providing us with the details of your project.

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