Replacement Windows and Energy Performance Ratings

When you are planning to install new replacement windows for your home, it’s important to take into account the energy performance ratings of your new hardware. Thankfully, the NFRC has made this easy for homeowners like you by creating a handy label to refer to.

In this post, our experts at Renewal by Andersen® of Eastern New York discuss what each NFRC measurement tells you about your new windows.

The U-Factor

The orange-colored box in the label measures how well the window keeps heat from escaping from the inside of a room. As a general rule, the lower the U-Factor, the better a product is at keeping heat in. The average range for U-factor falls between 0.20 and 1.20. Our window company recommends looking for low numbers as you want your window frames to retain as much heat from within your home as possible.

Solar Heat Gain Coefficient

The numbers in the purple box tells you how well the window can resist unwanted heat gain, which is a vital trait all modern windows have. This is especially important during summer when the heat can speed up the decay and disrepair of the window frames.

The average range for Solar Heat Gain Coefficient is between 0-1. Just like the U-factor, always look for low numbers. It’s rare to see a window with a completely zero solar heat gain coefficient. What you’ll most likely see are decimals, so always pick the lower ones.

Visible Transmittance

The numbers in the green box tell you how well the window effectively lights your home. This is an important money-saving measurement and for daylighting, and you’ll want higher numbers for this. The range is between 0-1, so choose the highest possible between this range.

Air Leakage

The numbers in the dark blue box measure how much air “naturally” enters through the window and into the room when closed. This is outside of air leaks, and the range is between 0.1 to 0.3. As with the previous measurements, you’ll want to look at low numbers so that you get a weathertight window.

As your local window contractor, Renewal by Andersen® of Eastern New York installs energy-efficient windows made with our proprietary Fibrex® composite window frame material. Give us a call at (866) 479-1700 for more information on our products and services.