How to Read a Window Energy Efficiency Label

Energy Efficient Windows Can Reduce Your Heating and Cooling Bills by 10-25 Percent*

Is it time to finally replace those drafty old windows on your home? With the current emphasis on energy efficient windows, the National Fenestration Rating Council (NFRC) has designed an energy-performance label to guide contractors and homeowners in their search for the perfect window. Since the weather conditions in Minnesota vary widely from season to season, checking the label before ordering the window can make a big difference in how much the window can help keep energy costs to a minimum.

Unsure what all those numbers and codes on the label mean? Once you know what to look for, you’ll be able to find exactly the right windows. Here’s a quick breakdown:


This is one of the most important ratings that the NFRC provides. The U-factor tells you how well a window is at preventing heat from escaping a home or an establishment. U-factor ratings are usually between 0.15 and 0.20. The lower the U-factor rating of a product is, the better it is at preventing heat from escaping.


This stands for solar heat gain coefficient, and it’s also one of the more important ratings in an NFRC label. This measures the amount of heat that a product can block. This rating is usually between 0 and 1. The lower the SHGC rating, the better the product is at blocking solar heat gain.


Visible transmittance, also known as VT, is one of the additional energy efficiency ratings that the NFRC gives. This rating tells you how much light passes through a product. This is also expressed between 0 and 1. Unlike other measurements, the bigger or higher the VT rating of a product is, the more light it allows to pass through.

Air Leakage

Air leakage is another energy efficiency rating. It measures the amount of outside air that is able to seep into the interior through the product.

Condensation Resistance

Condensation resistance measures the ability of a product to resist the formation of condensation on the interior surface of that product. The higher the CR rating, the better that product is at resisting condensation formation. CR is expressed as a number between 0 and 100. This rating is optional and manufacturers can choose not to include it.

NFRC energy efficiency ratings are important to understand to ensure that the product you’ll purchase offers superior performance. For more information on NFRC ratings, visit the organization’s website at

There are so many things to consider when shopping for replacement windows; let The Chuba Company help with their years of exterior remodeling and window replacement expertise. With over 125 years of combined experience in the roofing and exterior construction industry, The Chuba Company provides quality installation and dedication to our clients. Contact The Chuba Company today!

*Source: Consumer Energy Center