Energy Efficiency Home Improvement Replacement Doors Replacement Windows

ENERGY STAR® Labels 101: What They Mean and How to Read Them

3 min read

If you have shopped for appliances, windows, or doors recently, you’ve almost certainly seen ENERGY STAR® labels. They may look complicated, but they’re there to help you make smarter, more energy-efficient choices.

At Window World, we’re proud that our replacement windows and doors have all earned the ENERGY STAR label. We’re dedicated to making sure your replacement products are as energy-efficient as they are beautiful.

With that in mind, let’s explore ENERGY STAR labels so you know what to look for next time you’re shopping for new windows or doors.

What Does the ENERGY STAR Label Signify?

The ENERGY STAR label is placed on products like windows, doors, and appliances to signify that it is more energy-efficient than traditional products. This saves energy, decreasing your carbon footprint and saving you money on your energy bills each month.

energy star logo

ENERGY STAR Label Requirements

To qualify for the ENERGY STAR label, products must meet strict standards and pass rigorous testing. The process is overseen by the Environmental Protection Agency (EPA), while testing is performed by the National Fenestration Rating Council (NFRC). Current EPA standards for the ENERGY STAR label are:

How to Read ENERGY STAR Labels for Windows and Doors

ENERGY STAR labels are designed to make it easy for consumers to spot energy-efficient products. By simply spotting the blue ENERGY STAR logo, you know you’re investing in an energy-efficient product.

The NFRC label gives you in-depth information about the product, allowing you to compare two or more energy-efficient products. 

Reading an ENERGY STAR Window Label

If you’re shopping for replacement windows, you might see these labels on windows. Here’s how to read the information on them.

U-Factor measures how well a material is at keeping heated or cooled air from escaping a room. U-Factor runs on a scale of 0.20–1.20. The lower the number, the more efficient it is. 

Solar Heat Gain Coefficient (SHGC) measures how well a product can resist unwanted heat gain and solar heat absorption. SHGC range is 0-1, with lower numbers being more efficient.

Visible Transmittance measures how well a window lets light into your home. It is measured on a scale from 0-1. Higher numbers let more natural light in.
Air Leakage measures how much air seeps in through a product. In other words, how drafty the window is. Air leakage is less than 0.3, with lower numbers being more efficient.

Reading an ENERGY STAR Door Label

Glass space is one of the biggest factors in a product’s energy efficiency. Since doors can contain varying amounts of glass depending on the door style, they don’t have the same type of label as a window. 

Here’s what you’ll see on an NFRC door label:

Product description is a short description of the door and its material.

U-Factor functions the same on a door as a window: it measures how well the door will keep heated or cooled air from escaping. Like with your windows, you’ll want to look for lower numbers.

Solar Heat Gain Coefficient (SHGC) measures how well your door will resist heat gain and solar heat absorption. Look for lower numbers to avoid having your door absorb heat and radiate it into your home.

Improve Your Home’s Energy Efficiency With Window World of Colorado

Whether you’re in the market for replacement windows or doors we have the perfect solution for you! Explore our product lines and schedule your free consultation to learn how we can help improve your home’s energy performance and lower your monthly bills.