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How to Read Energy Efficient Window Labels

5 minute read


Older windows can let in drafts, leading to a significant increase in energy usage and higher utility bills throughout the year. Replacing these windows with energy efficient ones helps reduce energy bills, lowers your home’s carbon footprint and makes your home more comfortable during Salt Lake City’s cold winters and hot summers. In fact, energy efficient windows can lower your home’s energy bills by up to 15 percent, according to the Environmental Protection Agency (EPA). When you’re choosing replacement windows in Salt Lake City, it’s important to understand how to read energy efficient window labels, so you can select the best type for your home.

NFRC Label

The National Fenestration Rating Council (NFRC) conducts independent testing on windows and other glass products for residential buildings. Windows that are certified by the NFRC have a label on them, but this certification doesn’t necessarily indicate that they’re energy efficient. The NFRC label gives you information on the window’s energy performance, manufacturer, materials, model and style. Understanding this information can help you determine if the windows are efficient enough for the Salt Lake City area. When you look at an NFRC label, you’ll see the following ratings:

    • U-factor: This measures how effective windows are at stopping heat from escaping building interiors. U-factor ratings are usually between 0.20 and 1.20. Lower ratings indicate better efficiency at trapping heat inside, which helps keep homes warmer in winter. In the Salt Lake City area, this means looking for windows with U-factor ratings that are between 0.30 and 0.32.

Interpreting the NFRC label

  • Solar Heat Gain Coefficient (SHGC): This measures how effective windows are at blocking the sun’s heat from building interiors. These ratings are usually between 0 and 1. Lower SHGC ratings mean that windows are able to block more of the sun’s heat, which helps keep homes cooler in summer. However, keep in mind that lower SHGC ratings also mean your Salt Lake City home won’t get as much heat from the sun during the area’s cold winters. Look for windows with an SHGC rating between 0.35 and 0.40 for the best efficiency.
  • Visible Transmittance (VT): This measures the amount of light that comes through windows. These ratings are usually between 0 and 1. Higher VT ratings indicate more natural lighting during the day.
  • Air Leakage (AL): This measures the amount of outdoor air that enters building interiors through windows. These ratings are usually between 0.1 and 0.3. Lower AL ratings mean that windows are able to keep more air out. Keep in mind that this isn’t a required rating, so it won’t be on all NFRC-certified windows.
  • Condensation Resistance: This measures how effective windows are at resisting condensation, or a buildup of water. These ratings are usually between 0 and 100, with higher ratings indicating better resistance to condensation.

Energy Star Label

The EPA’s Energy Star program makes it easy for homeowners to determine how energy efficient certain products are in order to help them save money and protect the environment. All products that meet Energy Star criteria are required to have a label on them. Energy Star labels indicate that windows have met government requirements for energy efficiency. These products are in compliance with the Energy Star program’s standards if they meet the following requirements:

  • Manufactured by an Energy Star partner
  • Tested independently and certified by the NFRC
  • Received NFRC ratings that are in compliance with the Department of Energy’s guidelines on energy efficiency

ENERGY STAR® Climate zones for Windows, Doors, and Skylights

What You Need to Get the Tax Credit

Homeowners in the Salt Lake City area might be able to save money on energy efficient window installation by taking advantage of available tax credits and rebates. These provide homeowners with a way to recover some of the money spent on having these windows installed. In order to qualify for a tax credit, the windows you choose must have two NFRC ratings that are equal to or less than 0.3. If you’re not sure how to get a tax credit or rebate, Advanced Window Products can assist you with this, so you don’t miss out on cost savings.

Window Installation

Choosing energy efficient windows isn’t enough to ensure energy conservation if they end up being improperly installed. Poor installation can result in drafts and air leaks that lead to more energy usage. In order to make sure that your home will be conserving energy, it’s important to hire a reliable contractor to install and fully seal windows at the building envelope.

Contact Advanced Window Products for dependable window installation in the Salt Lake City area. We properly install windows, safely remove old windows, thoroughly clean up after installation and offer limited lifetime warranties. We’ll help you find the most efficient windows for your home and install them the right way, so you can enjoy a more comfortable home and higher cost savings.

Consumer guide to buying energy efficient windows Click the image to download our energy efficient window buying guide.

 

Reviews

Sandra Sk AvatarSandra Sk
I couldn't ask for a better group of hardworking men who did a professional job! Mario, Francisco, and Martin are amazing guys who did a fabulous job! I didn't even know they were here! They cleaned up any and all messes while they were working and when they were done with the job! Communication with the crew was absolutely great! I would reccommend Advanced Windows to anyone, they won't disappoint! I promise you this my friend's! - 2/19/2026 
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John Taylor AvatarJohn Taylor
Advanced Window just replaced three of my windows that were aging and leaking. Eli was the installer and he was excellent. He was extremely knowledgeable and demonstrated an attention to detail and professionalism The new windows matched perfectly and they work just as designed. In addition, Eli cleaned up the work area and left it pristine. The windows were also cost effective. I highly recommend them if you need replacement windows. - 2/10/2026 
Jeremy Knoll AvatarJeremy Knoll
Angel and team did a great job installing my new windows and patio door and wow the difference in noise and heat coming in is amazing. - 2/07/2026 
Kathryn Robinson AvatarKathryn Robinson
We are very happy with our windows. We had an unfortunate rough start but the company moved quickly to solve the problem and our experience from then on was very positive. All Communication with the company was helpful and friendly. Our satisfaction was always their goal. The installers were friendly, careful, respectful and very competent. They completed the installation much faster than we expected and they left everything in perfect condition. We would definitely recommend Advanced Windows to everyone. - 2/06/2026 
McKay Roberts AvatarMcKay Roberts
Got canvased and next thing I know I was buying all new windows and sliding glass doors. We had them do a custom color to paint match some blue trim and it turned out perfectly. The sliding glass doors are also pretty slick with a cool locking feature to make sure they get shut all the way. The only hiccup was one of the windows didn’t fit upon install but they expedited getting another one made which I was really pleased with. Overall I was extremely happy with my purchase and would recommend to others. - 2/05/2026 
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Doug Woodley AvatarDoug Woodley
Advanced windows replaced 4 windows in our house. The whole window replacement took about 4 hours. The installers were very efficient and professional. I would certainly recommend Advanced Windows, and would use them again. - 2/04/2026 
Vicki Henderson AvatarVicki Henderson
We love our new windows! The process from start to finish was smooth. The crew arrived on time and finished installing 15 new windows in one day! I was very impressed. You can’t beat the lifetime warranty and the quality of the windows and installation is top notch. We were well overdue for new windows and the result is fantastic! - 2/03/2026 
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