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Air Leakage: How It Affects a Window’s Energy Efficiency

Remember, a one-size-fits-all approach won’t work in choosing a new energy-efficient window. Everyone knows you should look for an ENERGY STAR® certification, but how do you pick one from dozens of windows that have that label? You look at its U-factor, solar heat gain coefficient (SHGC) and air leakage rating (AL) ratings.  

What the AL Rating Means 

The AL indicates the amount of air that can pass through a square foot of a window. A window with an AL of 0.1 lets in the least amount of air while a window rated 0.3 lets in the most amount of air. However, this doesn’t mean you should avoid windows with a rating that’s more than 0.1 – as long as the AL is below 0.3, the window can be considered energy-efficient. 

Here’s a tip: if you’re looking for a window with a low AL, try looking for double-pane replacement windows

How Does It Affect Your Home’s Energy Efficiency?

Of course, drafty windows, ones with a rating of more than 0.3, can raise your power costs; heat and air-conditioned air can leak out of your home, forcing your HVAC unit to consume more power to maintain a comfortable temperature inside. 

How to Pick the Right Window 

However, keep in mind that although a window’s AL is an important aspect, it isn’t the only one. When evaluating window performance, you need to factor in its several other features. One feature can’t make a window entirely energy-efficient. Our energy-efficient windows have a variety of features like Fibrex® frames with excellent insulation capabilities and ultraviolet-blocking High Performance™ Low-E4 glass. 

One more thing: make sure only a qualified company installs your new energy-efficient windows. Installation errors can leave behind gaps, which can then let in drafts. 

Renewal By Andersen® of St. Louis, an independently owned retailer with an A+ rating from the Better Business Bureau, offers a wide variety of premium windows and doors. To schedule a free consultation with one of our design specialists, call us at (314) 983-9977, or fill out our contact form here. We serve homeowners in Chesterfield, MO, as well as other nearby areas.

Reviews

"This was one of the best experiences I've ever had with a company. I ordered the windows in November and was told they wouldn't be here until July. That kind of delay the new norm so I wasn't a bit upset with the timeline. I was given an early present when they called to say the windows would be in at the beginning of May. We agreed on the week of May 16th to do the installation, there were 30 windows and a sliding door to install. They arrived promptly on their scheduled install date, and got straight to work. By the end of day one, they had all the upstairs windows complete and their work was incredible. Day two came with more of the same, the crew showed up promptly, got straight to work, and when they left they had every window downstairs installed. The third day they again arrived on-time, and got to work installing the door. The door and windows are perfectly installed. The two lads that did the installation did a phenomenal job, and were friendly to boot. I would give them more business if I had any :) The service I received from the company was great. They kept me abreast of anything that was going on with my order. I appreciate my concierge, Christina, she was good at communicating timelines and getting everything scheduled."

Lane Maxwell
Jun 28, 2022

"The two installers were great! They were polite and hard working and they cleaned up all the outside and inside. It was like they were never here. As for the windows, I love them, not only looks great, they are efficient. Now every window in my home has Renewal by Anderson."

Mark Palsgrove
Jun 23, 2022

"We had the pleasure recently of having Andersen replace all of our windows. From the very first interaction with the office personnel through the completion of the project, they have been nothing but professional. From Brian our sales rep to Christina the appointment scheduler, they were a pleasure to interact with. Installers Keith, John, and Evan were fantastic to work with. They went above and beyond to repair an area which was slightly damaged during the removal of a window...caulked and painted it. They took extra precaution to ensure the floors were covered while working inside and cleaned up each day inside and out. We love the look of our new windows and can't wait to enjoy the savings in utilities they'll provide. Thanks so much Renewal by Andersen!!"

Kevin Corrigan
Jun 15, 2022

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