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Common Signs of Window Seal Failure

Today’s windows usually have sealed glazing as part of their design. Because of this, these windows are more commonly called insulated glass units (IGUs), insulated windows or thermopanes. However, after some years, the seals on these windows could fail due to a variety of reasons. This then reduces the insulating capacity and clarity of the windows.

In this post, sliding doors and windows specialist Renewal by Andersen® of Montana shares a few tips on how to tell if your window seals are broken.


A drafty window is not always something to worry about. But when it turns out to be a cause for concern, it is often due to a broken seal. That said, it is best to hire a professional to conduct a thorough inspection of your windows so that you can identify the real reason behind the drafts. In worst-case scenarios, window replacement is usually the ideal solution.


Condensation is a common result of a broken window seal. It usually occurs when a window has to withstand a constant or increased rate of expansion and contraction. Much like doors, windows are generally designed to expand and contract, as weather and temperature change. But if the fluctuations become more constant, these can put a strain on the seal and create small fractures.

Glass Distortion

Another sign that you should look out for is glass distortion. If your windows are filled with argon or krypton gas, they may bow in the middle when gas leaks out. This is definitely a sign that your seal is no longer able to perform its function.

Renewal by Andersen of Montana is known for high-quality window and door products. We offer a range of window styles as well as sliding and patio doors to suit different tastes of clients. Call us at (406) 259-3944 or fill out our contact form to request a free quote.


"I highly recommend Renewal by Andersen. We were treated well and everything went smoothly from start to finish. The company kept in contact with me before, during, and after the installation and let me know what to expect. I'm in love with my new windows! I will be using this company again when we refinish our basement. "

July, 21

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