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Condensation buildup on a window caused by a failed window seal, showing moisture trapped between panes, by Advanced Window Products.

What Causes Window Seals to Fail?

4 minute read


If one or more of your windows show fog or condensation between the panes, you have a failing window seal that needs window seal repair or replacement. Failing window seals can increase your energy costs. They can also cause health problems.

The Critical Role of Your Window Seals

Window seals help maintain a home’s energy efficiency. They also provide protection from outside weather conditions while adding comfort for your family inside.

Deconstructing the Insulated Glass Unit (IGU): What Exactly Fails?

An insulated glass unit (IGU), also known as double-pane glass, is composed of two panes of glass separated by a spacer and filled with either air or an inert gas such as argon and sealed with a synthetic polymer. This creates a thermal barrier, keeping harsh elements out and comfortable temperatures inside the home.

The Primary Culprits: Detailed Causes of Window Seal Failure

There are a variety of factors that can cause window seal failure, by themselves or in combination with others. These factors include improper installation, age, and more.

Temperature Extremes & Thermal Stress: The Cycle of Expansion and Contraction

One of the main reasons for installing IGUs is to help prevent the outside climate from influencing your inside temperatures. In Salt Lake City and neighboring areas, IGUs are essential for keeping frosty winter weather out. Extreme weather fluctuations cause the window’s framing to expand and contract, which puts stress on the seal, potentially causing it to fail.

Environmental Exposure: The Damaging Duo of UV and Weather

Keeping the cold of winter and summer heat out of the house can be hard on IGU seals. Additionally, UV rays emitted from the sun can cause synthetic polymers to break down, causing brittleness and a loss of adhesion.

Material Degradation and Natural Window Age

Age itself, and other factors including sunlight, moisture, extreme temperatures, and weather conditions such as hail, will eventually compromise IGU windows.

Installation Errors and Manufacturing Defects

Not every window installer has the experience and the expertise to get it right. If an IGU wasn’t installed properly or the seal wasn’t correct when manufactured, the seal may fail prematurely, and, in some cases, early in its intended lifespan.

Physical Impact and Pressure Differentials

While a falling limb may hit a window without breaking the glass, there is a chance the seal may be broken by the impact. Additionally, high outside winds can cause enough pressure differential from the calm inside air to break the seal on IGU windows.

 

Benefits and Tips to Seal and Insulate Your Windows for Winter

Recognizing the Red Flags: Signs of a Failed Window Seal

Condensation in the space of windowpanes and fog are the most common and easiest identifiable signs of a failed window seal, but there are others. Those red flags include:

Fogging and Condensation Between Panes

Whether your window becomes completely fogged or you only see a few moisture droplets, either is a sign of a failed window seal.

Distorted Views and Internal Dirt

In some cases, the insulation between the panes will leak out, causing a pressure change between the panes. The result is a wavy or distorted view through the window.

Visible Damage to the Sealant

With age or damage to the frame, you may see visible cracks or peeling, indicating deterioration of the window, necessitating window seal repair or replacement.

Decreased Energy Efficiency and Noticeable Drafts

If you feel a draft near an IGU window, it is likely due to a failure in the seal. Additionally, your HVAC unit may need to work harder, increasing electricity consumption and cost.

The Impact of Failed Seals: Why It Matters

Higher energy bills aren’t the only issue with failed seals. Those broken window seals may start growing mold and mildew due to trapped moisture, which will not only damage the window but can also be a health risk to your family.

Prevention and Mitigation: Extending the Life of Your Window Seals with Advanced Windows

Routine cleaning and inspection of your IGU windows will help keep them in order. Calling Advanced Windows for a complete inspection will help prevent unexpected issues from happening and extend the life of your windows.

Protecting Your Investment in Home Comfort and Efficiency

As Utah’s top window installation and repair company, Advanced Windows can help reduce the number of necessary window replacements through inspection and window seal repair services. Call us today.

 

Image credit: // Shutterstock // Paul Maguire

Reviews

Heather Nava AvatarHeather Nava
We recently had new windows installed and the difference has honestly been incredible. The first thing we noticed was the noise reduction. We live close to two major roads, and traffic noise used to wake me up constantly throughout the night. Since installing these windows, it’s amazingly quiet inside the house — I can barely hear anything outside now. That alone has been life-changing for us.Beyond the sound reduction, the windows completely upgraded the look of our home. They feel modern, high-quality, and extremely well made. The value for the price was excellent, especially considering how much they improved both comfort and appearance.We’ve also noticed a huge difference in temperature control throughout the house. Rooms stay much more comfortable, and the home feels far more energy efficient overall. The house maintains temperature better and feels less drafty no matter the time of day.Overall, we could not be happier with the investment. The combination of appearance, quality, energy efficiency, and especially the noise reduction exceeded our expectations. - 5/12/2026 
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ray bush Avatarray bush
If you are on the fence about using Advanced Windows, go ahead and take the leap. The entire experience was seamless and professional. Mason was our initial sales contact. He was never pushy but he simply gave us the facts and let us ask the questions and do the research. He gave us a list of nearby addresses of customers. We drove by each one and even rang doorbells. Yes we sure did! All were happy with their choice and the windows are beautiful. They use argon gas in between panes and you really notice how the transfer of heat is stopped in the Arizona sun. Truly a game changer. The windows are manufactured by the same company used by the higher end companies but at a much more affordable cost. Life time warranty to boot.The installation team was outstanding. I asked for their names because they deserve a shout out Francisco,Mario,Julio,Saul and Martin. If you can, ask for them by name. They were professional, knowledgeable,detail oriented,courteous and clean. No mess. The company got our windows done in 1 day which is mostly due to this team’s hard work and due diligence. I will recommend this company to anyone! The windows work effortlessly and really add to the appearance of our home. I have no doubt the was one of the best decisions we have made to add value to our home. - 5/11/2026 
Susie Steenblik AvatarSusie Steenblik
My windows are beautiful that I got from Advanced Windows. Dallin helped me order my windows and he was amazing to work with. So professional and helpful. Gasson and his crew are second to none. You definitely want them when it comes to installation. They are perfectionists and will make sure everything is the exact way you want your windows to be. Grace in the office is kind and on top of scheduling all of the appointments. I would definitely recommend Advanced Windows if you are thinking about getting new windows. - 5/11/2026 
Dave Thomas AvatarDave Thomas
This is the second year in a row they washed my windows. The glass turns out looking brand new! Their customer service is outstanding. I wouldn’t use anyone else. - 5/11/2026 
Chris Gloschat AvatarChris Gloschat
From the first meeting where we discussed the product and price to the installation the whole Advanced Windows team was excellent. The price was great, the product is great, and the fact that they manufacture locally means I'm not worried about them being able to make good on any warranty issues. I recommend them wholeheartedly and would use them again. - 5/08/2026 
Paul Felice AvatarPaul Felice
Everyone we contacted were professional, helpful and clear - 4/16/2026 
Braulio Pisano AvatarBraulio Pisano
It was great working with Advanced Window Products. The 0% finance and over all cost of our 15 windows was the lowest price out of 4 other companies.Installation was fast and easy only taking 2 days. We had a few issues and the team came back is fixed them in less than 1 hour. All our windows work great and we can feel the difference already.Looking forward to see how well the windows perform in summer - 4/16/2026 
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