There are many things that can go wrong with your window that require repair, but one of the most urgent issues you should fix immediately is a broken window seal. Thankfully, it’s possible to tackle window seal repair yourself if you have the right tools and know-how.

In this guide, I’ll be discussing how to tell if you have a failed seal, some reasons window seals break, and how to fix the problem once you identify it. I’ll also explain if a DIY or professional repair is better and how to prevent window seals from breaking in the future.

*Costs in this article sourced from contractor estimates used by Fixr and Angi.

What Are Window Seals?

Windows seals are the barrier between the window frame and glass panes. They help to prevent dust, water, pollutants, and air from entering the home, and can be key to keeping a room at a comfortable temperature. Window seals also aid with energy efficiency as they prevent heat loss in the winter and keep heat out in the summer.

How to Tell if Your Double-Pane Window Seal Is Broken

Before I dive into how to fix a broken window seal, you need to be able to identify if a broken seal is really the issue. There are a few things you can look for, including:

Condensation Between the Panes

The most obvious sign of a broken window seal is condensation on your window that can’t be wiped off. A foggy window is a clear sign that condensation is forming between the panes of glass on a double-pane window or a triple-pane window. That means the insulative inert gas — usually argon gas or krypton gas — that was vacuum sealed between the panes has escaped, and the void is open to outside air and moisture.

If you have a double-pane window moisture problem, check out our double-pane window moisture removal guide.

A Drop in Your Home’s Energy Efficiency

If you’ve noticed that your heating and cooling costs have increased unexpectedly, it’s a good sign that you have a broken window seal on your hands. A broken seal will not provide proper insulation, causing a dip in efficiency. Your air conditioner or heater may be working overtime to compensate.

Noticeable Drafts

Drafts of cold air coming in through your windows during the colder months could point to broken window seals. However, drafts can also result from damage to the window frame or the movable sashes in your window, so you should look for other signs of a broken seal to confirm that’s the issue.

Issues With Your Window Frame

If you notice damage to your window frame or you find that your window is hard to open or close, there’s a possibility the frame around your panes of glass has shifted. Since your frame can flex a bit and glass can’t, shifting or even expansion can cause the seal around your glass to break. However, finding frame issues doesn’t automatically mean a broken window seal, so confirm with other signs if possible.

What Causes a Window Seal to Break?

The most common cause of a broken window seal is the natural expansion and contraction of the window materials. Since your windows are exposed to the elements, they’ll naturally see extreme changes in temperature and humidity. As these changes occur, the glass can expand and contract slightly, putting pressure on the seal. As this occurs repeatedly, the seal can eventually fail. This typically only happens after years of exposure.

Since the window seal around your glass is somewhat fragile, the natural shifting of the other window components can also cause the seal to break. For example, natural house settling can cause the framing around the window to shift, warp, and bow slightly over time. Even small movements can cause the window seal to be damaged.

On a more extreme level, foundation issues can cause window seal damage. Since your entire home relies on your foundation for stability, any cracks, water intrusion, and bowing foundation walls can cause the framing to shift unnaturally. This can put excess strain on your windows and eventually lead to a broken window seal. Any foundation concerns should be inspected and handled immediately by a professional, as they can cause extensive damage to your home beyond your windows.

Different Types of Window Seals

The type of window seal used generally depends on the window frame and budget. Common materials are:

  • Rubber: Ethylene propylene diene monomer (EPDM) rubber and neoprene rubber are durable, weatherproof, resist ultraviolet (UV) rays, and provide good insulation.
  • Vinyl: Homeowners can choose between rigid vinyl and flexible vinyl. Rigid vinyl is less expensive, but doesn’t last as long as flexible vinyl.
  • Silicone: Silicone seals are flexible, have strong moisture resistance, and can stand up against the elements.
  • Fiberglass: Woven fiberglass cords can be used with vinyl or rubber to reinforce a seal.
  • Foam: Close-cell foam tapes and open-cell foam rods can provide airtight seals and moisture drainage.

The Best Ways to Repair a Broken Window Seal

If you identify a broken window seal in your home, there are a few different routes you can take to rectify the issue. The exact steps and tools required will depend on the window and the type of window seal you’re using.

Replace the IGU

One of the simplest and least intrusive repairs is to replace the insulated glass unit (IGU). This is a relatively straightforward DIY home improvement project, but it’s best left to experienced DIYers.

You can do this by removing the sash from your window, popping off the window bead used to hold the insulated window glass in place, using a putty knife to break the silicone seal between the sash and the glass, and then removing the glass. You can then remove all of the excess sealant from the frame and install your new IGU with silicone sealant tape and clear silicone.

Read also: Windows Insulation Guide

Get a Full Window Replacement

A more expensive and involved option is to replace the entire window. This is best left to a professional, as it will involve removing the old window, making sure the framing behind it is free from mold, water damage, and excess shifting, and fitting and installing a new window.

This is a great option if you know your window with the broken seal is old or if you’ve found that your home’s energy efficiency has dropped recently. It’s also an opportunity to upgrade your frame materials to something more efficient, like fiberglass.

Make a Claim with Your Window Warranty

If you’re experiencing an issue with a window you installed recently, it might still be under warranty. In this case, your most affordable option is to make a warranty claim. This should cost you nothing, provided the warranty covers the damage you’ve experienced. Your original installer or the window manufacturer should repair or replace the damaged unit for free.

Have it Re-Sealed

You can opt to have the window resealed, which can often be done by a professional in an hour or two. This process involves defogging the window, which means removing all of the moisture from between the panes, and refilling the void with insulative argon or krypton gas before resealing the glass.

This process should not be attempted as a DIY project, as it requires special tools to remove moisture, fill the void with gas, and reseal without letting the gas escape.

In addition to learning how to fix broken window seals, you might also want to know how to repair your window panes when they are damaged.

DIY Vs. Professional Window Seal Repair

Any homeowner who has some experience with DIY home repairs will probably be tempted to fix their broken window seal themselves. While it is possible, it’s generally not recommended.

The seal around your window panes is essential for keeping your home energy-efficient. Any mistakes during the repair could lead to higher heating and cooling bills, an uncomfortable living space, and the need for professional repairs in the end anyway. Additionally, failure to reinstate the seal properly can expose your home to water intrusion. This can lead to severe damage, rot, mold growth, and poor indoor air quality.

Additionally, a professional window repair company will be able to identify if a broken window seal is your real issue, and they’ll be able to diagnose additional issues as well.

All in all, I think it’s best to leave foggy window repairs to a professional. Check out the window contractors below to get help with window repair.

Cost of a Window Seal Repair

If you choose to repair your broken window seal yourself, you could spend as little as $35 in supplies, but keep in mind that larger units will naturally cost more.

If you have a professional come in and reseal the window, you could pay between $75 and $250 depending on the type of window and its size.

If you choose to replace the entire window, you’re looking at an average cost of around $800. However, the price can vary based on the size and type of window. Your total could fall anywhere between $150 and prices well over $1,000.

How to Keep Your Window Seal From Breaking

Thankfully, there are steps you can take to prevent window seals from breaking in the first place.

First, it’s recommended that you choose a high-quality window. Installing a durable window from a reputable brand like Andersen, Pella, or Marvin will always cost a bit more. However, it’s usually worth it because you can avoid issues for years or even decades after installation.

You should also carry out proper window maintenance. One of the most crucial things to do is re-caulk around where the glass meets your frame on the outside of the window once per year. This will help limit how much temperature and moisture changes affect the seal inside.

Finally, you can inspect your windows for damage or difficulty opening and closing about once a year. Finding symptoms of shifting window frames can help identify problems before they become severe enough to lead to a broken seal. You can then address the underlying issue.

Final Verdict: Is a Window Seal Repair Worth It?

Your window seals are responsible for keeping the elements outside where they belong and helping to maintain a comfortable indoor temperature and environment. Not only is repairing window seal failure essential for keeping your family comfortable and safe, but it also helps maintain the energy efficiency of your home. The money you’d spend on repairing your seal will likely be recuperated through lower energy bills.

The bottom line is that repairing a broken window seal is absolutely worthwhile. Even paying a professional to carry out the window repair service for you is recommended over letting the issue worsen, which can lead to reduced home efficiency and expensive water damage.

Frequently Asked Questions

Do broken window seals need to be repaired?

Technically, you could get away without repairing a broken window seal, but it’s not recommended. A broken seal means you’re leaving your home exposed to the elements, so your energy efficiency will drop, your utility bills will increase, and your living space will become less comfortable. It’s always worthwhile to repair a broken window seal as soon as you identify the issue, especially if you live in an area that experiences extreme temperatures.


What are the benefits of repairing a window seal?

Most importantly, repairing a window seal will improve your home’s energy efficiency. Your heating and cooling equipment won’t have to work as hard to maintain your desired interior temperature, which means your equipment will last longer without expensive repairs or glass replacement, and your energy bills will naturally be lower.

Repairing broken window seals also means the outdoor air will stay outside where it belongs. Window seals that are left broken will lead to drafts in your home that make your living area colder in the winter and uncomfortably hot in the summer.

Finally, broken window seals can lead to condensation between the panes that cannot be wiped away. Repairing your seal can mean restoring a clear window, giving you unobstructed views of the outdoors.


Is a broken window seal a big deal?

Yes, absolutely. Broken window seals decrease your home’s energy efficiency and can drive up heating and cooling costs. They can also be indicative of more severe issues, like shifting frames or frame damage. If that’s the case, they can be a sign that your home is exposed to water from the outside, which can cause severe damage and mold growth. Shifting frames can also sometimes help you identify structural damage in your home.


Does homeowners insurance cover broken window seals?

In most cases, no, homeowners insurance won’t cover broken window seals. This is largely because the underlying cause of a broken seal is considered a lack of proper maintenance. Even if your insurance does cover it, it’s best to avoid small claims like window repairs, as these can drive up your monthly premiums.


How long do window seals last?

With proper maintenance, a window seal on a high-quality window can last 20 years or more.


Article Update Log
5/14/2024
Reviewed for accuracy, cost data, industry best practices, and expert advice by Hilary Cairns.
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Dan Simms

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Dan Simms worked in real estate management for five years before using his experience to help property owners maintain their own homes. He got his master’s degree in English Literature and Creative Writing, and he now enjoys sharing his knowledge about homeownership and DIY projects with others on Today’s Homeowner. When he’s not writing, he’s usually outdoors with his wife and his dog, enjoying mountain biking, skiing, and hiking.

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Hilary Cairns

Hilary Cairns is a writer with 12 years of professional writing experience. She has covered a diverse set of topics such as custom home building, plumbing, HVAC, energy efficiency, and others. A graduate of SUNY New Paltz with a bachelor's degree in English and a concentration in Creative Writing, she discovered her passion for helping businesses and organizations deliver impactful content that changed lives. Originally from New York, Hilary now calls Florida home (along with 2 cats). When not immersed in her writing work, she enjoys playing video games, reading Stephen King, and researching her (and her friends') genealogy.

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