A window seal refers to the sealant around the window used to hold in air or gas between the panes of glass. When this breaks, moisture and humidity can build up between the glass in your window, creating a fog inside the windows and decreasing your home’s energy efficiency. This often calls for window seal repair or a full window replacement.

Window seal repair costs $70–$245, but most homeowners spend $120 or under.* However, it’s often better to replace failed window seals rather than attempting to repair them. We’ll cover window seal basics, how to spot damage, and different window seal repair methods.

*Article cost data courtesy of Angi.

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What Are Window Seals?

Single-pane windows are inefficient and are rarely found in newer homes. “If it’s a single pane, well, then you’ve got a piece of glass that’s just keeping the wind and the water and the bugs out,” says Josh Ramsey, regional training manager at Renewal by Andersen Metro Energy & Midwest. “Energy is transferring through it because it’s only going to block roughly 20% of the energy if it’s one piece of glass.”

Today, double-pane windows and triple-pane windows use insulating inert gases such as krypton and argon and come with a low-emissivity (low-e) coating. Insulated window panes are known as insulated glass units (IGU).

Window seals keep these gases in your window, preventing air from leaking. These gases are heavier than air, slowing down the energy transfer between your home and the outdoors. Window seals can save you money on heating and cooling costs through increased energy efficiency.

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How Can You Tell If a Seal Has Been Damaged?

Window seal failure can happen at any time, regardless of your home’s or windows’ age. Here are some signs of window seal damage.

Distorted reflections: When a seal breaks and the insulating gas escapes, the window may may tilt. Over time, this causes a distorted reflection.

Drafty house: Glass panes can shift when there’s no insulation, causing drafts in your home. Try the wet hand test around your windows to check for drafts: wet your hand and run it along the window’s perimeters.

Foggy windows: This isn’t normal window condensation. Without insulation, moisture gets trapped between the window panes, making them appear foggy.

Higher energy bills: According to the U.S. Department of Energy, heat gain and loss through windows are responsible for 25%-30% of residential heating and cooling energy use. Without the insulating gas, your heating and cooling systems will work harder to keep your home comfortable. This could increase your energy bills if you’ve got multiple damaged seals throughout your house.

Difficulty opening/closing: If your window becomes hard to open or close, it could be from a damaged window frame or hardware or from failed window seals.

Colored spots in the glass: If you start to see colored spots in your window’s insulated glass unit, that’s a sign that water has breached the seal.

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Why Window Seals Break

Window seals can’t last forever, and a window seal can fail even if your window is new. If you have painted window frames, using heat guns to remove paint or finish can cause damage. Pressure washing around your exterior windows can cause water to make its way into the window sash and break the seal. Once this seal breaks, krypton or argon gas between the panes will leak through sealant cracks. Here are some of the most common reasons for window seal failure:

• Solar pumping: Solar pumping, or thermal pumping, is a natural condition where the sun heats the space between the glass panes and causes the gas to expand, putting pressure on the panes. When it cools down at night, the space contracts. This constant cycle causes the window seal to break.
• Old window seal: Window seals can last up to 20 years, depending on how well you maintain your windows, where you live, and other factors. After a decade, you may need window seal repair or even window replacement if your windows are old and in bad shape.
• Poor maintenance: Following the manufacturer’s care instructions can help prolong your window seal’s life. Most manufacturers suggest keeping seals dry and using recommended cleaning agents.
• Extreme temperature changes: Window seals can take some pressure, but prolonged extreme temperature changes cause seals to expand and contract. This eventually leads to the seal breaking.
• Harsh weather conditions: In coastal areas or regions with high humidity, water can make its way between the glass panes and cause mold, rot, or rust.
• Poorly fitting window seal: If a window seal isn’t correctly fitted or comes away from the surface, it won’t work as it should. This can happen if it’s cut too short or if there’s grease on the seal’s backing from hands or tools.

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Best Window Seal Repair Methods

There are several options for repairing or replacing a window seal. The method you choose depends on your windows’ condition, the damage, and the type of seal repair required. We’ve outlined the best options in the dropdown sections below.

Use Your IGU Replacement Coverage

Check your windows’ warranty for IGU replacement coverage. Your warranty coverage depends on the manufacturer and the window quality. For example, lower-cost replacement windows may only have warranty coverage for a few years, while higher-quality windows could include a warranty of up to 15 years or longer. If your window is covered, you’ll have minimal out-of-pocket costs for IGU replacements.

Call your window manufacturer to verify coverage and request an IGU repair or total replacement. The manufacturer will send their own pro to do the job, or they’ll ship the IGUs and you’ll handle the repair or find an installer.

Pay For IGU Replacement

IGU replacement is affordable even if you have to pay for it yourself. Contact a professional contractor to schedule a repair day. You can ask the contractor for IGU replacement options or contact your window manufacturer for IGU replacements available at local glass shops.

Have Your Windows Defogged

You can hire a professional contractor to defog your windows. This process involves drilling a tiny hole in the glass and pumping a chemical inside to dry up moisture. The installer uses a vacuum to remove as much air as possible and then seals the hole.

Foggy window repair is a temporary fix. If you don’t repair your window seals, the fogginess will return. If you have glazed windows without gas between the panes, you can have them resealed. If you have gas between the panes, you must replace the IGUs.

Get a Full Window Replacement

Replace your windows if there are other problems besides a broken seal, such as damaged frames or warped glass. This will help you save money on energy bills in the long run. To improve your home’s energy efficiency, look for double- or triple-pane replacement windows with insulating gases.

Check out the video below to learn some cost-effective ways to seal and insulate existing windows without replacing them.

https://www.youtube.com/watch?v=heizjoK2cHAu0026pp=ygUcY2F1bGsgd2luZG93cyB0aGlzIG9sZCBob3VzZQ%3D%3D

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DIY vs. Professional Window Seal Repair

Window seal repair may sound like an easy do-it-yourself (DIY) job, but a single mistake could damage your window further and cost you extra money.

A professional window repair company ensures high-quality window seal repair and warranties that cover any necessary future repairs. By doing the work yourself, you won’t have access to warranties and could unintentionally void any current manufacturer warranties associated with your old window seal.

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Our Conclusion

Failed window seals directly impact your windows’ visibility and efficiency. We recommend contacting a local professional to do this home improvement project instead of taking it on yourself. The right window seal repair method depends on the extent of the damage and the window’s condition. Defogging may help, but it doesn’t take the place of window seal repair.

Check your windows’ warranty coverage to see if it covers IGU replacement or a full window replacement. Compare quotes from at least three companies when looking for the right professional to do the job.

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Window Seal Repair FAQ

Is it possible to reseal double pane windows?

It’s possible to reseal double pane windows only with glazed windows without inert gas insulation. This involves stripping away the old seal or gasket and placing a bit of silicone caulking in the corners of the window sash to seal the new gasket to the sash. If there’s insulation between the glass panes, you only have to replace the IGU with the broken seal or the entire window.

Do you need to replace the window if the seal is broken?

No, you won’t always need to replace the window because of seal failure. You can swap out the old IGU with a new unit. If you notice extensive damage or your windows are old, consider getting a window replacement.

What are the effects of a broken window seal?

A failed window seal allows moisture to seep between the glass panes. Not only does this affect window visibility, but it also causes the inert gas to leak out and decrease energy efficiency. This can lead to drafts and higher energy bills.

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