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Can you reseal double-pane windows?

What are double-pane windows?

Many homeowners are upgrading to double-pane windows. As their name suggests, this type of window features two panes of glass, instead of just one. The main advantage of double-pane—also known as “dual-pane”—windows is their energy-efficiency. Thanks to an insulating air pocket between the glass panes, double-pane windows vastly improve your cooling and heating efficiency.

Due to age, improper installation, or a number of other factors, the air pocket seal in dual-pane windows can fail, allowing the insulating gas to escape and moisture to become trapped between the panes. This causes window fogging and greatly reduces the efficiency of your windows. In this article, we’ll review everything you need to know about repairing, resealing, or replacing your double-pane windows.

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If you have water damage from condensation inside your window, you might want to consider seeing clearly again by replacing the glass.

Why are my double-pane window cloudy?

The two panes of glass in a double-pane window are actually separated by a thin interior air pocket. When the windows are manufactured, this pocket is often filled with a non-toxic, insulating gas—like argon or krypton—and then sealed tight. The seal plays two key roles: first, it prevents the insulating gas from escaping. But, it also prevents outside air and moisture from getting into the air pocket.

If your home’s double-pane windows are clouding or steaming up between the two panes of glass, that’s a good sign that the interior air pocket has been breached, the insulating gas has escaped, and that moist air is entering into the gap.

Most dual-pane windows contain desiccant beads. These are moisture absorbers: the beads will dry out the air inside the air pocket after the window has been sealed. They can also handle incidental amounts of moisture shortly after the seal is breached. However, there’s an upper limit to how much moisture and condensation the desiccant beads can handle, which is why your windows are now clouding up.

This before-and-after image shows how replacing the window cleared up the fogging problem.

Are broken window seals a big deal?

Yes. Without its insulating gas in the sealed air pocket, your window loses a great deal of its energy-efficiency. As condensation enters the air pocket, your windows will start to fog up from the inside. Difficult to clean, this makes your windows—and your home—a lot less appealing. For homeowners who are thinking about listing their homes in the near future, this can be a source of frustration.

That efficiency loss is quantifiable, too. The energy-efficiency of window glass is measured by its r-value—essentially, how well it slows the transfer of heat energy. In the summer, this means rejecting heat energy from the sun; in the winter, it means retaining heat energy generated by your home’s furnace. With insulating gas, many double-pane windows can reach an r-value of 6. However, without that sealed air pocket, their r-value drops to 1 or 2. On its own, glass is not very effective at slowing the transfer of heat energy.

Can foggy double-pane windows be repaired?

While there are several ways to temporarily de-fog your double-pane windows and attempt to block out further moisture, there’s no such thing as resealing a double-pane window or restoring its original energy-efficiency. You’ll need to replace the window instead.

Defogging a window can be tricky—after all, there’s no easy way to wipe away the moisture or condensation as you would on the exterior sides of the glass. One potential solution is adding more desiccant. Typically sold in packets, this moisture-absorbing substance will eventually dry out the air inside of the air pocket, removing the moisture. It’s only a temporary fix, however: eventually, the desiccant absorbs as much moisture as it can before more gets between the panes of glass.

What’s it cost to reseal double-pane windows?

In most cases, repairing a window seal will cost you between $70 and $150 per-window. The cost of repairs will be higher if you need glass replaced, moisture removed, or the sash repaired, as well. You’ll want to talk to a window professional to get a comprehensive quote for your exact situation.

As previously discussed, resealing a double-pane window rarely restores its original energy-efficiency. You’re probably better off investing in a new window. While the upfront cost is higher (on average, $170 – $250 per-window), you’ll save more money in the long-term through lower heating and cooling costs.

Again, talk to an expert: your exact costs will depend on where you live and what kind of windows you have. They’ll help you weigh the pros and cons of window repair versus window replacement.

How long do window seals last?

Your home’s double-pane windows and their seals should last about 20-25 years. However, their lifespan greatly depends on the quality of the window manufacturing process and initial installation. Premature seal failure can occur if the windows are improperly installed in hot weather, or if water damage affects the window sill.

You can avoid future window seal problems by having high-quality windows installed by a reputable company. Many homeowners run into issues when they try to cut costs: they buy cheaper windows from a less-reputable manufacturer, or have an inexperienced technician install them. Poorly made windows tend to have weak seals.

Perhaps most telling is that they often don’t come with a manufacturer’s warranty. You can tell if a double-pane window is reputable if the manufacturer is willing to stand by their product for 15-20 years after installation. Your windows should be warrantied for at least that long. That way, if you do run into seal problems, you can get them replaced under warranty.

Can you replace just one pane?

Let’s say your issues are less with the seal, and more with the window pane itself. An errant baseball pitch cracks or shatters the exterior pane of glass. Unfortunately, it’s not as easy as just replacing the broken pane. The air pocket of your double-pane window has been breached, which means its energy-efficiency is now compromised. Even if you have a new exterior pane installed, your dual-pane windows will never be as efficient as they once were.

The better solution is to have both panes of glass replaced, so that your home doesn’t lose out on energy savings. Talk to a window or glass specialist to get an individualized recommendation.

Who should I talk to about my windows?

If you’re noticing signs of window fogging in your double-pane windows, you’ll need to talk to a window or glass expert in your area.

At Residential Glass, we help Pittsburgh homeowners with their glass and window replacement needs. Call us to get a free quote.