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Fixing Foggy Windows

Foggy Windows

Gazing out at the view from your double-pane windows and watching the fog roll in can bring up beautiful memories of San Francisco Bay or the streets of London. But seeing foggy windows in your home isn’t just a side effect of humid weather—it’s usually a sign that something’s not right. The moisture that creates foggy double-pane windows is almost always caused by a break in the window’s seal. It condenses into water droplets and can cause mold growth and damage to your windowsill. It might even affect the carpet and floors below the window.


Why does my house have double-pane windows?

Double-pane window panels are known in the glass industry as an insulated glazing unit or insulated glass unit (IGU). Homebuilders and energy-efficiency experts recommend them because they keep your home so much better insulated than single-pane windows. When the windows are constructed, dehumidified air or an inert gas is sealed between the two panes. Each panel is typically sealed with a chemical called polyisobutylene. This forms a barrier that prevents your house from losing heat in the winter and cooler air in the summer. The extra insulation conserves energy, saves money, and reduces your carbon footprint.

Why do seals break?

In ideal conditions, double-pane windows are built to last. The typical lifespan of a double-pane window is roughly 10 to 20 years. But if you have an older home, some of your double-pane window seals will come to the end of their natural lifespan and start to fail. If you have a newer home, factors like direct sunlight, pressure washing, and weather damage can affect the lifespan of your window seals.

Plus, while single-pane windows have just one seal, double-pane windows have two— an inner seal that protects against moisture and corrosion, and an outer seal that reinforces the strength of the window frame. As a result, it doubles the chance that a seal will fail.

Why does a broken seal cause a foggy window?

It has to do with the way IGU windows are constructed. Most have a rubber tube called a desiccant placed between the panes of glass, to help keep the air inside dry and at a constant temperature. But when the polyisobutylene seal is broken, air from the outside seeps into the space between the glass panes. With that air comes moisture that overwhelms the desiccant. It condenses into water droplets—especially if the glass pane on the outside is colder than the pane on the inside—and your windows start to develop a haze or fog that comes and goes with the weather.

Can double-pane windows be resealed?

Some companies, and even some DIY kits, offer services that claim to get rid of the window fog without replacing the window or even restoring the sealed window spaces. They drill holes in the glass, vacuuming out debris, and install micro-vents to ensure air ventilation. This method can give you clearer windows but unfortunately, it doesn’t last. More importantly, this method causes you to lose the energy efficiency advantage that your double-pane windows provide.

For this reason, it’s usually a good idea to find a professional to help with your foggy windows. If the window can be repaired, glass professionals will do their best to save the window and just replace the glass. But if the window must be replaced, you can be sure they’ll deliver the advantage of their expertise.

Finding a professional to fix your panes

Before calling in a pro, check to see if your windows are still under warranty. Premature window seal failure may entitle you to compensation that covers some or all of your window replacement. In fact, DIY repairs might void the window’s warranty, so hiring a professional could be the only way to ensure compensation. But even if your double-pane windows are coming to the end of their lifespan, hiring a professional to replace them can still save you time and money.

An experienced team of professionals like the ones at Glass Doctor can come to your home and evaluate what kind of work needs to be done. Their skilled technicians will determine if you just need to replace the glass panes, or if replacing the entire window frame is necessary. No matter what your glass needs are, they can help stop those foggy windows from disrupting your view. Call (833) 974-0209 or request an appointment online to get started.