Defog your window and see clearly again
If you notice that your windows are too foggy to enjoy the view outside, there are a few routes you can take to repair them. A properly insulated window should prevent fogging, but when the seal fails, air gets between the panes, and moisture gradually builds up. Use our guide to learn how to fix foggy windows in your home.
It’s common for double- or triple-pane windows to collect moisture between the panes when the seal fails, making the window fog up. Seals can break because of old age, exposure to water, or big temperature changes. As a result, moisture and calcium deposits build up between the panes and etch into the glass.
Luckily, you can learn how to fix foggy double-pane windows and triple-pane windows to restore them to their original glory—or you can replace them with newer versions.
You have a few options to fix foggy windows. The quickest fix is to simply clean out the trapped fog using a cleaning solution. But for longer-term fixes—particularly if the window is damaged—you’ll need to replace either part or all of the window.
Suppose the window sealant is not entirely damaged or you want an effortless fix for your foggy windows. In that case, defogging the window in place can be an effective fix for double-pane windows without doing major work.
While this method is affordable for removing the trapped fog in double-pane windows, it is only cosmetic. It doesn't replace the inert gas between the panes or restore the window's heat efficiency. Because you’ll be drilling into the glass, be sure to wear safety goggles, a dust mask, and heavy gloves to protect yourself in case of broken glass or glass dust.
Follow these steps:
Drill Holes in the Glass: Drill tiny holes at the top and bottom of the window in the outer pane of glass. Use a carbide-tipped drill bit to avoid breaking the glass.
Add a Drainage Tube: Use caulk to attach a plastic tube to the lower hole. Allow the caulk to dry completely before going to the next step. Most caulk requires 24 hours to dry.
Clean the Inside of the Glass: Using the upper hole, add a cleaning solution to the interior of the panes of glass. You then can add a spray rinse solution through the same hole to finish washing the glass. As the solutions run down the glass to the bottom, they should drain out of the tube.
Remove Remaining Moisture: Using the upper hole again, add a drying agent to the interior of the window, removing any remaining moisture. Then add an anti-fog coating.
Reseal the Holes: After adding these agents and coatings, seal the holes in the window immediately. If you wait, you could allow damp air to re-enter the space between the panes. Clean the holes before covering them with a special air sieve that prevents dust, insects, and moisture from entering.
| Pros | Cons |
|---|---|
| No window removal | Requires special DIY skills |
| Inexpensive option | Only a cosmetic fix |
| Quick process | Could break glass |
If the seal fails, your window will never be thermally efficient unless you reseal it. If you don't repair the sealant, it's only a matter of time before your window gets foggy again.
Replacing the window sealant is usually more affordable than total window replacement because they require less labor and fewer parts. Repairing a faulty window sealant costs anywhere between $70 and $250.
These are the steps to add new window sealant:
Dismantle the Window: First, remove the window trim. Then pull the panel out using a suction cup. Next, take the panel apart. Use a razor blade to separate the glass and the sealant, but do so carefully to avoid breaking the glass.
Clean the Glass: Clean the glass by removing any residue remaining from the sealant. Then remove dust, streaks, and other contaminants with a glass cleaner.
Replace the Silica: Trim the sealant away from the frame, gaining access to the area that stores the silica beads. Place fresh silica beads into the space to help with moisture absorption after you put the window back together.
Reassemble the Window: Put the panes back inside the frames and caulk the edges of the window sashes. Allow it to dry, which may take about 24 hours, before removing excess caulk.
Apply Sealant: Finally, apply a window seal, adding a thick layer at the corners. Allow everything to dry before putting the panel back in place and securing it.
| Pros | Cons |
|---|---|
| Restores temperature control | Challenging DIY job |
| Cheaper option | Lengthy process |
| Immediate benefits | Breakage is common |
Almost all modern windows are insulated window units or IGUs. IGU means ”insulating glass units,” which refers to the sealed part of the window with two or more panes of glass and gas between the panes.
In reality, all IGU units gradually lose the inert gas in the space between panes, and the sealant themselves wear down in time. Persistent fogging and drafts are signs that the IGU’s seal has failed.
You can often replace the IGU without replacing the entire frame. Most high-quality windows come with a 20-year warranty at the time of purchase for glass seal failure. Replacing an IGU is a difficult task to DIY, so it’s best to hire a pro to ensure it’s done safely and correctly.
| Pros | Cons |
|---|---|
| Renews inert gasses | Difficult DIY job |
| Cheaper option | Few pros do this job |
| New warranty period | Time-consuming work |
If your window is more than 20 years old, the glass is cracked, or the frame is rotting, you should consult with a local window repair professional to evaluate if you need to replace the window.
The typical window replacement cost is about $750 per window. Investing in high-quality windows won't only solve fogging problems. It’s also a great way to make your home more energy-efficient and enhance aesthetics.
If you choose to try to do this work yourself, you will need to learn how to measure for replacement windows because precise measurements are vital to a successful project.
| Pros | Cons |
|---|---|
| New window warranty | Priciest option |
| New design features | Creates waste |
| Common job for pros | May not match others |
If you recognize signs of window fogging happening in your home, there are ways to prevent it from progressing to needing to repair or replace it. Follow these tips for preventing your windows from fogging up.
Upgrading your older windows to newer, more energy-efficient windows can help reduce heat loss and, as a result, make your windows less foggy. If you don’t want to replace your windows entirely, you can also weatherstrip your current ones to make them more efficient.
By running a dehumidifier near the window, you can reduce some of the moisture in the air that could be causing the foggy double-pane windows. Using the dehumidifier is a good idea for a kitchen window that fogs when you cook and boil water on the stove, for example.
Something as simple as installing a plastic film over the window can help cut down on condensation. It blocks the home’s moist, warm air from reaching the glass.
If you have ceiling fans running in the area, they will move moist air around the room rather than leaving it to collect in the area near the windows.
When your windows aren’t installed correctly, the seals within the panes can break, letting moisture inside. Fixing foggy windows in the long run may just be a matter of calling in a specialist to do everything for you. If you aren’t confident in your DIY skills, it’s a good idea to hire a pro to handle your window installation.
To prevent foggy windows, you should check your windows for cracks and gaps regularly, but it’s especially important to inspect them after a big storm or heat wave. These extreme elements can put pressure on your windows, causing them to break or wear down and, potentially, fog up.
While it’s possible to fix a foggy window on your own, hiring a professional always ensures the job is done correctly and safely. Contact a window repair professional to tackle the defogging process, or hire a local window replacement specialist to remove the current version and install a new one. The pros can also assist you with choosing the best replacement windows for your needs.
Yes, you can use a defogging spray on your windows. However, these types of products are more temporary solutions, and you may notice the fog coming back after you’ve used the spray. To fix your foggy windows for good, you’ll need to figure out what’s causing the problem (whether that’s damaged insulation or a broken seal) and address the issue accordingly. Call in a pro if you can’t diagnose the problem on your own.
A handy hair dryer will quickly remove condensation from your window, but it’s only a temporary fix. The hair dryer maneuver will not repair the root of the window fogging problem, which is likely a broken window seal. If you need to defog the window quickly, such as if guests are coming over, use the hair dryer. However, for a permanent solution, defogging the window or replacing it are the only options.
In order to lower your home’s humidity level overnight, you can open your windows when the air is less damp. This tactic allows air to circulate around the window, preventing condensation from forming. However, you should consider the disadvantages of leaving your windows open overnight, including safety risks and pest intrusions.
