Keep cool and clear away condensation with these fixes
Condensation happens when the air outside is a different temperature than the air inside.
Condensation may be a sign of a faulty window seal.
It could also mean your home needs ventilation improvements.
One quick fix is to open up the windows in the house to equalize the temperature.
Condensation should be dealt with quickly to avoid mold growth.
Foggy windows are a nuisance for many homeowners who want to restore the beautiful clarity of the glass, but there’s a difference between a little fogginess and condensation. Condensation on the inside of windows happens when moisture forms on the glass because of temperature differentials between the indoor and outdoor air.
This issue is both cosmetic and functional, as it can affect your window’s ability to insulate and even lead to water damage. But don’t fret—it’s not difficult to fix. Here’s what causes window condensation on the inside of windows and how to fix the issue.
In some cases, simply opening your windows to let outdoor air in will fix the issue. Condensation on the inside of windows forms when moisture in the air condenses on the glass. The reason this is commonly attributed to temperature differentials between the outside and inside air is that warm air holds more moisture than cold air. If warm, humid air suddenly drops in temperature, the moisture naturally falls out because the dew point is lower.
Opening your windows can fix this problem in a few ways:
It lets indoor humidity escape. When you open windows in a home that’s warmer than the outside temperature, the warm air rushes out and brings some of that humidity with it. Reducing the humidity level will leave less moisture in the air to condense on the glass.
It reduces the temperature in your living space. Similarly, that rush of warmth outside will bring cool air in, reducing the temperature inside. When the temperature differential on either side of the window is balanced, there’s less chance of moisture condensing on the glass.
It introduces ventilation. Opening windows creates air movement inside, and moisture evaporates more readily in moving air.
Since indoor humidity is sometimes to blame for condensation on your windows, bringing down the humidity will leave less moisture in the air that can condense on the glass. There are several ways you can bring down humidity levels in your living space:
Install a dehumidifier
Reduce how often you cook on an open stovetop
Take cooler showers and run the bathroom exhaust while showering
Provide adequate ventilation in home exercise areas to get rid of moisture from perspiration and heavy breathing
Turn on ceiling fans or whole-home vent fans to circulate air
Another way to stop condensation on the inside of windows is to lower your thermostat settings. The risk of condensation on the inside of windows is higher when the temperature difference on either side of the glass is larger. If you can drop the indoor temperature a few degrees and still maintain comfort, this might solve the issue or at least make the condensation less severe.
Aging windows can gradually lose their ability to insulate because of broken seals around the panes. Most modern windows have two or three panes of glass with a layer of insulating gas sealed between them. The gas prevents the cool outdoor air from touching the warm layer of glass inside.
Some older homes have single-pane windows, which used to be the standard before the 1970s. Single-pan windows aren’t nearly as energy-efficient as double- or triple-pane options and provide a single layer for outdoor and indoor air to mix.
Replacing aging windows is a good way to improve insulation that can help avoid condensation.
A broken seal around a pane of glass will allow moisture in the air between the panes, which can get trapped inside. This not only creates potential problems with fogginess on your windows, but it also means the layer of insulating gas has escaped, leaving your window far less energy-efficient.
You can hire a professional to fix a window leak and re-establish the seal for you if you want to avoid a total window replacement.
The other option, of course, is replacing the window. Most window companies will be able to perform a window seal repair, but if you know your windows are reaching the end of their lifespan or want to upgrade anyway to boost home efficiency, replacing the window might be a better option in the long run.
You should talk to a window repair professional near you about whether to repair vs. replace a window with a broken seal. A professional will be able to advise you on the best route..
Condensation on the exterior of windows is common in summertime when hot outdoor air comes into contact with windows that are cold from interior air conditioning. You can help balance out the temperature differences by setting the AC at a higher temperature or even opening the window to let some warm air inside.
If you’re not keen on warmer interior temperatures but still want to avoid outside window condensation, spray a water repellent on the outside surface of the glass and wipe it clean. You’ll have to reapply it regularly as part of your routine window maintenance to keep the glass clear, but it’s an easy way to stop condensation on windows.
Most products made for car windshields should be safe for home windows, too, but you might want to speak with a local window expert to confirm before using them.
Fixing condensation on a window can range greatly in costs. You can open a window for free, or you can set up a portable dehumidifier in a room for anywhere from $20 to over $300, depending on the model you choose. If you notice high humidity is an issue all over the house, a whole-house dehumidifier costs between $1,300 and $2,800.
If the issue is your window seals, window repair costs about $120, on average, with most homeowners paying between $70 and $245. This repair can reduce condensation, improve your home’s energy efficiency, and fix drafty windows all at once, so it can be worth it to hire a window repair professional for this solution.
For more extensive damage to the window or seal, or if your windows are reaching the end of their life anyway, you’ll likely need to install new windows. Window replacements cost about $280, on average, or between $100 and $800 per window. If you see signs of mold growth or water-damaged building materials when you notice condensation or during window repairs, you could pay a few hundred dollars more to replace the materials and for the cost of mold remediation.
Paige Bennett contributed to this piece.
While condensation on the inside of your windows occurs naturally, most often because of higher temperatures inside than outside, you should be somewhat concerned for two reasons. First, excessive condensation can drip down the glass and damage building materials below, which can be expensive to repair if left unfixed for too long. Second, it could be a sign that your windows aren’t insulating your home properly, possibly due to a broken window seal. In either case, you should address the problem quickly to avoid property damage and high heating and cooling bills.
Keep your home’s interior temperature around 68 to 70 degrees Fahrenheit to prevent condensation on the windows. You might need to adjust that up a little in the summer months if it’s excessively hot outside or down a few degrees in the winter to bring down the temperature differential on either side of the glass. More importantly, you should keep the humidity levels inside below 60%. Keep humidity at around 30% in winter and 50% in summer. Many smart thermostats will also measure indoor humidity, but you can also check the levels with a hygrometer.
Both hot and cold air help get rid of window condensation, depending on which side of the glass the warm air is on. In the summer, increasing the temperatures inside can help increase the temperature of the glass window and reduce outside window condensation. Lowering the indoor temperatures in the winter can help lower the temperature of the glass and create a better balance between indoor and outdoor temperatures. The differences in temperatures inside and outside the home are what cause the condensation.
