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Condensation on windows may not seem like a big deal, but it can point to a larger issue or lead to one if not treated. At the least, it’s an annoyance that impairs your view. Below, we look at three reasons window condensation forms and how to get rid of it.
What Causes Condensation on Windows
Condensation happens when one side of a surface is a much different temperature than the other. The moisture happens on the more humid side of the surface—usually the warmer side. For example, if your home is cold and the morning sun hits your window, you could see condensation develop if the window’s interior glass is cold enough and the sun’s rays are warm enough.
This is normal and typically not a significant issue, but it’s important to pay attention to where and how condensation on your windows occurs to determine if there’s a larger problem.
Exterior Window Condensation
Condensation on the outside of your windows is expected, since it’s typical for the outdoors to be humid. This happens most commonly in the morning, and the sun will evaporate the moisture by midday.
Condensation Between Window Panes
If you have double- or triple-pane windows and spot condensation between the panes, this is likely an issue with your window’s seal.
Interior Window Condensation
Condensation on the inside of your windows can point to a problem. This is a sign that it’s more humid in your home than outside. According to the Environmental Protection Agency (EPA), your home should have a humidity level no higher than 60% and no lower than 30%. Ideally, your home’s relative humidity level should be closer to 30% in the winter months and 50% to 60% in summer. Most modern thermostats have a humidity meter built in, but if yours doesn’t, you can buy a humidity meter online to see what your level is.
Homes that are too humid can develop or already have a mold and mildew issue, and it may not be visible. Mold can develop behind walls, in your ceiling, and in your crawl space. Note whether your window condensation happens regularly and whether it’s on every window or just in a particular room.
If interior condensation only happens in rare instances, such as extended oven use on Thanksgiving day, it’s probably not an issue. If your home’s windows show condensation on a regular basis or only in a certain room, we recommend trying one of the methods outlined below.
How to Get Rid of Condensation on Windows
The best method to get rid of condensation on your windows depends on whether the condensation occurs on the outside, inside, or between the panes. Here’s how you can prevent condensation based on your issue.
These are the best options for eliminating outdoor condensation:
- Applying a water repellent
- Trimming foliage
- Raising your home’s temperature
Condensation on the outside of windows isn’t a problem for your health or home maintenance, but if you don’t like how it looks, you can spray a windshield water repellent, such as Rain X, on the outside of the window. A water repellent will encourage droplets to form and run off the window.
You may also want to consider trimming the shrubbery around your windows. This will increase air circulation and allow the sun to hit the window so it can evaporate any moisture.
If you don’t mind keeping your home a little warmer, not running your air conditioning as much in summer can help balance interior and exterior temperatures so condensation doesn’t develop.
Condensation Between Panes
If you only experience condensation between window panes, the problem is typically a faulty seal. You can fix that by replacing the insulated glass panel, which is low-cost and something you may be able to do yourself if you’re handy.
Reducing condensation on the inside of windows is all about lowering indoor humidity. Here are a few ways you can do this:
- Running a fan
- Lowering your humidifier
- Opening curtains and blinds
- Cracking a window
- Removing plants and firewood
- Replacing your windows
Running fans is a simple way to increase air flow and lower air moisture. This could be via portable or ceiling fans, or exhaust fans in your bathroom and kitchen while showering and cooking.
Reducing your humidifier usage or getting a dehumidifier is another way to get your home’s humidity level back in the optimal 30% to 60% range.
Opening your window treatments prevents heat buildup between the window glass and curtains or blinds. This helps reduce humid air around the window. You can also open windows for further ventilation.
Natural items such as houseplants and firewood release moisture regularly. This is common if you keep plants on your windowsill. Consider reducing the number of houseplants you have, or at least moving them away from windows to well-ventilated areas. Keep firewood outside if you can.
If you have old windows, they may just need to be replaced with modern, weatherized windows. Modern windows are made with weatherized glass and are installed with weatherstripping to create a tight seal. New windows perform better in different temperatures and reduce how much moisture forms while also lowering your energy bills. See our list of the best replacement windows.
Professional vs. DIY Window Maintenance
One of the methods above will likely resolve any excess moisture issues you have. If not—or if you suspect your home has a more severe issue with excess humidity that’s causing mold or water damage—we recommend calling a professional. Home inspectors are trained to spot hidden sources of moisture in all areas of your house. A home with especially moist air doesn’t just cause issues with your windows but with your walls, attic, foundation, flooring, roof, and other areas. The condensation on your windows could be what’s most visible, but there could be a larger moisture problem behind the scenes you need to resolve with a pro.
Exterior condensation isn’t a problem for homeowners aside from appearance. Interior condensation or moisture trapped between panes of glass needs to be addressed. You can likely resolve minor condensation issues by increasing air circulation, but if your home has an ongoing issue with high humidity levels, call a home inspector to check the cause of the moisture and ensure you don’t have mold or damage.
If you’re in an older home, the best fix may be investing in more efficient windows that are designed and installed to regulate air temperature. See our guide to window replacement costs if you think this is the right route for you.
Window Condensation FAQ
How do you stop condensation on windows?
How you stop window condensation depends on whether the condensation is outside or inside the glass. You can eliminate condensation on the outside of your window by applying a water repellent, trimming shrubbery around the window, or increasing your home’s temperature. Get rid of condensation on the inside of your windows by increasing ventilation through a fan or dehumidifier.
Why am I getting so much condensation on my windows?
Condensation on the outside of windows is normal and is caused by outdoor humidity. Condensation on window interiors is due to high indoor humidity levels, which can be a cause for concern if it leads to mold or water damage.
Is it okay to have condensation on the inside of my windows?
You shouldn’t have frequent condensation on the inside of your windows. This is a sign that your indoor humidity level is too high, which can lead to mold and mildew behind your walls, in your crawl space, in the attic, or under flooring.
Is condensation on windows a problem?
Condensation on the outside of windows isn’t a problem. Condensation on the inside of windows is a sign of a humidity issue in your home that should be addressed to protect your home and your family’s health.