10 Ways to Reduce Window Condensation (to create a healthy house)

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Easy steps to reduce window condensation and improving the indoor environment

Often times I work with homeowners who aren’t 100% sure how taking care of a home can help create a positive indoor environment.  They might know the basics, like keeping it clean, but they many times ask me HOW they can make their space healthier. Obviously there are so many aspects of home maintenance and care that come into play, but one I like to give a decent amount of focus to is windows.  And more specifically, I like to talk about windows in terms of the condensation that forms on the interior.

You may be wondering WHY this has anything to do with a healthy house, but the truth is it has A LOT to do with the indoor air quality inside.

If windows continually have condensation sitting on the sill, whether it be wood, vinyl or aluminum, the water creates a ripple effect in the quality of indoor air.  First, the water sitting on the sill is damaging to the window casing. If it’s a wood window, you may notice the stain and varnish start to deteriorate rather quickly.  Once that protective varnish is gone the risk of damaging the actual wood becomes very serious.

Wood is a natural food source for mold, and once mold has started on the window it can become nearly impossible to completely remove it.  The maintenance that’s involved in wood windows that have condensation can be a long, tedious set of tasks.

The second way that condensation on windows affects your home’s health is by the water on the window raising your indoor humidity.  If you’ve been around my site you know that indoor humidity can affect things like dust mite reproduction, mold growth and toxin off-gassing and the overall health of your indoor air.  When indoor humidity is too high, the negative effects on the indoor air quality begin to take place.

So you can see that keeping condensation off of windows, especially in bathrooms and bedrooms is extremely important to the health of a home’s indoor environment.  But how can you stop this from happening? Below are 10 easy, inexpensive ways you can try to fix the condensation on your own windows.

Use Vented Fans

This is a must when it comes to cooking and bathing.  Just these two daily occurrences can increase the overall humidity in your home.  If you have a master bathroom, it can REALLY affect the humidity levels in your bedroom.  The water vapors quickly travel to where the air is dryer. Once humid air hits a cold surface like a window, it turns to condensation that takes quite some time to evaporate.

HEALTHY HOUSE TIP:  Make sure all bath fans are properly vented out the roof by popping your head into the attic and making sure the vent pipe has not fallen down.

Healthy Laundry Habits

Again, this is a point about adding moisture to the air inside your home.  Your laundry habits, whether it be line drying indoors or using a dryer that doesn’t vent to the exterior of your home, can add a lot of moisture to the laundry room as well as the rest of the house.  Checking to make sure your dryer is in fact vented to the exterior and that the vent is not blocked by lint will help ensure that most of the moisture is being expelled outside. Also, line drying inside can raise your overall indoor humidity by a whopping 7%-12%.  If you MUST line dry, do it near an open window or use a fan of some kind to help.

No Over-watering

While we’re on the topic of humid air affecting the window condensation in your home, make sure to check your plants (how many, location, etc.).  Plants are a great source to add moisture to a dry area as well as other benefits to our health and wellness. But over-watering plants or too many plants in general can cause a large increase in indoor humidity levels.  And if the plants are right next to the windows, I’m sure you can guess that they’d be more likely to cause window condensation from the humidity near the window area.

Switch Out Your Humidifier

Many homes in the northern half of our country use humidifiers all throughout the winter.  While these are imperative to some health ailments, they can be problematic if you start to see condensation forming on the inside of windows. If you feel like a humidifier is the culprit, but you still want to use one, I suggest switching over to a cool mist vaporizer.  This should allow you to get a little relief from dry air, but also prevent that window condensation as well. Or try turning it off for a while and see how your body does. The humidifier can always be turned back on later.

Warmer Indoor Temperatures

The science behind condensation forming on the interior of windows is that once warm, humid air comes in contact with a cold surface like a window, or sometimes even a wall, the moisture from the air forms condensation on the surface it touches. With this in mind, you can try to warm up the temperatures INSIDE your home, which will then in turn warm up the window surfaces.  You may also notice that the windows on the south side of your home don’t have as much condensation in the winter. This is because the surface of the window is warmer.

Space Between Shades


The better the air flow around the window, often times the less it condensation has a chance to form.  The reason is twofold, in that the air circulation helps any water forming evaporate more quickly, but it also prevents the moisture forming in the first place due to regulating the temperature of the window.  Keeping a space between the window and a drawn shade can help keep air flowing around the actual window pane. This is the reason often times we see condensation in the morning, after the shades have been drawn all night, insulating the window from the warm interior air.

Ceiling Fans

Using a ceiling fan can be a great way to keep the air circulating in the room and keeping the interior air warmer and a bit more dry to prevent moisture from forming on the window panes.  You’ll want to make sure the fan is rotating clockwise in the winter. This will help push the air off the ceiling and back to the floor, keeping the entire room warm. This is an easy change to make and try and often times one of the first things you might do, especially if the condensation is localized to one or two rooms.

No Furniture Under the Window

If you have a couch or bed pushed right up against the wall directly below the window, you may be interfering with the natural air flow of the warm air near the window. It’s the same idea behind keeping a space between the window and whatever blind or shade you’re using.  The less warm, dry air that is around the window, the more condensation you may see forming. Leaving just a small space between the wall and furniture to allow air to flow and move is beneficial and an easy thing to try.

Weather Stripping

Weather stripping either on the window or the window sash can help prevent cold air from leaking into the house, which can change the temperature of the window on the inside.  Again, we want to keep the window on the inside of your home the same temperature as your indoor air to prevent condensation from forming. Weather stripping can be as easy as a foam adhesive strip you can add, or it can be as complex as adding a bead of caulking to the corners and edges.  Either way, finding some quality weather stripping can help prevent condensation on the interior of your windows.

Ventilate for 5 Minutes Per Day

Opening your windows and letting fresh air in for just 5 minutes a day can greatly reduce the humidity that is inside the room as well as allow fresh air inside.  If it’s cold outside, you can simply close the bedroom door and open the window so you won’t affect the rest of the home’s temperature. And all you need is just 5 minutes to bring that cooler, fresh air inside to help dry out the inside air.  Some people even use this practice to improve their indoor air quality throughout the day.

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