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Does this image resemble any of your home windows? Window condensation is a common problem, but it has nothing to do with your window not performing properly. It’s actually the result of interior and exterior air temperatures. However, condensation can cause significant damage to your windows if not taken care of as soon as possible.

What Is Condensation?

Condensation is a film of moisture that forms from humidity. Humidity is created from water vapor that exists in the air around us. When it comes in contact with a cool surface, it creates droplets of water called condensation. You’ve probably seen this happen to your bathroom mirror after taking a hot shower.

Glass generally has a lower temperature than other surfaces inside the home, so condensation shows up more on them. With windows, condensation can form on the inside or outside. In either case, when you see window condensation, it’s a sign of too much moisture in the air.

What Causes Window Condensation?

There are two types of window condensation: interior and exterior. Interior condensation is caused by too much humidity in the home. It has nowhere to go, so it lands on various surfaces in the home, like walls, ceilings and windows. Being glass windows, condensation shows up more on them.

Exterior condensation happens when the dew point in the air (which measures relative humidity as a water-to-air-saturation temperature) is higher than the temperature of the exterior glass on your window. Exterior window condensation often occurs when a cool night is followed by a warm day. If you have low-emissivity or Low-E glass, seeing exterior condensation is actually a sign the window’s insulating coated glass is working properly.

How to Reduce Window Condensation

Although mild window condensation now and then is normal and won’t cause any major problems, excessive and repetitive condensation on windows is a cause for concern. It means the humidity in your home is way too high. We recommend following these measures to reduce window condensation.

  • Use vent fans in your kitchen, bathrooms and laundry room. The fans should vent to the outside of your home, not your attic.
  • Turn off any humidifying devices, including furnace humidifiers, and run a dehumidifier instead.
  • Open fireplace dampers to give moist air another avenue to escape.
  • Vent clothes dryers, gas burners and other appliances that use heat to the outdoors.
  • Open windows and doors for a few minutes every day to air out your home.
  • Check that ventilation in the basement, attic and crawl spaces is open and of the proper size for the space.
  • Open your window treatments to let air flow to the window.
  • Consider investing in an air-to-air exchange system.

How Condensation Can Damage Your Windows

Condensation that sits long-term on the interior of your window can damage the window and penetrate the surrounding wood, requiring a full window replacement. It can also promote mold and mildew growth and, in more extreme cases, collect in the walls and ceilings of your home and cause wood rot, floor buckling and structural damage.

If the above steps to reduce condensation on windows don’t work, you may need to update your windows. Newer windows have better and more venting options built-in and feature the latest technologies that improve their performance. For example, highly efficient windows, such as those with three or more layers of insulation, very rarely have condensation problems.

You can learn more about the different types of windows the Roofing Annex installs, as well as their condensation-reducing venting properties. If you want to update your windows or replace windows damaged by condensation, call or email the Roofing Annex. We’ll evaluate the situation and present you with options that complement the style of your home and meet your budget.

We know you’ll be happy with our replacement window prices, but you’ll love your new, condensation-free window view even better!