Condensation on Windows Can Signal Excess Humidity: How This Can Damage Your Home

When you have excess humidity in your home, one of the first places you may notice it is on the windows. Condensation on windows can take the form of water droplets, fog, frost or ice. This type of condensation is a reliable sign that there’s more moisture in your indoor air than needed to maintain indoor comfort. The following introduction to indoor humidity can help you understand its causes, what it can do to your home, and how you can fight it.

Relative Humidity

The air around you contains a certain amount of humidity at all times. Relative humidity is the amount of moisture the air contains relative to the amount of moisture it would take to saturate the air at the same temperature. Indoor relative humidity levels between 30 and 50 percent are usually sufficient to keep your living environment comfortable. When humidity levels rise higher than 50 percent, however, you can start to see the effects of excess humidity throughout your home.

Condensation on Windows

Condensation on windows is an early and reliable sign that humidity levels in your home are probably too high. It’s more likely to occur during periods of cold temperatures because of the differences in temperature between the inside and outside environment.

Condensation on windows occurs when warmer air from the center of the room, which holds more moisture, moves toward the walls or windows at the edge of the room. When this air contacts a cold window pane, it can no longer hold the moisture it contains and condensation forms.

Remember that it’s not the windows themselves that are causing the condensation to form. Windows, in this case, are just the most obvious location where condensation can be seen. Putting in new windows will not solve problems with condensation.

Other Signs of Excess Humidity

In addition to condensation on windows, there are other signs of excessive humidity in your home that you should watch out for. These include:

• Physical discomfort, including clammy skin that feels too moist
• Sticky floors or walls
• Stuffy indoor air that feels hard to breathe
• Moisture stains on walls, ceilings or floors
• Increased amounts of mold or mildew
• Musty, damp odors
• Condensation of water pipes
• Obvious signs of moisture damage to books, electronics or other belongings

Causes of Excess Humidity

• Poor indoor ventilation – Homes need to be properly ventilated to get rid of stale air and bring in a constant supply of fresh outdoor air. Buildings with tight, energy efficient seals may not have enough ventilation to keep the indoor moisture level under control. Homeowners may also be wary about adding ventilation systems that could lead to loss of conditioned air in the summer or winter.
• High outdoor humidity – High outdoor humidity levels can contribute to excess humidity inside your home. This is more likely to be a problem in the summer, but outdoor humidity will always have an effect on indoor humidity.
• Humidity-generating appliances – Certain types of appliances, such as washing machines, clothes washers and clothes dryers can increase indoor humidity levels
• Humidity-generating activities – Cooking, bathing, cleaning and other activities that generate steam or moisture can make your indoor environment more humid. Taking showers or heating water on the stove are two of the main sources of moisture in this category.
• Water leaks – If there are water leaks anywhere in your home, this constant flow of water could contribute to making your indoor spaces more humid. Even small leaks can create a substantial amount of water flow over time. The problem could be made even worse if the leak hasn’t been discovered yet.

How Excess Humidity Damages Your Home

Excess humidity in your home is water in the air — maybe not as severe as a flood or a leak, but it can still cause water damage to your home’s structure, your belongings and your important equipment. Here are some of the most common areas where high humidity can cause damage or other issues.

• Flooring and carpets – Excess humidity can contribute to the growth of mold and mildew in flooring or carpets. Once mildew gets established in carpets, it can be difficult to completely remove. It can lead to discoloration and unpleasant smells. High humidity could also cause hardwood flooring to warp or crack, causing expensive damage to the floor. In extreme cases, high humidity can cause rotting in the flooring and subflooring.
• Walls – On the walls, high humidity can cause wallpaper to peel or crack and paint to bubble, peel or crack. Inside the walls, excess moisture can get into insulation and reduce its effectiveness at keeping warm air inside your home and cold air outside. Insulation could also develop mold and mildew problems. Moisture inside the walls can also cause drywall to crack or develop stains.
• Stored belongings – Any items stored in your home could be affected by excess humidity. Again, mold and mildew on clothes, books, papers or similar items may be one of the most obvious results of high indoor humidity. Dry food could go stale if it pulls in moisture, and canned food may rust and leak. This could cause even further problems with rodents or insects. Electronics such as computers, stereo and audio equipment, and cell phones can be affected by high humidity.
• Basements and crawl spaces – Excess humidity in basements and crawl spaces can combine with moisture from groundwater to create an environment that’s also prone to mold and mildew growth. Moisture problems can cause dank, musty, unpleasant smells in your basement area. Any belongings or objects stored in the basement could be affected by high levels of moisture in the area.
• Attics – Attics, especially unfinished ones, can get extremely hot and humid in the summer. Though you probably won’t have much problem with condensation on windows in the warmer months, high levels of attic humidity can cause the same types of problems in this space as elsewhere, including mold and mildew, damage to the structure of the attic, and damage to any items stored in that area.

Stopping Condensation on Windows

There are two major ways of stopping condensation on windows in your home.

• Install double-pane windows – Double-pane windows, sometimes called insulated units, are made of two panes of glass separated by a spacer made of metal or other substance. They’re often filled with air or the inert gas argon that serves as an insulator. The double-pane construction means that the inner glass pane doesn’t make contact with the outdoor air, keeping it from getting cold and preventing condensation from forming.
• Use drapes or curtains – Pull drapes or curtains across the windows to reduce the amount of indoor air that reaches the window glass. This can help prevent the extremes in temperature that cause condensation to form.

Controlling Excess Humidity in the Home

Other methods for controlling excess humidity can also help cut down on window condensation while keeping indoor moisture at recommended levels.

• Use a whole-house dehumidifier – A whole-house dehumidifier is designed to be installed in conjunction with your heating and cooling system. The humidifier is arranged so that all the air that moves through the furnace, air conditioner or heat pump also travels through the dehumidifier.
  Inside the dehumidifier, moisture is removed from the air before it completes its track through the HVAC system and out into your home. The cycle continues as air picks up more moisture and is directed back through the dehumidifier.
• Use room dehumidifiers – Smaller humidifiers designed for use in single rooms can also be effective for removing humidity, but they won’t get rid of as much as a whole-house model. Concentrate the use of room-level dehumidifiers in areas where humidity levels are highest.
• Run ventilation fans – Your kitchen and bathroom are significant sources of indoor humidity. They both probably have ventilation fans that can be turned on to remove excess moisture caused by cooking, cleaning or bathing. Make sure you run the fans during these activities and for at least a few minutes afterward to remove additional moisture from the air.
• Clean up spills and repair leaks – If there’s been a spill or flood, make sure it’s cleaned up and the area is dried out as soon as possible. Use a carpet extractor to remove liquid from carpets and set up fans to speed drying. Remove wet rugs, furniture or other objects. Find and repair any water leaks in your home, giving special attention to hidden areas where a leak could go on for days or months without being noticed.
• Vent appliances outdoors – Make sure your clothes dryer and other moisture-producing appliances are vented to send moisture-laden air outside. Don’t vent these appliances to a point inside the home, such as the attic or basement.

For more information on condensation on windows and indoor air solutions that can prevent this phenomenon, talk to the pros at Griffith Energy Services, or give us a call at 888-474-3391.

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