Many people notice water droplets, fog or frost on the glass pane of a window or door. This moisture is water condensation. Window condensation is a problem in newer air tight, properly insulated homes. The condition is especially noticeable in the winter when warm water vapor in the air meets glass that has a cooler temperature. The vapor is then transformed into water.
There are a few situations which create an environment that causes condensation, but these conditions are only temporary. The first few weeks after the furnace is turned on condensation may be noticed. This is normal and is not long lasting. Also condensation is likely when the outdoor temperature drops dramatically. Individuals living in a recently remodeled or constructed home may notice condensation as the building materials contain certain levels of moisture, but this evaporates in about twelve months.
Bathing, cooking, doing laundry, fish tanks, houseplants and washing dishes are sources that release water vapor into the air. Unless there is ventilation or fans in these areas, chronic condensation damages the wood frame of the window. In some instances, it also damages the surrounding dry wall. Eventually mold and mildew adds to the dilemma. Bay and bowed windows are more susceptible because of their design, which prevents air circulation around the glass.
The first step in reducing window condensation is to minimize indoor humidity. Kitchens, bathrooms and laundry areas should be equipped with exhaust fans to be used when household activities supply moisture to the environment, or merely opening the windows in these areas briefly during cold months and longer during warm months, allows moist air an escape route. Humid air that is not expelled is eventually circulated throughout the house. Ceiling fans help to circulate and dry moisture-laden air.
Individuals can improve ventilation by adding or upgrading attic, roof or soffit vents. These vents must be open and unobstructed to function properly. A dehumidifier is especially helpful during the colder months when windows and doors are opened infrequently. Some suggest never allowing internal humidity to rise above 27%.
If windows are not covered, install blinds, curtains, drapes or shutters. These coverings hold heat around the window, raising the glass temperature and decreasing the likelihood of condensation forming. If condensation is noted on windows that have treatments, open them and allow warmer air to come in contact with the glass.
Circulating warm air toward windows with a fan also reduces the risk of condensation. Make sure areas around the windows and doors inside and out are properly sealed. If there is condensation forming between a double glass paned window, the seal is ineffective and the window may need to be replaced.
Ensure unnecessary moisture is not gaining access into the house by minimizing the number of house plants. Wood stored indoors for fireplaces and wood-burning stoves carries internal moisture. Cover these wood stacks with plastic when storing indoors. Check air conditioning systems to be sure they drain away from the foundation. Make sure there is adequate insulation in attics and crawlspaces and that water seepage is not a problem.
Homeowners who have tried numerous techniques to prevent condensation without success may consider other alternatives. The newer vinyl framed windows and double glazed windows are less likely to experience condensation due to an increase in insulation.