How to Repair Window Condensation

Updated February 21, 2017

Temporary condensation commonly appears on windows during bathing, cooking, dishwashing, and laundering. However, condensation can become a problem if it remains on windows throughout the day or begins running down the walls, causing the growth of mould or mildew. If this is happening around your windows, you should take steps to repair window condensation before it can damage your home and create mould and mildew that can lead to health problems, particularly respiratory problems.

Install double- or triple-glaze windows. When purchasing double or triple-glaze windows, look for the Condensation Resistance, or CR, rating. The CR rating is determined by the National Fenestration Rating Council, or NFRC, and ranges from 0 to 100. The higher the number, the better the condensation resistance.

Seal any cracks around the windows. Cracks allow cold air to pass through, resulting in condensation. Use caulk or weatherstripping to seal the cracks around your windows.

Decrease the humidity in the air. By decreasing the humidity inside your home, you can prevent condensation from appearing on your window. Running a dehumidifier or an air conditioner is a good way to decrease humidity in the air. Ideally, the relative humidity in your home should be under 50 per cent. Many dehumidifiers come with a device that can measure relative humidity.

Increase ventilation. Opening windows for a few minutes each day, particularly after steam-producing activities such as cooking, can significantly reduce condensation.

Open drapes at night if condensation is occurring behind drapes. Keep in mind, however, that this can result in energy losses.

Things You'll Need

  • Double or triple-glaze windows
  • Weatherstripping or caulk
  • Dehumidifier or air conditioner
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About the Author

Thomas King is a graduate of the University of Pittsburgh School of Law where he served as managing editor of the "Pittsburgh Journal of Environmental and Public Health Law." He currently lives in Aberdeen, Washington where he writes and practices law.