Under certain conditions, window condensation can occur both inside and outside your home, but your windows are not the cause of the condensation. Condensation, or “sweating” on windows, is caused by humidity (or water vapor), which is present in virtually all air. When the water vapor comes in contact with a surface the vapor condenses. This often happens to bathroom mirrors and walls after someone has taken a hot shower. Condensation can also occur on windows during the winter if the humidity inside your home is too high.
Even windows on the same wall can have varying levels of condensation. This happens due to varying humidity levels, elevation, landscaping near windows and different levels of exposure to the sun.
Many everyday activities produce water vapor, which will cause condensation. A five-minute shower releases a ½ pint of water vapor, cooking dinner on a gas stove can produce 2½ pints of water vapor and the breathing of a family of four can produce approximately ½ pint per hour.
Although it can be an uphill battle, there are a few things you can do to help control moisture levels in your home.