Minimize window condensation

Healthy HouseTM CleanAir Tip


Condensation can form on windows when enough temperature variation exists between the indoor air and the surface of the glass. Anytime this happens, it is a risk for mold growth.

Condensation occurs when the air temperature at the surface of the glass falls below the dew point. The dew point is the temperature air needs to cool to cause the water vapor already in the air to condense out as dew on surfaces. Dew point is a function of ambient air temperature and relative humidity. As air becomes more humid, condensate forms at even warmer temperatures.

There are a few simple things you can do to help minimize condensation on windows and prevent mold growth.

1. Single pane windows should be upgraded to a double-pane or triple-pane window. This will help eliminate temperature variation and keep the interior glass surface closer to the indoor temperature.

2. Humidity should be managed through ventilation or dehumidification and should not exceed 60% relative humidity.

3. Maximize the space between your window coverings and the window pane to promote air flow and evaporation. Fabric curtains should be replaced with less-porous window coverings or should be mounted with considerable distance from the window.

4. Sills, ledges and window encasements should be kept dust free to further prevent mold growth.