Winter Window Condensation

Around this time of year, many condominium owners, directors, and managers ask us: why are my windows dripping with water? Condensation is a common issue for older condominium windows and even some new windows. Here are some tips to better deal with condensation:

1. Open your blinds or curtains. Having them closed can reduce the temperature of your window frames and increase the potential for condensation. Opening your window coverings will allow warm interior air to reach them, raising your window frame temperature and drying the condensation.
2. Use your fans. The relative humidity in your unit may be too high for your windows. Using bathroom and kitchen fans more often can bring in fresh dry air and reduce the potential for window condensation.
3. Lower your humidifier settings. Most windows can only tolerate about 20% relative humidity when we reach cold January/February temperatures. Consider lowering relative humidity to 30% when temperatures drop below 0C, and 20% when temperatures drop below -10C.
4. Ensure your operable windows are fully closed. Leaving them slightly open can lower the window frame temperature enough to cause condensation.

If your problem still persists, feel free to reach out to your engineering consultant to ask for further tips on dealing with condensation. They should be able to provide you with standard tips and comment on the condensation performance of your window systems.

Every window system has a different condensation rating (i.e. ability to resist condensation) and new windows with higher ratings generally come at a cost premium. When it does come time to replace your windows, speak to your engineer about your expectations and your budget. New windows are a long-term investment and condensation resistance is not something to overlook when making your big decision.

Jordan Swail, BESc, P.Eng., BSS

Project Engineer
Building Science and Restoration

Read Jones Christoffersen Ltd.

rjc.ca