Interior Window Condensation

Just like condensation forms on a glass of iced tea on a warm summer day condensation can also form on your windows. This post will try to explain condensation on the interior of your home. When the temperature of the glass is cooler than the dew point condensation forms. Energy efficient windows can help but given the right conditions condensation will still form. Since it seeks out the coolest part of your house it may no longer be your windows. Closets and walls behind large pieces of furniture are areas to monitor on a regular basis.

How do I prevent condensation? Keep in mind that two sleeping adults exhale one liter of water in an eight hour period. Cooking and bathing habits also contribute to excess water vapor. Is your clothes dryer venting properly? Promote air circulation. Since water condensates on the coolest surface open your blinds during the day to allow surfaces to dry out. Crack the windows a bit to promote exchange of air. Leave the bedroom doors open during the day. Turn on exhaust fans or switch them out to a higher capacity model.

One idea that I thought was good came from a property management firm that I have dealt with in the past.  They were having problems with mold growing on the bathroom windows because the fan wasn’t being turned on when their tenants were taking a shower.   They remedied the situation by installing a motion switch on the fan so whenever someone entered the bathroom.   The switch had a delay on it so it would turn the fan off after a set time.

I have included a link to a publication produced by the National Fenestration Rating Council that also trys to explain condensation.

NFRC Condensation Information