I live in Orleans, Ontario and I have just purchased a home that was built in 1988. This week when the temperature has dropped below 0 (C), I am seeing a lot of condensation on the inside of all of the windows. There are small puddles of water accumulating on the sills. The windows are wood framed and I can't imagine the condensation being good for them. The bathrooms are vented, but I don't know where they vent to.
Answer:
You have too little ventilation in the house. Opening all the windows a sixteenth of an inch will not lose you any heat but it will take the condensation off the windows. Once its gone, you can start closing the windows one at a time on each level but I doubt that you'll ever get to the point where, during the heating season, you'll be able to close all of them completely. You must find out where the bathrooms are vented to because if its not to the outside, your problems can multiply.
