Seems strange that there's enough moisture in the house to leave condensation on all windows. I typically run into problems in say bedroom and bathroom areas. I agree with DavidR that you need to track down the source of all of this moisture. If there are no ventless appliances in the home, could there be an issue with the furnace venting properly?

Is there a gas range with some crazy lady cooking all day long with no exhuast system?

Are there exhaust fans in the bathrooms, and are they used during and after showering?

Are there 3 families living in a small rental house designed for a single family? I see so many issues with rental houses that my first question would be "is this a rental"

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