Need help in the summer time when it is hot my bathroon ceiling and walls sweat or some sort of condensation ,the bath room shower is not being used ,there is a fan in the ceiling but it does not fit tight against the s ceiling could I be getting hot air from the attic hitting the cool air condition air in the bath room be causing this if so how do I fix the problem. The ceiling fan is not vent to the outside ,so I do this . Thanks mooney2

You could be right about warm, moist air leaking in. I am surprised it would be enough to condense on the walls. Do you live someplace very warm and humid in the summer time? I would start by removing the fan and trying to see why it doesn't fit better, adding caulking or even the foam sealing strips you press in. You might also try a flapper over the vent like on dryer vents to keep air from coming in the vent.

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Central Illinois thanks labman