During cold weather, my bathroom vent fan builds up condensation and is dripping/leaving water stains on the ceiling. I had not been using the fan, but even after letting it run, it still happens. The bathroom is not large (about 6x6 or so) and i do not believe the fan is under-powered. I tried putting insulation over the fan box in the attic to make the metal less cold and am waiting to see how that works. The fan vents through some flexible pipe in the attic and goes about 5 feet to the soffets.
Anybody out there have this type of problem? Any suggestions?