Need Advice Condensation from bathroom exhaust fans

Ever since I've had a whole house humidifier, each winter when the outdoor temperature dips into the 20s I get a significant amount of condensation dripping down from the bathroom vents onto the floor and also seeping into the surrounding ceilng and leaving water stains. The indoor humidity is set to 40, and even when I've tried turning it down to 30 I've still had the same problem. I replaced one of the fans which had stopped working this past fall, and I replaced the entire metal housing including the flapper, etc. (not just the motor), thinking the flapper may have become stuck open and letting in cold air, but this also didn't make any difference. I've looked up in the attic above one of the fans which was easily accessible and there seems to be plenty of insulation sitting on top of the fan box. However I did notice the ventilation pipes leading from the box to the roof do not have any insulation. Not sure if this could be the cause. Anyone else have this issue or any suggestions on what else to try?

 

Our vent pipes in the attic for the bathroom don't have any insulation.

My parents had a similar problem once, and it was traced back to a leak in the roof when the house was about 15 years old. Great house, custom built but I guess just one of those things.

We once got a very professional and quick estimate from roofers911.

Good luck, Mike

 

Same problem, too much condensation, especially in the cold months. The bathroom fan put in by the builders was WAAAAY underpowered (50 CFM) for the size of the bathroom. I installed a new unit (110CFM). Not only much quieter, but no ceiling condensation, not even steamy mirrors...