Water Dripping From Bathroom Fan. The bathrooms have excessive water vapor in the air. On a cold day the moisture in the air will condense on anything below the dew point.
The bathroom fan starts dripping when warm moist air condensates in an uninsulated or poorly insulated ventilation duct. What type of professional do I call. No matter how powerful a fan how well insulated the duct you are blowing warm MOIST air into cold air which makes that moisture in the air condense into water droplets.
Take the roof vent in this first picture.
Bath exhaust fans should not drip. Eventually the water drip back to the bathroom through the exhaust fan. My bathroom fan leaks water during very heavy rains. If bath fan ducting isnt properly insulated the moist air from your house will condense inside the duct.