Yes, bathroom fans need to be vented outside. If they are not, the fan will recirculate moist air and vapor back into the bathroom, which can lead to moisture damage and mold growth.

Yes, bathroom exhaust fans need to be vented outside. Bathroom exhaust fans remove moisture and pollutants from the air in your bathroom. If these pollutants are not exhausted to the outdoors, they can accumulate in your home and cause health problems.