Ductless bathroom fans remove odors and germs by filtering the air through an activated charcoal filter. These fans have a lower blade speed, also called a tip speed, which allows more air to be sucked up into the filter. Once cleaned, the air is re-circulated back into the bathroom.
Since no duct work is required, these fans may be installed on the ceiling or on a wall. Some fans are wired to run when the bathroom light is tuned on, while others have their own switch. A disadvantage to the fan/bathroom combination is that the fan sometimes isn't left on long enough to remove odors.
Ductless bathroom fans are quiet and energy efficient. Regular maintenance includes changing of the charcoal filter, cleaning of the air vents and the servicing and cleaning of the motor. Optional accessories include variable speed controls and rocker control switches for both the combination fan/bathroom and separate switch options.
Building codes should be checked before installing a ductless bathroom fan to make sure it's allowed in the type of home being remodeled and in its location. Homeowners doing their own installations should have a working knowledge of electrical wiring. If not, it's best to have the fan and switches professionally installed.