Bath and Ventilation Fans Information

Bath and ventilation fanBath and ventilation fans initiate an exhaust airstream from structure interiors. This is done to remove humidity and stagnant air masses, and to draw fresh air from outside and adjacent rooms.




Bath and ventilation fans are employed in areas with reduced airflow, but a need for fresh air exchange is recognized. A large number of these fans remove humidity from bathrooms, as this represents a confined location that develops conditions that enable:

  • mold
  • fungi
  • bacteria growth

Many other residential and commercial locations, such as laundry rooms, basements, and workspaces also benefit from this type of ventilation.




Airflow created by bath and ventilation fans is rated as cubic feet per minute (CFM). Simple guidelines are one CFM per single square foot of floor space; bathrooms over 100 ft.2 should add 50 CFM for each water fixture. Noise level is another important selection parameter. Certain types are better suited for vertical or horizontal ductwork, and a limited few are ductless.


These simplified exhaust fans are typically round or square-shaped, no larger than 12 inches wide, and are controlled by a wall switch. Most of these devices also incorporate a light, some of which may utilize an incandescent heat lamp. Others utilize a downward blower to draw in outside air and may be coupled with a heat lamp. A night light option provides guiding illumination in darkness. Modern fans may feature motion sensing or humidity sensing to automate some functions.


Related Information

CR4 Community—Battery Powered Bathroom Fan

Electronics360—A House Fan Equipped with Machine-Learning Tech? Why Not?

Image credit:

Tha-uzhavan / CC BY-SA 3.0




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