When buying a ventilation fan for your bathroom, it’s important to make sure it moves enough air for the size of the room.
The airflow rate for bathroom ventilation fans is expressed as the number of cubic feet per minute (CFM) of air moved. The higher the number, the more air the fan will remove from your bathroom.
To calculate the size fan needed for a bathroom with a standard 8’ high ceiling, multiply the length times the width of the room. This number represents the minimum CFM rating needed for the vent fan.
For example, for an 8′ wide by 10′ long bathroom, you would need a ventilation fan rated for 80 CFM (8×10 = 80) or higher.
VIDEO TRANSCRIPT
Choosing the right ventilation fan for your bathroom includes sizing it properly. Airflow, or power in fans, is measured in cubic feet of air exhausted per minute or CFM.
For bathrooms with standard ceiling heights, first determine the number of square feet in the room by multiplying the length and width of the floor area. This figure is roughly what your new fan’s minimum CFM rating should be.
Generally speaking, more is better when it comes to bathroom ventilation, so round up, especially if you have taller ceiling heights.
Further Information
- How to Size a Bathroom Vent Fan (article)
- Bathroom Vent Fan Calculator (article)
- How to Properly Size a Bathroom Vent Fan (video)
- How to Replace a Bathroom Exhaust Fan (video)
