Bathroom vent fans are rated for the amount of air they can move, measured in cubic feet per minute, or cfm.
37+ Bathroom Fan Cfm Per Square Foot
Images. The fan pulls air out of the bathroom and allows fresh air to be drawn in; The result is the cfm, or cubic feet per minute rating required for your bathroom fan.
Broan-Nutone Attic Ventilator - 1050 CFM Black Dome ... from i.pinimg.com
Derives the ventilation rate from the volume of the space (in cubic feet) to be ventilated multiplied by the number of total air changes in one hour. For bathrooms that are larger, you need to select a fan that can move at least 1 cfm. This will provide approximately 8 air changes per hour.
Fans should be installed as close to the shower as possible and, if marked as suitable for this.
As we've already said, you need 1 cfm per square foot. For example, a 7′ x 10′ bathroom would require a 70 cfm fan. Cfm stands for cubic feet per minute (it is also referred to as airflow). The standard rule for bathrooms 100 square feet or smaller is one cfm per square foot of the bathroom.
