A large bathroom with a jetted tub a toilet and a shower a common configuration in new homes would need a 200 cfm ventilation fan such as the broan l200 ventilation fan available from.
Cfm of bathroom fan.
The cfm rating measures the volume of air the fan moves.
Learning how to calculate cfm for a bathroom fan will help you purchase the right size fan for your space.
If you want need.
Make sure the fan you choose is powerful enough to ventilate your bathroom.
Bathroom vent fans are rated for the amount of air they can move measured in cubic feet per minute or cfm.
To be effective a bathroom fan needs to be powerful enough to completely replace the air in the room about 8 times every hour.
A bathroom exhaust fan that is rated 50 cfm is ok to use in bathrooms that are 50 square feet or smaller.
Bathroom vent fans serve an important function by removing humid air from your home to prevent mold and mildew from forming.
So if you have a bathroom that is 12 feet long 15 feet wide and 10 feet tall then it has a volume of 1800 cubic feet 12 x 15 x 10 and a cfm of 240.
A fan that s too small won t remove moisture and odors efficiently and will need to run longer increasing wear on the motor.
The effectiveness of the fan will be rated in cfm or cubic feet per minute of air moved.
Vent fans are rated by the number of cubic feet of air they move per minute cfm and it s important to buy a large enough fan for the size of your bathroom.
The rule of thumb is that you need at least 1 cfm per square foot of room area.
The cfm number should be equal to or higher than the listed square footage of the bathroom an exhaust fan is being installed in i e.
Use the room size to determine the necessary cubic feet per minute cfm rating of the fan.
Standard fan sizing.
The cfm represents the airflow required to completely exchange the air in your bathroom 8 times in one hour.
To meet energy star minimum standards a bathroom fan must have an efficacy level of at least 1 4 for small fans up to 89 cfm and a level of at least 2 8 for larger fans 90 to 500 cfm.
The result is the cfm or cubic feet per minute rating required for your bathroom fan.
The exhaust fan is designed to manage airflow in bathrooms as large as 85 sq.