Turn room size and an air change rate into cubic feet per minute.
How it works
Room volume times air changes per hour, divided by 60, gives CFM.
Before you order
- Workshops and garages commonly use higher air changes than living spaces.
- Check a fan performance chart at real static pressure, since listed CFM often assumes none.
- Add a make-up air path or the fan will not move its rated air.
Common questions
What air change rate should I use?
It depends on use and local code, so use the rate your code or equipment maker specifies.
Is this for sizing a furnace?
No. This is a ventilation calculation. Heating and cooling airflow comes from the equipment and duct design.