Use the free Air Flow Calculator on ToolVexa to estimate the air flow needed for a room in cubic feet per minute (CFM) from its size and air changes per hour.
How to Use
Enter the room length, width and ceiling height in feet, and the air changes per hour, then press Calculate.
Formula in Plain Words
Room volume is length times width times height. Air flow in CFM is volume times air changes per hour divided by 60.
Worked Example
For a 20 ft by 15 ft room with an 8 ft ceiling and 6 air changes per hour, the volume is 2,400 cubic feet and the air flow is 240 CFM.
FAQs
What air changes value should I use?
It depends on the room type. Living rooms often use lower values and kitchens or bathrooms higher ones.
Is this a ventilation design tool?
No. It is a simple estimate, not a substitute for professional ventilation design.
Does it allow for duct losses?
No. Duct and filter losses are not included.