Air Flow (CFM) Calculator
CFM from Room Dimensions
CFM = (Room Volume × ACH) / 60
ACH from Known CFM
ACH = (CFM × 60) / Room Volume
Formula
CFM = (Length × Width × Height × ACH) / 60
Frequently Asked Questions
How do I calculate CFM for a room?
CFM = (Room Volume × ACH) / 60. First calculate the room volume (L × W × H in feet), multiply by the desired air changes per hour, then divide by 60 to convert to cubic feet per minute.
What are typical air changes per hour?
Bedrooms: 5-6 ACH, Living rooms: 6-8 ACH, Kitchens: 15-20 ACH, Bathrooms: 8-10 ACH, Garages: 6-8 ACH, Labs/workshops: 10-15 ACH.
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