If you are indoors, use the CFM of the desired fan and the volume of the space to determine the amount of fans. (Keep in mind they need an air inlet and outlet for air flow.)

Use this formula:

  • Fans Needed=Volume/(Fan Volume x Transfer Time)

Calculate volume:

  • Example: Factory 50ft x 80ft x 15ft = 60,000 cubic feet

Choose a fan (See Chart Below):

  • Example: Choose 30” fan. CFM = 10000

Choose time to transfer the total volume of air for the space being cooled.

  • Example: Every 2 minutes (I recommend time between 1-3 minutes.)

Determine fans needed:

  • Example: 60000/(10000 x 2 mins) = 3 fans

Fan Chart

PN Size Description CFM
F10-01-004 20" 20" Cage Fan, Single Speed 5500
F10-01-005 24" 24" Cage Fan, Single Speed 8000
F10-01-008 24" Multi-Speed, Oscillating 6800/1100
F10-01-008 24" Multi-Speed, Non-Oscillating 6800/1100

If you are outdoors, the wind affects this calculation directly correlating with the transfer time. This makes it difficult to use this calculation.