Fan Performance Laws

vol15n4.jpg
Date: 
2003
Volume: 
15
Number: 
4
Tip Category: 
Exhaust fans

There are very specific “laws” that dictate the relationship between fan speed, air moving capacity, and energy usage for any fan. For instance, fan speed and air moving capacity are proportional. That is, if fan speed is increased 10%, the air moving capacity of the fan will increase roughly 10%. Conversely, if fan speed is decreased 10% , the output of the fan will decrease roughly 10%. A second fan law states that fan power is proportional to the cube of fan speed. As a result, small changes in fan speed can have a dramatic effect on the power used by the fan.