Fan Power Calculator
Brake horsepower and running cost of a fan.
Enter your values
ⓘ Live results
Results
- Brake horsepower
- 0.484 hp
- Input power
- 0.401 kW
- Annual energy
- 1,203 kWh
- Annual cost
- $192.53
- Watts per CFM
- 0.201
Quick answer
Fan brake horsepower equals CFM times static pressure divided by 6356 times the fan efficiency.
BHP = CFM x SP / (6356 x efficiency)
How to use the Fan Power Calculator
- 1Enter airflow and the static pressure the fan works against.
- 2Use the fan's efficiency from its curve, typically 55–70%.
- 3Add run hours and your electricity rate to see the annual cost.
Worked example
Using the values the calculator loads with:
Inputs
- Airflow2000 CFM
- Static pressure1.0 in w.c.
- Fan efficiency65 %
- Run hours per year3000 h
- Electricity rate0.16 $/kWh
Results
- Brake horsepower0.484 hp
- Input power0.401 kW
- Annual energy1,203 kWh
- Annual cost$192.53
- Watts per CFM0.201
Frequently asked questions
What is a good watts per CFM?
Efficient residential ventilation runs under 0.4 W/CFM; poor systems exceed 1.0.
Why include motor efficiency?
Brake horsepower is shaft power; the motor draws more from the wall, typically 10–15% extra.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.