# Fan Horsepower

on . Posted in Pump

Fan horsepower, abbreviated as $$FHP$$, is a measure of the power required to drive a fan.  It is used in the design and operation of various systems, particularly those that involve ventilation, air conditioning, and industrial processes where fans are used to move air or gases.  The fan horsepower is a reflection of the energy needed to overcome the resistance or load imposed by the system.

Understanding and accurately calculating fan horsepower is crucial for proper system design, energy efficiency considerations, and for selecting the right fan and motor for a given application.  Oversized or inefficient fans can lead to unnecessary energy consumption and increased operational costs.  On the other hand, an undersized fan may not provide sufficient airflow for the intended purpose.

### Fan Horsepower formula

$$FHP = ( 0.000157\;/\; \eta_p ) \; CFM \; SP$$

$$FHP = CFM \; PSF \;/\; 33000 \; \eta_f$$

$$FHP = CFM \; PIW \;/\; 6356 \; \eta_f$$

Symbol English Metric
$$FHP$$ = fan horsepower   $$lbf-ft\;/\;sec$$   $$J\;/\;s$$
$$CFM$$ = cubic feet per minute $$ft^3\;/\;min$$ $m^3$ \eta_f $(Greek symbol eta) = fan efficiency$ dimensionless  PIW $= inches of water gauge$ in  mm  PSF $= pounds per square foot$lbm\;/\;ft^2kg\;/\;m^2 \eta_p $(Greek symbol eta) = pump efficiency$ dimensionless  SP $= static pressure $$ft^3\;/\;min$$$m^3\;/\;min\$

Tags: Horsepower