Enter the time, power rating, and number of fans into the calculator to determine the power consumption.

Exhaust Fan Formula

The following formula is used to calculate the power consumption of an exhaust fan.

PC = T * P * H

Variables:

  • PC is the power consumption (kWh)
  • T is the time the fan is running (hours)
  • P is the power rating of the fan (kW)
  • H is the number of fans

To calculate the power consumption of an exhaust fan, multiply the time the fan is running by the power rating of the fan, then multiply the result by the number of fans. This will give the total power consumption in kilowatt-hours.

What is an Exhaust Fan?

An exhaust fan is a ventilation device designed to extract stale, impure, or hot air from a room or enclosed space and replace it with fresh air from the outside. It is typically installed in areas such as bathrooms, kitchens, or industrial settings where there may be smoke, fumes, moisture, or unpleasant odors. The fan works by creating a pressure difference that allows the undesirable air to be forced out, improving the overall air quality and temperature regulation.

How to Calculate Exhaust Fan?

The following steps outline how to calculate the Power Consumption of an Exhaust Fan.


  1. First, determine the time the fan is running (T) in hours.
  2. Next, determine the power rating of the fan (P) in kilowatts.
  3. Next, determine the number of fans (H).
  4. Next, gather the formula from above = PC = T * P * H.
  5. Finally, calculate the Power Consumption (PC) of the Exhaust Fan.
  6. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

time the fan is running (T) = 5 hours

power rating of the fan (P) = 0.8 kW

number of fans (H) = 2