How to calculate your operating cost for blowing with compressed air - in 3 easy steps

 
1. Begin by finding out how much energy the compressor uses during an hour and how much compressed air is produced during the same time. Use a flowmeter to find out the amount of produced compressed air. It is important that you find out how many cubic feet that are produced per hour.

Convert cubic feet per minute to cubic feet per hour:
Amount of produced compressed air per minute * 60 minutes = Amount of cubic feet per hour. 


2. Now you have the knowledge about how many kilowatts the compressor uses per hour and how many cubic feet compressed air that is produced each hour. To be able to calculate the cost of one cubic feet of compressed air you need to know how many kWh it takes to produce one cubic feet compressed air.

Number of kWh / number of cubic feet produced during that hour= 
number of kWh it takes to produce one cubic feet compressed air.


3. In the last step you need to know the cost of electricity per kWh.

Number of kWh / cubic feet compressed air * cost per kWh = the cost per produced cubic feet of compressed air.
 
Compressed air cost - calculation example

The compressor uses 37 kWh and produces 196.7 cubic feet compressed air per minute.

196.7 cfm * 60 minutes = 11,802 cubic feet per hour.

The compressor uses 37 kWh and produces 11,802 cf/h.

37 kWh / 11,802 cf/h = 0.0031 kWh/cf
To produce one cubic feet it takes 0.0031 kWh. 

The electricity cost per kWh is $0.0726.
0.0031 kWh/cf * $0.0726 = $0.000225 /cf

This is equal to $0.000225 * 1000 cf = $0.225 per 1000 cf.

 

…but the cost does not just depend on the electricity price.

To make a truthful overview of the cost both maintenance, installation and other costs should be included. In the compressor industry it is common to say that the electricity costs stand for about 70% of the total cost during a ten-year period. To finish the calculation, the final cost should be divided by 70% to get the total cost including other costs.

$0.225 per 1000 cf / 0.7 = $0.32

The total cost of compressed air is therefore $0.32 USD per 1000 cf.

 

How do I minimize the use of compressed air?

It is first when you have calculated the total amount of used compressed air during a month or a year you actually understand the actual cost. Therefor it can be good to measure how much compressed air is used and investigate the saving possibilities. There are a lot of easy adjustments that will have large impact on the bottom line. It is not just economic benefits for the company but also a good way to become more climate friendly.