The highest cost associated with air compressor ownership, is not the cost of the compressor, nor the cost of preventative maintenance, but the electrical cost associated with running the compressor itself. With the electrical cost being the most expensive portion of compressor ownership, can you really afford to run a compressor unnecessarily?
The standard billing is measured in kWh (Kilowatts per hour). Electrical rates vary greatly depending on time of day, location, and total usage, but for our example we’ll use a rate of 16 cents per Kilowatt-hour.
In this example we’ll use a 5 hp compressor. To convert horsepower to kilowatt, multiply the horsepower rating by .74. So, 5 horsepower x .74 gives us 3.7 kW.
We’ll use a conservative rating of 50%. During an 8 hour shift, we’ll assume that the air compressor is running for 4 hours. If we work with a single shift operation, and based our example on 5 days a week, 52 weeks a year, we come up with 4 hours a day x 5 days a week x 52 weeks per year = 1040 run hours per year.
Doesn’t sound like much, but keep in mind, we are talking a small compressor, in a small shop, with a relatively low run time.
At just about any shop you walkthrough, you can hear air leaks.
People think these leaks aren’t anything to be concerned with; that they are so small, they won’t matter. I think it’s fair to say, that an average shop would have the equivalent of a 1/16” holes worth of air leaks – from hose quick disconnects, leaking fittings, leaking tools, leaking drains, or a host of other sources. Think about it this way; a 1/16” of an inch is about the size of the tip of a pen and at 125psi of pressure, there is waste of 7.9 CFM worth of air. So, how much is 7.9 CFM? Well, remember that 5hp compressor we started our example with? Well, this compressor delivers an average of 17.5 CFM, so there is 45% waste of the total capacity.
The amount of air that’s wasted is exponential when compared to the diameter of the hole. At 1/16th of an inch, at 150psi, the leak rate is 9.1CFM, at 1/8th of an inch, that number more than triples to 37.3CFM!
At Air Compressor Works, we work on compressors from ½ a horsepower up to 300hp and larger. Our staff of highly trained service technicians and salesmen are constantly looking out for ways to make your compressed air system more efficient.