How to Choose an Air Compressor in 5 Questions

questions to ask when choosing an air compressor

Although the number of air compressor choices can be overwhelming, selecting the right one can be made easy by asking a few important questions.

What is the application?

Air compressors are used for a wide range of jobs — from inflating tires to powering tools to operating a factory. The application will determine the type of compressor you need. For example:

  • Portable air compressors are well-suited for one person operating air tools
  • Stationary, single-stage air compressors are often used for wood shops, automotive restoration and maintenance, small businesses, or facility maintenance.
  • Two-stage air compressors are recommended for multi-bay automotive shops, light commercial shops and industrial applications.
  • Rotary screw air compressors are recommended for applications that need constant volumes of air, which would require a compressor to run 100 percent of the time to keep up with the tools necessary for the job.

What air tools will you be using?

Some air tools require more air than others. This is measured by standard cubic feet per minute (scfm). There are several steps you can take to select the appropriate air compressor based upon your tools.

First, find the tool that requires the greatest amount of scfm and multiply that number by 1.5. This will give the compressor some room for future expansion or heavier tool use. If operating more than one tool at a time, add together the scfm requirements for each tool then multiply that number by 1.5.

Next, make sure the compressor chosen offers cubic feet per minute (cfm) output equal to or greater than the requirement of the equation in step one. For example, if the tools you plan to use individually are an impact wrench with a 5 scfm rating, a ratchet with a 4 scfm rating, and a dual action sander with a 9 scfm rating, then the air compressor must have a cfm rating of 13.5 or more. This is because the dual action sander has the highest scfm requirement, and 9 scfm multiplied by 1.5 is 13.5 cfm.

If you plan to use all three of those tools at the same time, the compressor must have a cfm rating of 27 or more — a rating reached by adding together the scfm requirements of the three tools (18) and multiplying that number by 1.5.

How often will you use the air compressor?

If you plan on regular use — several times a week — then select a compressor with a 50/50 duty cycle, such as a portable cast iron or contractor compressor.

For daily commercial or industrial use, select an air compressor with a higher duty cycle, such as high performance cast iron, single stage, two stage, or rotary screw compressors.

Be aware that air tools requiring larger air consumption will require a larger air compressor to operate appropriately. This should be taken into consideration above all else.

What type of power is available?

Portable compressors typically operate on 115-volt, 15-amp circuits. Stationary, single-stage compressors and some large portable compressors operate on 230-volt, single-phase power. Two-stage air compressors that are 10 hp and larger operate on three-phase power only, while 5 hp and 7.5 hp two-stage compressors are available for single-phase and three-phase power. If no electrical power is available, a gas air compressor is required.

Do you have plans for future expansion?

If there are plans to expand the business or operation in the near future, and these plans will require more air, it’s less expensive to buy up to the next larger air compressor now than to purchase a second compressor in the future.

Use these tips to explore our wide variety of air compressor options to find one that’s right for you.