How to Size an Air Compressor Accurately

Wondering, “What is an accurate size air compressor for my project?” Depending on the work you do, the air compressor you use can be a big, bulky machine. Not only are they expensive to buy in the first place, but they also can cost a lot to run.

Choosing the right air compressor can save you money in both the short- and long-term. If you buy too small, you’ll run it to death; but if you buy too big, you risk paying too much to run it.

If you’re asking yourself, “What size air compressor do I need?” read on to learn how to size an air compressor the right way.

Determine how much air you need

Start your search by determining how much air you need to complete the jobs you do on a daily basis. Take inventory of your shop or factory, and take a close look at all the tools that require air. Check their individual cubic feet per minute (CFM) demand. Determine which tools, if any, you’ll use at the same time and how much CFM they’ll need collectively.

Once you’ve settled on an estimate, add about 30 percent to the total CFM number. That way, you’ll have a buffer to account for any air leaks or peak air requirements.

Determine how much pressure you need

All the tools you use require certain levels of pressure, known as pounds per square inch gauge (PSIG). Take a look at each of your tools since they each may require a different PSIG. The maximum pressure you need to power your tools will help you determine which compressor is the best match for the PSIG.

Gauge how often you’ll use the machine

An important part of determining what size air compressor you need is gauging its duty cycle. This is a measurement of how often you’ll use the machine. Measuring a duty cycle helps you determine how much air you need and how long you’ll need it, which then gives you an idea of what air compressor control system you’ll need.

Generally, there are five types of duty cycles:

  • 25-percent duty cycle: Run time is one-fourth of total cycle time. With this cycle, the compressor needs one minute and 30 seconds of rest after every 30 seconds of activity.
  • 30-percent duty cycle: Run time is one-third of total cycle time. Under this model, a compressor with a 60-second cycle time would have 20 seconds of run time followed by 40 seconds of rest.
  • 50-percent duty cycle: Run time is half of total cycle time. For a two-minute cycle, you’ll have one period of pressurized activity followed by one minute of rest.
  • 75-percent duty cycle: Run time is three-fourths of total cycle time. For a one-minute cycle, pressurization occurs for 45 seconds followed by 15 seconds of rest.
  • 100-percent duty cycle: The compressor delivers pressurized air for minutes or hours on end. A 100-percent duty cycle is ideal for processes that require constant airflow, like painting or sanding.

Need help determining the accurate size air compressor you need for your project? Wenniger Compressor Co. is happy to help. With nearly 90 years in the industry, we can quickly and easily help you choose the best compressor for your daily applications.

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