How Big of an Air Compressor Does Your Auto Shop Need?
We get this question a lot, and there isn't a useful answer based only on the number of bays in the building.
A five-bay shop can have very little air demand. Another five-bay shop may have multiple technicians using air tools, two tire changers, blast equipment, pumps, and other pneumatic equipment at the same time.
The compressor needs to be sized around what the shop actually uses.
Start with CFM, not horsepower or tank size
When comparing compressors, CFM is one of the most important numbers.
CFM tells you how much air the compressor can actually deliver.
Horsepower can be useful information, but it doesn't tell the whole story. And a giant tank does not make an undersized compressor produce more air.
The tank stores air.
The compressor has to make it.
Look at everything using compressed air
Make a list.
That might include:
- Impact guns
- Air ratchets
- Tire changers
- Inflation equipment
- Hose reels
- Pneumatic pumps
- Blow guns
- Air-operated oil equipment
- Other shop equipment requiring compressed air
Then figure out which of those are likely to operate at the same time.
You don't necessarily need enough compressor to run every air tool in the building simultaneously at full demand. But you also don't want a compressor sized so closely to the minimum requirement that it spends its entire life trying to catch up.
Tire equipment can change the calculation
Don't forget the equipment in the tire area.
Modern tire changers can use a significant amount of air, particularly during bead seating and other high-demand operations. If you're installing multiple tire machines or replacing old equipment, include their requirements when sizing the compressor.
Think about tomorrow's shop too
If you're already close to the compressor's capacity and planning to add bays or equipment, don't size the replacement around what you're using today.
Nobody likes replacing a compressor and discovering two years later that they've already outgrown it.
Leave reasonable room for future demand.
Electrical service matters
Before getting too far into compressor selection, find out what electrical power is actually available at the installation location.
Larger compressors may require three-phase power or electrical upgrades. That can have a major impact on the total project.
It's better to figure that out before the compressor shows up.
Where is the compressor going?
Location matters.
The compressor needs adequate ventilation and enough room to service it. Noise may also determine whether you want it in the main shop, a mechanical room, or another suitable location.
And don't forget the piping.
You can buy a properly sized compressor and still have poor performance at the tool if the compressed-air distribution system is undersized, badly laid out, leaking, or full of restrictions.
Do you need an air dryer?
That depends on the application and the air quality you need.
Every compressed-air system has to deal with moisture. For many shops, proper filtration, moisture separation, and refrigerated drying can make a major difference, especially when air quality is important for equipment or painting.
The compressor is only one part of the system.
Don't size it from an internet chart alone
Charts are useful for getting into the ballpark.
But if you're spending thousands of dollars on a compressor that you expect to run for years, it makes sense to look at the actual shop.
We can review your equipment, expected demand, electrical service, available space, and future plans and recommend a compressor that makes sense for the application.
Northcoast Equipment Specialists provides compressed-air equipment sales, installation, and service throughout Northeast Ohio.
How to Properly Size an Air Compressor