You’re probably shopping for an air compressor because you’ve heard about the power of air tools over electric tools. If it’s not more torque and higher RPMs you’re looking for then maybe it’s the easy interchange between tools – almost as simple as plugging the tool into an outlet. Either way you’re convinced that you need an air compressor but you’re not quite sure where to start. This article will give you some of the basics about air compressors and then guide you through to selection by asking you five questions.

Here are some of the key attributes you’ll be paying attention to when you start shopping for your air compressor:

Air compressors, as their name implies, compress air. This takes an engine and engines have horsepower. The horsepower of the engine you’re considering has direct impact on all the other aspects of your compressor’s performance. Horsepower is often inflated, and you should be paying closer attention to the engine’s rated amperage for an idea of how powerful it is.

PSI stands for pounds for square inch. Of course as you remember from high school physics class PSI is a measurement of pressure. To be exact, how many pounds of pressure is applied per square inch. The PSI rating is one of the crucial ratings in the air compressor to understand as air tools have a minimum amount of PSI required to run. Typically that’s 90 PSI, but it depends from tool to tool.

CFM stands for Cubic Feet Per Minute and it’s a unit for measuring the rate of flow in or out of a space. In this case, the rate of flow of air out of your air compressor. Air tools typically require 4-6 CFM for proper operation.

Tank Size:
The tank size, measured in US gallons, tell you how much air is compressed and give you something of an idea of how long you can operate your air tool for at a time. The other factors that affect how long you can run your tool for are the PSI and HP of the engine itself as these factors determine how quickly your compressed air supply is replenished.

Now that you’ve got the very basics of Air Compressors, here are four questions that will help you make your decision

1) Who’s Using the Air Compressor, and What For?
Is it you in your shop on weekends building birdhouses? Or is it for your construction company’s framing up new houses? The level of use should be your first consideration when making a purchase and will help you determine how much of an investment really makes sense for your compressor. The aspects of the compressor you should be paying the most attention to here are PSI and horsepower. The higher these are the more power and continuous usage you’ll get out of your compressor.

2) What Air Tools Do You Plan To Use?
Will you be using an impact wrench in an assembly line automotive project? Or are you using a brad nailer to finish up your wood shop projects? Again, the amount of usage you’re applying to your tool is a key factor in determining the HP, PSI and CFM of your air compressor. Typically, for the wood shop owner, you’re looking at using finish nailers, brad nailers and narrow-crown staplers for your projects.

3) Will You Be Using More than One Tool At A Time?
If you’re running two tools at once from a single compressor then you will need to invest in a compressor with more HP, PSI and CFM. A larger tank size would be beneficial as well.

4) Will You Be Mobile or Stationary?
If you’re stationary then you’ll be fine with an electric powered air compressor. If not then you’ll need a gas powered compressor that you can bring with you to your electricity-free work site.

Armed with the basics of compressor lingo – PSI, CFM, Tank Size and Horsepower you should be a formidable consumer when you go shopping for your next compressor. Be highly skeptical when talking with compressor salesmen as they often know very little about the units they sell and seek to razzle dazzle you with big talk that won’t help you get the right compressor for your needs.

As always when choosing a new tool, know precisely how you plan to use it when making the purchase. Keeping this in mind will always lead you to the right tool for the job.

More Air Compressor Resources!
Air Compressor Terminology and Definitions
Finding the Right Air Compressor for Your Shop
The Basics for Choosing the Right Air Compressor
Supercharge your Air Compressor for 20 bucks or less (look at second post there)