Buying an air compressor can be straightforward or complex. This page addresses the issue of how to buy the best compressor for a small shop, a question was asked of us recently.
We have covered this issue of acquiring a new compressor in a number of different ways. Getting the best compressor for a small shop means following all the same steps.
What is the compressor for?
Obviously, to provide compressed air. But what – exactly – are you using the compressed air for? Be exact. Think it through. Consider all the areas in which you will use compressed air in your shop now, and think about what you may use compressed air for in the future.
If it is a woodworking shop, for example, and you simply want compressed air for a blow gun to rid the woodworking equipment of wood chips, virtually any compressors with a few gallon tank size will do that.
A blow gun, one of which is shown in the image above, is typically used in short spurts of air, and even a small, fractional horsepower air compressor, should be able to provide enough air for that.
Is the air compressor going to be used for spray painting using a compressed air driven paint sprayer – one of which is shown below, or used for powering a grinder, or for using air driven tools to assemble things on an ongoing basis?
If that is the case, a small air compressor will not do.
How much air?
Many air-using devices are fed with compressed air at 90 PSI. Most compressors are able to provide compressed air at 100+ PSI, some even up to the 150 PSI range.
Therefore, if your air tool uses compressed air at 90 PSI, any air compressor can deliver air at that pressure.
The issue is… how much air will the air compressor deliver at 90 PSI?
And that’s where the rule of thumb about air compressors comes into it. As a rule to guide you in buying the best compressor for a small shop, the rule is that most compressors will deliver about 3-4 CFM of compressed air at 90 PSI for each HP of electric motor size.
For example, an air compressor with a 3 HP motor will deliver 9-12 cubic feet per minute of air at 90 PSI.
In order to apply that information to your small shop. you absolutely MUST determine what the flow demands of the air tools you wish to use are.
If, for example, the die grinder you want to use has an air demand of 20 CFM at 90 PSI, using the rule of thumb, you will need an air compressor with an electric motor of at least 5 HP in size to ensure that you are getting the flow needed to run that grinder.
You also want to have that 5 HP compressor on a 30 gallon tank minimum to give you reasonable work time with your die grinder before the compressor has to kick in to rebuild the tank pressure.
If you simply buy an air compressor because the price is right, and you do not take into consideration the air demands of the air tools you expect to be using – now and in the future – odds are pretty good that you will get an air compressor that is ultimately too small in air production to give you the air tool use you want.
Eventually then, you will be back buying a larger air compressor. Don’t make that mistake. Do a bit of homework first.
The Best Compressor For A Small Shop
The best compressor for a small shop then is one that…
- is the correct voltage (120 AC or 240 DC) to suit your shop power supply
- can deliver the amount of air your air tools require both in pressure and flow rate
- fits your budget
- one that you know where it can be fixed promptly if that is an issue for you, as air compressors will fail – sooner if you use them a lot – and when that happens, how do you get back up and running again?