Air compressor size, power and CFM are not that difficult to understand, but they do take a bit of research to fully grasp. It’s best to figure out your needs for these three aspects of the compressor before making a purchase. The first thing you will need to figure out is how much air you’re going to need and which tools you’ll use. These three factors come into play in reference to the air tank that is mounted on the compressor’s unit, the horsepower of the motor, and the pressure that is discharged for how much air is being delivered.
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Size of Air Compressors
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In terms of size, compressors have a number of various choices. The biggest tank size of course means you will have more air. However, bigger tanks are also costlier and harder to maintain. They take up more space, which is an issue if you are going to be keeping the air compressor in your in your home or garage. You can get a tank anywhere from one to eighty gallons, so you definitely want to think about the right size of tank for your needs.
To determine which size is best, simply figure out what kind of work you will be doing. if you’re powering a number of different air tools over a long period of time, you’ll have to get a bigger tank. When it runs out, you’re going to need to recover the air that has been used, which takes some time as well. Having a larger tank, a 80 gallon air compressor for example, means you will likely never run out of air if you just use a few tools at intermittent times. But if you are using the tank for your job, as an example, you’ll need to have plenty of air that can be run through constantly.
Consider what type of tools you will be powering, as well. Nailers and brad guns just power through smaller bursts of air and don’t use that much air from the total tank allotment, so the compressor can quickly refill itself. And thus, you can get by with a pancake or hot dog compressor for these tools. Read more about the best air nailers here or this paint sprayer guide in this article.
Power is another important consideration. Shown through HP units — meaning horsepower — the motor is a key factor in how much power your compressor can supply. Horsepower ratings run anywhere from 2-10 or even 15 HP for really big compressors. For air compressors being used with electric standard power outlets, you’ll be looking at less than 2 horsepower. T his is because standard AC cords require that you only put 15 amps through for your current — or roughly 1800 watts. Your standard compressor will put out about 4 CFM at 100 PSI for each unit of horsepower you have.
CFM for Air Compressors
Finally, the CFM or cubic feet per minute are a consideration to think about when obtaining a new air compressor. The CFM is essentially how much air the unit can put out depending on its pressure valves. The rate at which the air is actually expressed is shown through CFM, varying depending on the atmospheric pressure and humidity levels. Thus you might see CFM shown as SCFM as well — meaning Standard cubic feet per minute.
Figure out your needs before picking a unit
The CFM rating is in conjunction with PSI values, so if your CFM goes up, your PSI may go down. To figure out how much size, power and CFM you need, ask yourself these key questions. What are you purchasing the compressor for, in terms of hobbies vs. business usage? How often will you use it throughout the day? What tools and equipment will it be supporting? Do you need a stationary or portable unit? Will it be supporting more than one user’s needs?
CFM requirements based on number of users and tool types
CFM requirements are shown through each air compressor, and each one has a max CFM output it can generate. Its CFM output has to be more than the requirement so that each tool will operate efficiently, without problems. In general, if you are running a pneumatic tool-based shop for example, you will need about 5 CFM per worker. A 1/2 inch impact wrench will need about 5 CFM at 90 PSI, so your compressor CFM should be larger than that.
And if you have 2 technicians operating these wrenches at the same time, you need 10 CFM minimum. The pattern of usage for these tools is to use it for about 20 to 30 seconds and then stop using it while they change the tier, while body shop mechanics might need sanders and grinders for 20 to 30 minutes per usage. You need higher CFM at constant usage levels, which is why it is so important to first figure out how you’ll be using the machine.