How to Increase CFM on Air Compressor


How to Increase CFM on Air Compressor

Air compressors are a type of machine that you will see in almost every factory that deal with various air tools including spray guns, air hoses, air riveters, machine crowns and many more.

There are basically 3 types of air compressors that you’ll find in the market;

  1. Reciprocating or Piston Compressors
  2. Rotary Vane Compressors and
  3. Rotary Screw Compressors.

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Our main focus will not be on a particular type, but a general guide on how to increase the CFM level of air compressors in general. We will be discussing two most popular methods to increase the CFM level of air compressors. Before we move forward, first we need to get acquainted with the term CFM.

What is CFM in Air Compressors?

CFM stands for Cubic Feet per Minute. It is a globally used unit to measure the amount and velocity of the air that enters into a compressor. In terms of calculating the CFM level, you must take some facts into account including the speed of the pump and size of the reservoir, i.e the cylinder.

Let’s make it clear for you. Suppose you have an air compressor with 9 CFM rating. It means that your compressor intakes 9 cubic-feet or natural air in a minute. Don’t bother yourself with the ‘rating’ just yet. It totally depends on your purpose of using.

For instance, the compressors that are used at home operate between 2-10 CFM ratings. On the other hand, the compressors that are used in factories for industrial purposes operate at 5-15 or more CFM ratings depending upon the production rate of that particular company. The more CFM a compressor has, the more powerful it is.

The Importance of CFM

The main purpose of using an air compressor is to use various tools by being in the periphery of the compressor’s pressure. So, you should know the importance of CFM before buying one. As we have mentioned earlier, the more the CFM level increases, the more powerful your compressor gets and you can have more access to air tools.

If your compressor has zero CFM ratings, it means you will get absolute zero output by using it. All that will happen is your electric bill will rise.

Similarly, if you have a compressor with a decent CFM level, you will have convenience while using air tools. If you are to meet bigger factory goals, you might have a compressor with a higher level of CFM.

Steps to Figure out the CFM Level

It is only normal to forget the CFM of your air compressor. In these scenarios, instruction manuals come in handy. But just in case you are unable to find it and it is an emergency, there is an alternative way to find it out by calculating using a small mathematical technique.

Just follow these steps and you’re good to go –

  • First, shut the machine down by turning the knob. Then carefully take note of the volume of the tank in gallons.
  • You might need a calculator here. Divide the tank volume of the compressor by 7.48 (since 7.48 gallons is equal to 1 cubic foot). This will convert your tank volume into cubic feet.
  • Make sure that the air compressor’s tank is empty at first, and then refill it again.
  • Take careful note of the time shown in the gauge while refilling the tank. It is shown as PSI which stands for Pounds per Square Inch.
  • The kick in and kick out time has to be measured properly before finding the difference between the two. For example, if the kick in time is 70% of your compressor and the kick out time is 90; you have to subtract 70 from 90. The difference will be 20 PSI.
  • Now, divide the value by 14.7 and the result you will get will be the pressure in the ATM.
  • Afterwards, multiply the pressure with the volume and then divide the result by 60. The result that will come out is the CFM. Here, the law is: CFM = Pressure × Volume / 60

Why Increasing CFM Level is Required?

Preference of CFM levels differs from one job to another. The balance between the CFM of your compressor and the type of your work is beyond essential. A perfectly accomplished outcome is only possible if your CFM is on the ideal level.

For instance, working with an air paint sprayer demands a higher level of CFM for the compressor to maintain smooth performance.  This makes it pretty obvious that you will have to modify the CFM of your air compressor just as you switch to painting from some other job which requires a different CFM level.

The main point is the wellbeing of your air compressor along with the tools you will be using. If you fail to match the desired CFM rating of your air compressor with the tools in use, chances are that you’ll end up with a ruined set overall.

Following the instruction manual provided by the manufacturer not only ensures proper setting and functioning of tools but also ensures that no hassle will occur aside from the fact that being careless with the CFM may also result in hazardous events during your job.

If you look forward to getting your work done professionally, getting the CFM levels on the right scale is very much needed. Or else, the tank will take much more time to refill than usual. And we all know that time management can be a big issue in terms of work – be it a heavyweight project or a simple one.            

 The Techniques to Increase CFM Level

Technique #1: Diminishing the Pressure

To understand this, first we have to get acquainted with the mechanism of an air compressor. First, the machine inhales air from the atmosphere and it stores it in the reservoir; i.e the tank.  This allows the machine to use the inhaled air to accelerate the pressure of the tank.

The cubic feet per meter idea refers to the level to which the stored air comes out from the hose pipes.  As all these things follow the laws of physics, the relationship between CFM and pressure is not proportional.

With that being said, if you want to increase the CFM of your air compressor, the first thing you should do is to decrease the level of pressure. There is a balance in between these two fundamental components. And if the equilibrium somehow can be fluctuated within our control, we can have access to each of the components.

Let’s make it easier for you. Suppose you have a compressor operating at 120 PSI with 7CFM. That means, as the machine reaches the 120 PSI pressure level, it will discharge 7 CFM output of air. What you have to do is just simply lower the PSI level and your CFM will increase automatically by following the laws of physics.

It is to be mentioned the change will not be something revolutionary, you might not see the change in the first place. Keep your eyes on the pressure indicating gauges as they will show you the slightest of changes if your bare eyes can’t find them.

Technique #2: Connecting Multiple Compressors

Consider a scenario where your compressor is just not being able to provide you the desired CFM level. Also, you just can’t force your machine to work beyond its capacity. So, exactly how will you do it?

The remedy is as simple as eating a piece of cake. You can connect two or more compressors to increase the overall CFM level. Suppose, you have two air compressors having 7 and 8 CFM in them respectively. If you connect these two compressors, you will have an overall CFM level of 15. Indeed a piece of cake, isn’t it?

To execute the task you’ll need an extra hose. It will be attached to the third hole. The rest of the hoses will work as the input channel and the third hose will work as the output channel. Connect the additional hose with the air tool carefully and Boom!

By adding these 2 compressors, you are expanding the level of your overall flow which will produce extra CFM. One thing to be kept in mind is that this technique takes time to work properly. One simple advice, do not lose your patience while installing the third hose. Plumb the compressors with extra care and attach the hoses carefully.

Unlike the first technique, the result can be easily seen after a day or two. The process is very simple yet effective.

 You Should Know

Testing the aforementioned techniques is effective, yes. But there are some insights that you should keep in your mind. It is because if you don’t consider these little details, you might end up damaging your compressor which will be the last thing that we want.

  • When you’re lowering the pressure, do not jump to the lowest settings in the first place. This will damage the whole energy consumption mechanism. Your machine is not used to working beyond its capacity. All you can do is to push its limits, of course slowly and steadily, don’t rush!
  • While following the second technique, keep an eye on both of the compressors. Do not allow one of them to work occasionally while the other one is overworking. This will make the whole process sloppy and the only thing will happen, is that your electric bills will be doubled.
  • For both of the techniques, the experts do not suggest nor encourage you to get rid of, change or jam/block the relief valve when you’re making small installations to the compressor. These tools are mechanically fitted for your own safety, and they help to perform the machine to its fullest. So, do not pull out anything that’s essential for your machine.
  • Before you try to increase CFM, you should figure out the existing CFM level of your machine. To do that, follow a simple formula,

CFM = Pressure * Volume/60

It is essential because you should know how much your machine can take. So, measure the existing CFM and set a goal to which you want to put your new CFM level which should be within the maximum range of your machine.

  • Don’t forget to check all the switches and pulling handles before you turn on the machine. A single mistake can ruin your compressor and it can also cause many electrical hazards.


 What is the difference between PSI and CFM?

As for abbreviation, PSI stands for Pound per Square-Inch; on the other hand CFM stands for Cubic feet per Minute. As the names suggest, PSI is the global measuring unit of pressure implied within a specific area, and CFM – the volume of air that comes out of the compressor in a particular period of time.

What is the ideal amount of CFM?

There is no specific number to determine the perfect CFM amount. It differs from tool to tool according to the needs of the user. So, it solely depends on your desire!              

How can I calculate CFM?

It is just a simple law of physics and some surface level math. You can use a simple formula;

CFM = Pressure * Volume/60.

Just measure your findings and put them in the formula and calculate yourself, no big deal!

What is the relation between PSI and CFM?

Our first method of increasing CFM level describes it all. The principal relation between these two terms is that they are not proportional. That means, if you increase one, the other one will automatically decrease.

 Will adding an extra tank be beneficial?

Well, it has a two way result. First, if you add an extra tank, it will allow you to run longer and the longer it runs, the more time you get for your air tool. The shortcoming of this is it won’t escalate your CFM level because you will need the same amount of PSI, remember the relation between PSI and CFM?


As you have come this far from the article, we hope that you have got your answers. You see, maintaining such a machine while keeping all those facts in mind is not an easy task at all. Remember, we’ve got your back. Read the article thoroughly a few times to get the theories and simply just imply them.

Contact us for any further queries; we’re always here to help you.


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