You may be a home DIY enthusiast or a professional mechanic; there’s a considerable possibility that air compressors and air tools are a crucial part of your work life. Air compressors are versatile machines with a wide range of applications and valuable in many different sectors. For instance, air tools like nail guns for woodworking or spray paint guns for auto painting (and many others) need the compressed air supply according to the project requirement from an air compressor to power them.

Different types of works need different levels of air supply, and each air compressor application has a distinct air pressure requirement. No machine can do all jobs. So, even for a compressor, as versatile it may be, it would be unwise to think that every type of work can be accomplished with just a single type of air compressor. This is why there are many different types of compressors available based on the air compressor tank size, the motor size, the power level of the air compressor motor, air pressure level, or the air compression method. And it is crucial for all the compressor users to know these because these will help them figure out which air compressor will be the best suited for their respective works. For instance, if you need to work with high CFM tools often, then you should buy one with that level of capacity.

air compressors in factory

But, you may have already considered this and bought a compressor according to your project requirement. Despite that, a situation may arise when you need a higher level of CFM output to run your air compressor operation. How do you achieve that? How to increase air compressor CFM? This is the million dollar question that we’ve answered in this article.

What is CFM?

If you are one of the regular air compressor users, then you must be already familiar with the terms like CFM, PSI (pound per square inch), and HP (horsepower). But if you are not, then here are some basics about CFM for you.

CFM stands for cubic feet per minute. It represents the air compressor flow rate. The air compressor CFM can be defined as the measurement of the speed of the air that gets out of the compressor or can also be defined as the volume of air that gets out of the compressor per minute.

Let me explain it with an example. Suppose you have a compressor that has a rating of 20 CFM. What this means is, 20 cubic feet of air will come out of your compressor as other compressed air output every minute.

CFM of an air compressor is calculated using two things. One is the size of the air compressor pumps cylinder, and the other one is the speed at which the air compressor pump operates. This is not a metric measurement; it’s an imperial measurement.

how to increase cfm on air compressor infographics

How to Increase CFM on Air Compressor?

Air compressors generally come with a specific CFM for a distinct level of pressure. However, there might come some situations where you need to work with heavier tools that require higher air pressure, or maybe you are in need of using more than usual air tools. These situations may demand a higher CFM level than your current air compressor is capable of providing.

So, How can you increase the CFM of your air compressing device to fulfill the CFM requirements of these kinds of situations? Can you even do it?

Well, I’ll be answering these questions in reverse. The answer to the second question would be yes. Yes, you can increase the CFM of your air compressing device.

Now to the first question of how you can achieve this.

You can follow these methods –

  • Decreasing the air pressure
  • Connecting two air compressors
  • Allowing more time to the compressor

Decreasing the air pressure for more CFM

decreasing the air compressor pressure

After taking the atmospheric air in, a compressor machine pressurizes and compresses the air. The compressor supply pressure forces the compressor air out at a specific but adjustable rate. This is what we call the CFM, and maintaining different CFM settings is possible for compressing machines but in a particular range that defines the machine’s capability.

Every one of these machines has its own specific power level. This power level is set by the tank pressure and the CFM of the machine.

If we use the language of mathematics, then

Power = Pressure x (Volume/Time)

However, we’ve already discussed that air volume/time is actually CFM, where cubic feet is the compressors air volume and minute is the time.

So,
Power = Pressure x CFM

To maintain this constant level of power, a balance is maintained between the pressure and the CFM. This means that if you need to increase the CFM, then you have to decrease the pressure.

If you dial down the pressure regulator, the incoming air flow into the air tank will be slowed down. As a result, the pressure will decrease.

For example, let’s say that you have an air compressing machine with a CFM rating of 10 CFM at a pressure of 80 PSI. This means that when the pressure level is 80 PSI it can provide an airflow rate or air output volume of 10 CFM. So, if you want to increase the CFM to more than 10 CFM, then you have to drop the pressure and operate at a lower pressure than 80 PSI.

Connecting two air compressors for more CFM

You can decrease the air pressure to increase the CFM of an air compressing machine. But you can reduce the pressure only so much. So, using the previous method, it is not possible to increase the CFM level beyond the maximum capacity of your compressing machine. It’s not possible to run a machine beyond its power limit.

So, in case you have to go beyond the maximum limit of the current compression of your machine, you can follow this method.

Now, let’s learn how to connect an additional compressor to increase the CFM output.

First, the air tanks of the two compressors have to be connected with two different separate hoses. Then, you need to take another extra hose and join the first two hoses with the third one. The additional hose (the third one) that you’ll be using needs to have three holes. Two of those holes will be used as the inputs, and the third hole will be used as the output. Finally, take the output of the third hose and connect it with your pneumatic tools. That’s it. You are done. This method will help you increase the CFM beyond the maximum air capacity of the machine, and the additional storage will provide your system with an increased compressed air capacity and also enable your system to run for a longer period of time.


However, there’s a downside to this method. It will take more time to fill the two air tanks with air. Also, there’s a risk of overheating along with other maintenance issues.

Allowing more time to the compressor

Allowing your machine more time to work on compressed air is another way of increasing your CFM level. This may not provide you with the best result, but this is the simplest and comparatively less expensive way of improving the CFM of your device.

In this method, you will have to dial down the pressure regulator to its lowest settings. Because of this, the compressor motor will run for a longer time. This will ensure that the density of the compressed air is higher. As a result, you will get a higher level of CFM.

If you need a slight improvement in your CFM, then allowing the compressor time is the simplest way to do it. Another added benefit of this method is that it will improve the life expectancy of your device. However, if you need a larger amount of increment in the CFM level, then this method will not be much useful to you.

Note: One important thing to keep in mind is that you should not go for the lowest setting of pressure right away. You should take time. You should gradually reduce the pressure over time and ensure the highest CFM output possible by using this method.

How to decrease CFM of Air Compressors?

Since we’ve talked so much about increasing the CFM level of the air compressors, why not also learn what to do if there’s a need to decrease the machine’s CFM. You can do that by filling up the compressor tank with air quickly. Just turn the compressor regulator to higher positions to increase the pressure and fill up the air sharp.

However, you’ll have to be careful when decreasing the air compressor CFM rating. If the CFM level drops too much, then the machine will be incapable of filling up the air compressor tank, and the pneumatic tools will not be able to run due to the lack of air supply.

Final words

An air compressor is an essential tool for a wide variety of people with applications in various different fields. However, even this useful tool can become a nuisance if you don’t choose a machine with features and characteristics required according to your need. So, don’t be hasty, think carefully, and choose deliberately. Evaluate your works and figure out if you need a high CFM air compressor or a low CFM compressor.

But, even after all these, there might come up an exceptional situation where you need an increased CFM output for your operation, even beyond your compressor limit. And, we hope that this article will help you resolve these kinds of situations.

Thank you for reading. Good luck!

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Author

Hi, and welcome to Toolented. My name is Michael D. Sanders. I am a Mechanical Engineer by degree, who is a blogger by passion, and this combination of knowledge and passion is what brought Toolented to life. On my blog website, you will find necessary information about your needed automotive tools, reviews of your potential choices, and comparisons between different types of tools. To learn more click here.

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