If you’ve noticed that you’re not getting the airflow that you want from your air compressor, it can be frustrating. The good news is that increasing CFM on an air compressor isn’t difficult, and there are a number of things that can be done to accomplish this.
The pressure that comes out of an air compressor is measured by a unique unit known as CFM, or cubic feet per minute. Specifically, an air compressor’s CFM refers to the amount of pressure that a unit can produce at a given air pressure level.
You can increase CFM on an air compressor by around 10% by decreasing the pressure, adjusting the regulator valve, connecting two machines, or adding a receiver tank.
Finding the method of increasing your air compressor’s CFM largely depends on what works for you. Generally speaking, the most cost-efficient and easiest way to accomplish this is to buy a second air compressor and hook it up to the original. While servicing your air compressor is certainly cost-effective, it may result in additional repairs that are costly.
4 Ways To Increase Air Compressor Capacity
1. Reducing The Air Compressor Output Pressure
Increasing the output airflow of your air compressor is directly tied to reducing the output pressure being placed on it. Makes sense, right? A fully-pressurized air compressor maintains a certain capacity that is usable until the compressor turns back on again and begins to refill.
If you can get your tank pressure higher than the output pressure, you can then increase the volume of air that can leave your tank at one time.
You can calculate how this change will affect your air compressor’s CFMs by using the following equation: Old Pressure x CFM = New Pressure x CFM. When the output pressure is lower any connected tool can be used for a longer period of time.
For example, if your air compressor has a 3 CFM rating at 80 PSI, you should be able to power a device that operates at 5 CFM with 60 PSI.
This method also ensures the reliability of the compressor by not overworking it. As long as your tools require a lower PSI than your air compressor, this is a great option to increase CFM.
2. Making a Change to Your Outlet Size
While it’s important to consider that some air tools require a certain amount of pressure to operate,if you can decrease your outlet pressure enough you can often increase the airflow of your compressor. By increasing an air compressor’s outlet hose size, the outlet air flow can actually be increased.
Yet, air friction will increase as a result of this change which, in turn, slows down the air flow. If this change will result in a big enough change to make it worth the transition, it’s a fairly easy adjustment to make over other options.
To do this:
- Get a regulator gauge that measures air pressure between 0 – 150 PSI. Hook it up to the standard main valve on your air compressor, which should be set to 100 PSI.
- Turn the regulator screw until it matches the desired output of 130 PSI (usually marked right on your regular main valve body).
- Hook up the regulator gauge again; however, don’t make any adjustments this time.
- Turn the main valve control to 130 PSI.
- Now, turn the regulator screw back until it matches up with 150 on your gauge. Most gauges are accurate +/- 2%.
- This should give you about a 6% increase in CFM depending on the specific compressor and air tank size.
3. Use Two Air Compressors Together
Although it may sound like a silly resolution, using two air compressors parallel to one another can actually increase your total airflow. To be successful at this, you’ll have to set each of the compressors next to each other and connect them with fittings and hoses.
Two air compressors that can produce the same pressure at the same rate have the result of creating the air flow CFM you need as the end result.
While this won’t actually increase the CFM of the original compressor, it will do in a pinch to get the total airflow you need. You won’t see the CFM doubled, though, as some air pressure may be lost in the essential connections.
Connecting two compressors together in parallel will give the same CFM for both compressors, but one of them will have more PSI than the other. Joining two compressors in series means that both compressors will share PSI between them. If one has 10 PSI and the other 20 PSI, they can provide up to 30 PSI when connected together in series.
To do this:
- Use a t-piece air fitting to connect the outlets of both air receiver tanks.
- Attach the compressed air hose to the outlet of the t-piece.
- Lastly, connect the air hose to your power tool of choice.
When you purchase a second air compressor to hook up to an existing compressor, you won’t have to buy one that is substantially larger. One that is the same size as your current compressor or slightly larger will do. Hooking up two air compressors is quick and easy. However, it may be costly.
4. Use an Auxiliary Tank
Reducing the pressure in your air compressor’s regulator is the number one way to increase its CFMs. Using an auxiliary tank to accomplish this purpose follows the same theory used in addressing low CFMs by reducing your outlet pressure.
The volume of an auxiliary tank is higher than that of your air compressor, so pressure drops at a slower pace which allows for airflow for a longer period of time.
Adding another receiver tank will increase your air compressor’s running time and amount of CFM. For example, if your air compressor has a CFM of 5 with its original tank, attaching another receiver tank can increase its overall CFM to 10.
To do this:
- Attach the air hose to your compressor’s outlet.
- Add an additional receiver tank to your machine, ensuring it is compatible (PSI limit, size, etc.).
- Connect the regulator and pressure switch to both tanks.
- Turn on the main power supply and adjust the pressure settings for both tanks.
Service Your Air Compressor to Improve Efficiency
Inefficiencies in your air compressor is one of the most tried and true ways to inadvertently reduce your compressor’s CFM. If there is no air coming out of the hose that is attached to your air compressor, then a loss of CFM may be obvious.
Yet, smaller cracks and gaps may not be as noticeable, as they just reduce your air compressor’s CFM slightly over time. Tightening threaded fittings, using plumber’s tape to seal leaks, and working to prevent over-torquing of fittings is key.
Does a Higher CFM Make an Air Compressor Better?
A higher CFM doesn’t necessarily make anyone air compressor better than another. It really depends on the use and application you intend your air compressor to be used for. Larger air compressors that are used for commercial applications tend to have a higher CFM. Compressors with a higher rating usually can provide more air, which is why they have higher CFM ratings.
When using an air compressor for personal purposes, a CFM of 0-5 at 70-90 psi (pounds per square inch) is adequate. Commercial systems that are stationary and may have multiple tools hooked up to them average 10 CFM, or more, at 100-120 psi.
Now, if you have two air compressors with the same motor, then the air compressor with the higher CFM would be considered a “better” option. Other factors, including compression, should also be considered in conjunction with CFM in determining a winner between two competing air compressors.
What is a Good CFM Rating for an Air Compressor?
Determining what a “good” CFM rating for an air compressor would be wholly depends on what its intended use would be. Again, this is not just a straightforward answer for every buyer.
For the most part, air compressors intended for home use will have a CFM rating that ranges from 0.5 to 5. This is sufficient for DIY home projects and airing up tires. This is based on a 25% duty rating, because most home-use air compressors don’t need to be run continuously, or even frequently.
When you get into commercial use for an air compressor, the required CFM may vary. Take a look at the chart below to see how much CFM we suggest for various commercial applications.
Air Compressor CFM Requirements by Application
|Angle Grinding(Using a 7-inch Angle Grinder)||5-8 CFM||90|
|Dual Sanding||11-13 CFM||90|
|Frame Nailing||2.2 CFM||90|
|Air HammersDie Grinders¾” Impact WrenchRatchets||30-40 CFM||90|
|Sanders1” Impact Wrench||60-70 CFM||90|
|60-Lb. Pavement Breaker||60-70 CFM||90|
|Pneumatic Saws 90-Lb. Pavement Breaker||90-100 CFM||90|
|#5 Spline Impact Wrench||90-100 CFM||90|
What Happens if Air Compressor CFM is Too Low?
It can be difficult to know just how much air pressure you need your air compressor to produce to operate your air tools, especially if they are new or you aren’t familiar with their use.
If you have too little CFM you may not be able to use your air tools efficiently or at all. This would be devastating for a tradesman who relies on their tools to run efficiently for their job. It may even mean you have overspent on an air compressor that isn’t sufficient enough for its intended use.
By identifying the most common use for your air compressor before purchasing it you can avoid buying an air compressor that produces a CFM rate that is too low. By following this chart, you can see how much CFM different types of air tools will need to operate effectively.
To recap, you can increase an air compressor CFM by hooking two compressors together, properly servicing your air compressor, reducing output pressure, changing the outlet size, or using an auxiliary tank. There are pros and cons to each method of increasing air compressor CFM rates, so each should be evaluated thoroughly before making a decision.
While you can always increase an air compressor’s CFM or buy an air compressor with a higher CFM, this doesn’t necessarily mean the air compressor will be “better.”
The CFM rate of an air compressor and its adequacy will depend on a variety of factors. It is important to note, though, that a higher CFM rate will likely be relevant to a commercial-grade air compressor and not a home-use air compressor.