As a person interested in doing DIY work around the house, you probably have one big question popping around in your head: what air compressor size should I get for my air tools? Unless you get a good-sized air compressor, there is a high chance it might not give you the benefits that you want. If it is too small, it won’t provide the compression power that you need. On the other hand, if it’s too big, you’ll be investing in something you might not need.
This is why you must get the perfectly sized air compressor. Since manufacturers tend to make different ranges and styles for air compressors, there are various choices for you to go for. You just need to determine your needs, along with the air tools that you are planning to use.
Don’t Be Fooled by the Physical Size
At this point, you are not looking at the physical size of your air compressor – but instead, at the air output. You might think that bigger is always better, but in most cases, it is not. You might find huge air compressors with quite a low air output just like you can find small air compressors with a very high air output.
Most new models were made to be quite powerful while retaining the compact size. You need to consider the storage space available – and most importantly, read the label of the product.
Determining Your CFM Needs
Rather than determining the size of the compressor by looking at how big it is, you might want to determine its size by looking at its CFM (cubic feet per minute) for the airflow. No matter if you get a 12V air compressor or a 24V one, the requirements will be visible.
Each air tool will need a different CFM rating. For example, industrial application tools require higher CFM, whereas low CFM is useful only for light-duty tasks (such as inflating a passenger tire). The average power tool can use anything from 30 to 140 CFM, depending on the unit. Other units might require even less power, depending on their features.
The CFM you choose will generally depend on the specifications of the power tool that you are planning to use (the user manual will tell you exactly how much you will need). However, if you plan on using multiple air tools, then you might want to combine their CFM and get the perfectly sized one.
Once you know the CFM required by your specific air tools, you’ll also know what size air compressor you need to get. Ideally, you should find a compressor that meets the air output, without exaggerating the numbers.
Keep in mind that while you do need to pay closer attention to the CFM, you also need to consider the storage tank size and maximum pressure. Make sure that the CFM output of your unit of choice is around 25% bigger than the total output needed for your air tools.
Considering the PSI for the Unit
Depending on the air compressor that you buy, it will have a transferable CFM at a certain PSI rating. These ratings are given based on the tank size, the horsepower, and the tank capacity. Obviously, the higher the PSI, the more it will be able to compress the air and give you the power that you need.
You must also consider whether you need a single-stage compressor or a two-stage kind – and here, it will be the type of pump that is of utmost importance. A single-stage pump can deliver on average about 155 PSI, whereas a two-stage pump can go as high as 175 PSI.
Like with the CFM, you also need to consider the specific air tool requirements. Bear in mind that if a unit asks for a higher PSI, it doesn’t mean that it will need a higher CFM as well.
For example, an air hammer will have a required PSI of 90-100, with the CFM rating at 4. Those numbers change at 60-125 PSI and 70 CFM for a sandblaster.
Specific Air Tools and Their Power Needs
In most cases, you will be able to determine the size needed for your air compressor by reading through the tool’s specifications. That being said, each type of air tool will have an average air output need, allowing you to choose the perfectly sized air compressor.
An air drill that has a 3/8-inch chuck capacity will generally need 4-7 CFM in order to get started. On the other hand, an airpower drill that has a 1/2 capacity will need around 6-8 CFM at about 90 PSI.
Grinding tools generally operate in the same manner as drilling tools, with just a few differences. A grinder that has the power to start a 7-inch size grinding disk will generally need about 7 CFM at 90 PSI.
The air chisel is one more air tool that you can commonly find in a household. In order to operate this unit, the air compressor needs to deliver 4-8 CFM at 90 PSI. A needle scaler will also work pretty much in the same way, and it will need almost the same CFM.
From all mechanical tools, the most important one is the impact wrench. A ½-inch drive impact wrench (the most popular kind) will require about 5 CFM, whereas bigger ¾-inch wrenches will need an average of 8-11 CFM.
In the end, finding the right size air compressor is not that difficult, as long as you know the requirements for your power tools. If you plan on using multiple units, just figure out their CFM and PSI output, add them, and then buy an air compressor based on that result. You don’t necessarily need a bigger one, but make sure that it supports all of your power requirements.