Air Compressor Buying Guide (2024)

All of the best air compressors fall into two broad categories: portable and stationary. Determining the best types of air compressors for your needs takes understanding the differences between portable and stationary air compressors.

Portable air compressors come in a variety of shapes and sizes. Smaller models are light enough to carry. Larger models include wheels for mobility. Portable air compressors are available with different sized tanks, ranging from two gallons to 30 gallons.

Designed to be bolted into a fixed area, stationary air compressors are designed to attach directly to a building's electrical circuit. They typically feature 60 to 80-gallon tanks and offer between 4 and 10-horsepower motors. They are a great investment for a garage or workshop.

Air compressors are either powered by electricity or gasoline.

Electric Air Compressors:

• Electric air compressors generally run on standard household voltage, between 110V to 120V. Compressors with motors that exceed two running horsepower require a 220V to 240V outlet.
• Since electric compressors don't emit fumes, they are the better choice for indoor applications, making them the best home garage air compressor where there's limited ventilation. They are also the best air compressor choice when you're looking for quiet air compressors or automatic start stop air compressors. Within this category, you'll also find air compressors with a rechargeable battery. Remember that powering an electric compressor with a generator can damage the motor.

Gas-Powered Air Compressors:

• Gas air compressors are generally used by builders and remodelers because of their high output and convenience at the job site. However, these types of air compressors emit exhaust and should only be operated outdoors or in well-ventilated work areas.

When matching a pneumatic tool's requirements to an air compressor's capabilities, the most important rating to consider is how much air the compressor can deliver, which is measured in standard cubic feet per minute (SCFM). Tools powered by air compressors also have SCFM ratings, which indicate the air flow required for optimal operation.

The actual SCFM changes depends on the pressure of the air in the compressor, which is represented as pounds per square inch (psi). Look for the "SCFM at 90-psi" number when comparing SCFM ratings.

Smaller tools usually require between 0- to 5-SCFM, while larger tools can require 10- or more SCFM. To gauge the minimum compressor SCFM rating you need, examine the SCFM requirements of all the tools you intend to use. Multiply the highest tool rating by 1.5 to get the minimum compressor SCFM for your needs. This gives you a little buffer, which is important, since actual SCFM varies during compressor operation.

If you expect to operate multiple pneumatic tools at the same time, you'll need more power. In this case, calculate the minimum SCFM compressor rating by adding up the SCFM requirements for each tool that you'll use simultaneously. Most light-duty home compressors are designed to power only one tool at a time, but larger professional-grade compressors can handle multiple tools.

The air pressure the compressor generates inside the tank is measured in psi. Light-duty compressors generally have 90-psi, which is typically sufficient for pneumatic tools for simple household tasks, including nailers. More powerful compressors may generate 150-psi or higher.

While not as important as the SCFM rating, a compressor's horsepower (HP) rating can give you a relative sense of the model's power. Horsepower indicates how powerful the motor is, while the SCFM rating tells you how much power the compressor actually provides to your tools. Compressors generally have horsepower ratings between 1 1/2- to 6 1/2-HP.

If you will be using air tools that require a high volume of air for continuous use, then you should consider a larger tank. If you only intend to use the tool intermittently, your compressor can have a smaller tank size. Having a large enough tank with a compressor pump that exceeds the SCFM requirement of the tools will allow the compressor time to cool between cycles.

Tools that require only quick bursts of air, like pneumatic brad nail guns and finish nail guns, drain the air tank much more slowly. For these tasks, 2- to 6-gallon tanks are sufficient.

There are two pump types: single and two-stage. You may also choose oil-lubricated or oil-free. In addition, there are other pump features that can protect both you and the compressor from harm and unnecessary wear and tear.

Below are the types of air compressor pumps you can choose:

• Single-stage air compressors can have one or more cylinders producing compressed air at the same output pressure.
• Two-stage air compressors have at least two cylinders. The first-stage cylinder(s) feed air to a second-stage cylinder that further compresses the air. The second stage cylinder(s) typically increases the tank pressure to around 175-psi. The benefit is more air stored in the same size tank, allowing tools to run longer. This is useful for high-demand work, such as continuous tool operation in an auto shop.
• Oil-lubricated air compressors require oil to operate, just like a car or lawn mower engine. The oil lubricates the moving parts in the pump to prevent excessive wear. They are generally larger and heavier than equivalent oil-free models, and oil must be monitored and changed to prevent premature failure.
• Oil-free air compressors typically use special piston rings, made from a material similar to what's used in non-stick frying pans, to lubricate the cylinder. Because there is no oil, oil-free compressors are much smaller and lighter than oil-lubricated compressors, making them a popular choice for home and job site applications where portability is important.

Once you've discovered the best air compressors for home use or workshop use, it's time to add a few key air compressor parts and accessories.

• Pressure regulator: Installing a pressure regulator on your air compressor will help you know precisely how much air flows from the compressor, making it easy to adjust the pressure up or down according to the needs of the job.
• Air hose: Many compressors come with an air hose, but if it doesn't, you'll want to get one. Sometimes you may want to trade out the air hose it comes with for a longer option for extended reach.
• Dryer: The natural moisture contained in compressed air can cause damage to pneumatic equipment over time, but adding a desiccant dryer to the air compressor can help protect your equipment.
• Air line filter: If you don't purchase a dryer for your air compressor, an air line filter is another fantastic option. It traps water, oil and dirt as you're using the air compressor, protecting pneumatic tools.
• Air compressor combo kits: Consider a combo kit if you want to get an air compressor with key accessories or a compatible pneumatic tool included.

As you browse all the types of air compressors available, consider looking for compressors with features such as:

• Air-cooling system: Cools pumping machinery to extend motor life.
• Thermal overload switch: Automatically shuts off motor if it overheats, increasing tool life and protecting your investments.
• ASME certification: Indicates high-quality material and craftsmanship, identified on the tank with a certification label stating that the unit meets the standards of the American Society of Mechanical Engineers.
• Roll cage: Protects the compressor from being crushed or battered on the job site.
• Universal quick connectors: Make easy work of trading out your tools when you purchase air compressors with universal quick connectors.

Safety Tip: Never exceed the recommended pressure for the job or the tool. With oil-lubricated compressors, always check the oil level to ensure sufficient lubrication. Make sure safety relief valves are not covered during use, as they allow air to escape automatically if pressure is too high. When done, open the drain to get rid of moisture.