Single stage reciprocating air compressors

Single stage reciprocating air compressors are perfect for light work at home and/or in small workshops. I would not recommend a standard single stage unit for commercial use.

Most single stage units will work happily for years if you don’t use them too much, for example in a one-man workshop. But if you require more are (two-man workshop) or use a lot of power tools (compressed air powered grinders, drills, etc), than a double-stage compressor would be better suited for you.

There are a few things to consider when buying a single stage unit. Things like pressure and capacity are of course important, as they are for any kind of compressor.

But there are some single-stage specific points to keep in mind. Why? Because the single-stage air compressor market is filled with misinformation, low-quality products and misleading product information!

There are a lot of people shopping for single-stage air compressors, and many people don’t know the details or what to look for. That’s also why I created this air compressor buying guide!

Things to check before buying a single-stage air compressor

Maximum pressure

Of course, check the maximum pressure. Keep in mind that if you buy a compressor with a higher maximum pressure than you need, you can always lower the pressure setpoint.

Or, you can keep the higher pressure and use the pressure reducer to reduce the pressure to the pressure you need.This way you have an extra buffer. Great if you have big air tools that require a lot of compressed air and you only need them for a minute or two.

Keep in mind, that pumping up to an higher pressure will costs you a lot more electricity. If you don’t use it frequently this is not a problem, but keep it in mind if you use compressed air frequently.

If you don’t know what pressure you need, start at my air compressor buying guide main page.

Capacity

The capacity of the compressor is the amount of air that is produced by the compressor.

Most people will know what pressure they need, but are unsure of the capacity. If you don’t know what capacity you need, start at my air compressor buying guide main page.

A lot of online air compressor stores will advertise by the size of the air tank, for example ‘this is a 60 gallon air compressor’. I also see this a lot in online forums.

Yes, it’s an air compressor with a 60 gallon tank, but what is the capacity?

Remember, capacity is in cubic foot per minute (cfm). Tank size is in cubic foot, or gallons.

Horse power

Horsepower or engine power (in HP or kW) is not really important. It’s just something that follows naturally given the pressure and capacity of the compressor.

For X amount of capacity/air flow at Y pressure, we need a certain amount of power. It’s all physics, cannot change it.

Since we know the pressure and capacity we need, horsepower is not really important. Besides, lot’s of manufacturers will ‘exaggerate’ (or you can say ‘ lie’ ) the horsepower of the machine. This is especially true for the smaller piston type compressors.

Most people think bigger = better.

Lot’s of brands and shops will use terms like ‘peak horse power’, which is technically a wrong term. When a compressor (or any machine) starts up, it draws 3 – 7 times the normal electrical power, but for only a few seconds. Some brands take this ‘peak’ current and calculate it into their ‘peak horse power’, which is completely nonsense!

Tank size

Most industrial/commercial grade single-stage air compressors come with a 60 gallons air tank.

I can fit a very small compressor on a very big tank. Or I can fit a very big compressor on a very small tank. In fact, I see this a lot: a very small capacity air compressor, installed on a very big air tank. The unit is than sold at the price of an high-capacity unit!

The size of the tanks says nothing about the capacity of the compressor! It is simply the compressed air buffer you have.

Bigger tank vs smaller tank

With a bigger tank, the compressor will start less frequently, but it takes longer to fill up the tank to the required pressure. On the other hand, you can use your air tools longer, before the compressor starts up again.

With a small tank, the compressor will start frequently and the tank is filled up very quickly.

A bigger tank size is better. But don’t just look at the tank size only, the capacity (cfm) of the compressor is more important.

Duty cycle

air compressor duty cycle Duty cycle is a number between 0 and 1 (or 0 to 100%) that shows how long the compressor can run during any given period.

For example, a duty cycle of 30% means that the compressor can rub for 30% of the time, but needs to cool down the remaining 70%.

For professional grade compressors, and especially for rotary screw compressors, the duty factor is of no importance. They can run 24 hours a day for years without stopping (well, for maintenance only). The duty cycle is 1 or 100% in this case.

For example, when the maximum duty cycle of the compressor is 50%, it means that the compressor needs to be stopped during 50% of the time. This time is required to cool down the compressor. If it runs too much, it overheats and breaks down.

A lot of single stage units have a duty cycle of 50%. But this is not always clear from the product description. Always ask what the duty cycle is it is not explicitly states.

Often I see the following: when the duty cycle is 100%, is says so in the product description. If the duty cycle is less than 100% (often 50%), the duty cycle is nowhere mentioned in the product description!

 In my opinion, a duty-cycle of less than 100% is a sign of a low-grade air compressor. It’s like buying a car that needs to cool down for 15 minutes after every hour of driving.

If you buy such a compressor, you need to over-size them according to your (average) air demand. The compressor will fill up the tank and stops to cool down, while you can continue using compressed air (stored in the tank). Hopefully it cooled down enough before your storage tanks runs out of pressure…

Where are they made?

I know people value the ‘made in the USA’ air compressors. While I can understand this, it’s not as simple as that.

A compressors consists of many, many different parts. With most air compressors, at least some parts are from China or India.

Secondly, some air compressors are ‘Assembled in the USA’, but the individual parts are imported from other countries.

This doesn’t necessarily means it’s low quality, just the manufacturer is trying to trick you 🙂

Here is what I was able to find out:

Quincy

Pump, motor and tank are made in the USA.

Ingersoll Rand

Ingersoll Rand single/double stage air compressors are ‘assembled in the United States’. But, the individual parts come from other countires:

  • The pump is made in China or India
  • The electrical motor is made in from Mexico

Campbell Hausfeld

If the pump has ‘made in the usa’ cast into it, it is made in the USA. If not, it is imported from China or Inda.

I am not sure about the motor and tank.

Husky

Husky compressors are the same as Campbell Hausfeld.

Atlas Copco

Atlas Copco compressors are either made in Belgium or Italy.