Piston air compressors come in either one-stage or two-stage models. Those stages refer to the number of times the air is compressed between intake through the inlet valve and being propelled through the tool nozzle.
Put simply, a one stage compressor model compresses the air once and a two-stage compressor twice – that’s it!
Now, it’s important to clarify that the difference between multi, and one stage compressors isn’t about the number of pistons or cylinders; it’s solely related to the amount of times the same air is compressed.
In a one stage compressor, the air is:
- Drawn in through the inlet valve
- Compressed in one piston stroke
- Routed to the storage tank
- Transmitted out through the tool nozzle
A two-stage compressor will instead move the compressed air through a cooling tube. That lowers the air temperature before it is compressed again, increasing the pressure.
Having covered the basics, let’s look a little further into how one stage compressors compare and the uses for both types of equipment!
What is a One Stage Compressor Used For?
One stage compressors, by their nature, don’t produce as high an air pressure as a multi-stage model. That pressure is typically up to around 10 bar or 145 PSI.
However, that also makes a one stage compressor a much cheaper option, suited to:
- Smaller jobs, where a continual air supply isn’t required.
- Home compressor applications.
- Tools such as sanders, drills and nail guns.
A two-stage compressor is more often used in high-power industrial applications, with air pressure up to 30 bar or 435 PSI.
You might find a two-stage compressor in a lift, a ratchet, or a heavy-duty pneumatic tool.
Do I Need a One Stage Compressor or a Multi-Stage Model?
The correct compressor for you depends entirely on your compressed air requirements, and factors such as:
- The volume and duration of processes required.
- How often you use air compression.
- Space restrictions.
Air compressors are used in countless applications, and a reciprocating air compressor, or piston compressor, will come with a range of CFM outputs, tank sizes, horsepower and design specifications.
Two-stage compressors create double the pressure, but that’s not always the best solution!
For example, handheld tools or pneumatic equipment in automotive body shops are usually one stage compressors. Using too high an air pressure would make such tools more challenging to manage and produce compressed air unsuitable for the intended application.
Minimal power is required to run tools for nailing, trimming or framing, in which cases a one stage compressor is more than sufficient.
Most two-stage compressors are found in industrial applications and factories or as an energy source on a construction site where a continual air supply is required.
Given this additional capacity, a two-stage compressor is more costly than a single-stage compressor model.
Pros and Cons of a One Stage Compressor
If you’re still unsure which compressor is suitable for you, we’ll run through the pros and cons of a one stage compressor to help you make the right call!
Advantages of One Stage Compressors
- Lower cost to purchase and install.
- Remain reliable and efficient air compression tools.
- Available from a broad range of manufacturers.
- Come in various HP sizes, usually from three HP up to 600 HP.
- Versatile equipment used in many air compression applications.
- Flexible options, such as open or enclosed, tank-mounted and integral dryer designs.
- Multiple control methods.
- They are easier to maintain, with only one cylinder used for compression.
- Less energy is required to run the equipment (although one stage compressors are slightly less energy efficient overall, as explored below).
- Single-stage piston compressors generate less heat by utilising more air, so they are more appropriate for smaller workshop spaces.
Disadvantages of One Stage Compressors
Most of the downsides to opting for a single-stage compressor relate to the output air pressure and dictate whether this type of compressor is suited to the required applications.
- Rapid cycling (turning the compressor on and off again repeatedly) is inefficient.
- The lifecycle is typically shorter than a two-stage compressor.
- Limitations on PSI compressed air outputs and power restrictions, usually to 15 KW.
- One stage compressors are not suited to continual air requirements or for heavy-duty industries.
Dual-stage compressors are also more energy-efficient since the air is cooled between compression stages, meaning less energy is needed to compress the same air volume to more significant pressure.
However, as we’ve discovered, that depends on the air requirements of your tools, machinery and processes, so a lower-cost one stage compressor may still be the most economical option.