Should I choose a piston or screw compressor?

May 7, 2020

5 minutes

Piston (reciprocating) compressors and rotary screw air compressors are two of the most popular compressor technologies available today. But do you know which one would be better suited for your specific needs and applications? Understanding the difference between piston and rotary screw air compressors and the capabilities of each technology is key. That’s why we’re covering the basics below!

What factors should I consider?

Initial and operating costs, energy efficiency, duty cycle, and service intervals are important factors to consider when determining whether your business will benefit most from a piston or a rotary screw compressor. Noise levels is an additional factor to take into consideration.

Initial cost vs. operating costs. Budgeting for a compressor shouldn’t only include how much you pay for your compressor upfront; you also need to consider how much you’ll pay for your compressor in the long run (i.e. your overall operating costs). As much as 70-75% of a compressor’s lifetime operating costs are spent on energy usage, so keep that in mind when selecting a compressor technology. Pistons have a lower initial cost than screws, but screws cost much less to operate over time.
Energy efficiency. If both a piston and a screw were running the same amount of hours, the screw compressor will be much more efficient and have lower operating costs than the piston over the lifetime of the compressor. When selecting a technology, ask yourself: Is the initial or lifetime cost more important to you and your business?
Duty cycle. Because piston compressors are limited in their duty cycles, they’re ideal for applications with low duty cycle requirements and low daily running hours. Screw compressors, however, have long duty cycles. In fact, screws are engineered to run 100%, all day, every day!
Service intervals. There are more moving parts in a piston compressor than in a screw, which results in increased machine wear and tear. Screw compressors don’t have as much wear; hence, they have reduced maintenance needs. But keep in mind that it’s important to keep any type of compressor on a consistent maintenance schedule! This will help ensure machine efficiency and optimal system performance.
Noise levels. Piston compressors are loud – especially in comparison to screw technology. If you’re looking for a lower-noise machine or a low noise level is required, you may want to consider a screw compressor.

Piston vs. rotary screw compressor: a side-by-side comparison

To make the right choice between a piston and a rotary screw compressor, it helps to see how the two technologies stack up directly across the factors that matter most to your operation:

How they work: A piston compressor uses a reciprocating piston driven by a crankshaft to draw air into a cylinder and compress it with each stroke. It is a well-established mechanical design that has been used in industry for well over a century. A rotary screw compressor uses two interlocking helical rotors that continuously trap and compress air as they rotate, delivering a smooth, continuous flow of compressed air with no reciprocating motion.

Output consistency: The reciprocating action of a piston compressor produces compressed air in pulses rather than a continuous stream. This can cause pressure fluctuations in the system, which may affect the performance of sensitive downstream equipment. A rotary screw compressor delivers a steady, continuous flow of compressed air, resulting in more stable system pressure and more consistent performance for tools and processes.

Size and footprint: Piston compressors tend to have a larger footprint relative to their output compared to rotary screw compressors. Rotary screw compressors are designed to be compact and space-efficient, making them a better fit for facilities where floor space is at a premium.

Application fit: Piston compressors are well suited for intermittent use, lower CFM requirements, and applications where upfront cost is the primary concern. Rotary screw compressors are the preferred choice for continuous or heavy-duty operations, higher CFM demands, and facilities where energy efficiency, noise levels, and long-term operating costs are the priority.

The recap

Piston air compressors a great option as an entry level compressor, but it's common for facilities outgrow the unit. If you need a consistent and or increased flow (CFM) and are looking for something that is compact, efficient, reliable and quiet, going with a rotary screw would be a great option. It’s quite normal for a company to start out with limited need for compressed air, but as production and customer demand increases, so does the need for increased output and the need for a larger compressor that can adequately handle the demand and increased duty cycle!

Still struggling with which technology is right for you? Our compressed air experts are always available to talk you through the decision! Give us a shout at www.atlascopco.com/air-usa!

Frequently asked questions

What is the main difference between a piston and a rotary screw compressor?

The main difference between a piston and a rotary screw compressor lies in how they compress air. A piston compressor uses a reciprocating piston to compress air in pulses inside a cylinder, while a rotary screw compressor uses two interlocking helical rotors to deliver a continuous, smooth flow of compressed air. This fundamental difference affects everything from energy efficiency and noise levels to duty cycle capability and long-term operating costs, making each technology better suited for different types of applications.

Which is more energy efficient, a piston or a rotary screw compressor?

A rotary screw compressor is significantly more energy efficient than a piston compressor, particularly in applications that require continuous or high-duty-cycle operation. Because as much as 70 to 75 percent of a compressor's lifetime cost is spent on energy, the efficiency advantage of a rotary screw compressor typically results in substantially lower total cost of ownership over time, even though its initial purchase price is higher than a comparable piston compressor.

Can a piston compressor run continuously like a rotary screw compressor?

No. Piston compressors are not designed for continuous operation and have limited duty cycles, meaning they require rest periods between operating cycles to prevent overheating and excessive wear. Rotary screw compressors, by contrast, are engineered to run continuously at 100 percent duty cycle, all day, every day, making them the right choice for facilities with continuous or high-demand compressed air requirements.

Is a piston compressor suitable for a professional workshop or industrial facility?

A piston compressor can be a suitable entry-level choice for a professional workshop or light industrial facility where compressed air demand is moderate and intermittent. However, as production demands grow and duty cycle requirements increase, many facilities find that a piston compressor can no longer keep up, and upgrading to a rotary screw compressor becomes necessary. If continuous, high-volume compressed air is already a requirement, starting with a rotary screw compressor is the more practical and cost-effective long-term decision.

Which compressor is quieter, a piston or a rotary screw?

Rotary screw compressors are significantly quieter than piston compressors. Piston compressors generate considerable noise due to the reciprocating motion of the pistons and the associated mechanical vibration, which can be disruptive in a shared workspace or facility. Rotary screw compressors operate much more smoothly and quietly, making them the preferred choice for noise-sensitive environments or facilities where operator comfort and workplace noise regulations are a consideration.

When should I upgrade from a piston compressor to a rotary screw compressor?

It is time to consider upgrading from a piston to a rotary screw compressor when your compressed air demand has grown beyond what your piston compressor can reliably handle, when your duty cycle requirements have increased to the point that the piston compressor is running excessively hot or struggling to keep up, when energy costs have become a significant concern, or when noise levels from the piston compressor are causing workplace issues. Many businesses start out with a piston compressor and naturally transition to a rotary screw as their operations scale. An Atlas Copco compressed air expert can help you evaluate whether your current compressor is still the right fit and recommend the best upgrade path for your specific needs.