Piston Vs. Rotary Screw Air Compressors: Which One to Choose?

Air compressors have diverse applications for a wide range of businesses. Two of the most popular and widely used compressors are piston and rotary screw compressors.

Piston, also known as reciprocating compressors, find maximum use in the automotive service industry such as gas stations, tire stores, and general service shops, due to their price and availability. However, rotary screw compressors can be a suitable alternative as they offer better performance and require less space.

In this blog, we will understand the various points of difference between the two to help you choose the right one for your business.

Duty Cycle and Flow

Duty cycle is the time (calculated in percentage) a compressor can operate for, without getting overheated or causing wear. The allowable duty cycle for most piston compressors is 60-70%. Most piston compressors are oversized to allow space for the compressor to shut down and cool off due to the high temperatures. This may cause capacity problems during peak operating hours.

Modern rotary screw compressors, on the other hand, have in-built aftercoolers with huge surface area and robust fans to bring down the air temperature leaving the compressor.

Oil Carry-over

When pistons, cylinders, valves, and rings experience wear and tear, the quantity of air goes down. This causes more lubricating oil to seep through the piping into the usable parts. This is known as carry-over.

Piston compressors usually pass more oil than rotary screw compressors. Rotary screw compressors experience lesser oil seepage in comparison because the rotors don’t come in contact with each other and hence, don’t wear. Moreover, the compressor fluid also acts as non-wearing sealant that’s captured, filtered, cooled, and recirculated.

Energy Efficiency

For service industries that use compressors as large as 30 hp, energy efficiency becomes an essential factor to save electricity costs.

Piston compressors usually deliver 3-4 cfm per hp whereas rotary compressors deliver 4-5 cfm per hp. This shows that rotary compressors deliver more air per unit of input energy.


The maintenance of piston compressors is more expensive than screw compressors because the frequency of maintenance and the number of spares is significantly higher for piston compressors. However, the advantage is that any semi-skilled technician or worker will be able to perform the maintenance service.

Noise Levels and Vibration

Traditional piston compressors produce a lot of noise and vibration. As a result, they are mostly placed in separate rooms or outside. However, the immediate ecosystem directly affects a compressor. For example, a hot and humid room will increase the compressor temperature, reduce its shelf life and make it difficult to remove moisture and oil from compressed air.

Rotary compressors cause lesser noise and vibration. They also don’t need to be kept in separate rooms or sealed to the floor, offering more flexibility with their location i.e., well-ventilated areas.

For assistance with deciding on the air compressor that suits your needs the best, please contact us on +919819907445. We would be delighted to help you find the best product or service based on your exact requirements. As one of the leading ELGi air compressor dealers, VEMC provides a comprehensive array of seamless products and services to its clients. A pioneer in electromechanical engineering products, allied equipment, and services in the field, we are also ISO 9001:2015 certified.

Understanding The Cost of Compressed Air

Compressed air is an indispensable part of most industries. Without it, entire sectors of production would be defunct! It is so essential that it is referred to as the ‘fourth utility,’ after electricity, water, and gas. However, there is a significant cost attached to it. In fact, about 10% of the electricity consumed industrially goes to generating and using compressed air.

Keeping industrial units supplied with compressed air costs a substantial amount of money. So, it would be prudent for businesses to focus on the consumption of energy, which makes up the majority of the cost of generating compressed air. Energy consumption costs are much higher than the initial cost of air compressors or their maintenance. A whopping 80% of the total cost of the compressed air system will be from the electricity it uses up. Because this is such a huge percentage, determining the cost of compressed air becomes important in order to minimize waste heat and electricity bills.

To identify the ways that you can save such costs, take a look at your business’s requirements of compressed air as well as the components of your compressed air system, along with all the associated costs. When you do this, make sure to account not just for your business’s current system, but also for the one you envision to be in place in the future. Plan for the longer-term demands rather than just the current ones.

Here’s an overview of the components in a compressed air system that you need to look at:

Air compressors

Aim to have an energy-efficient air compressor rather than one that just carries a lower price tag. As mentioned earlier, the initial cost is just a small fraction of the total cost.

Dryers and filters

Compressed air has contaminants that, depending on the application at hand, need to be filtered. There is an additional cost and equipment to this process, so be mindful of that.


Drains remove the collected condensate of the compressed air system as required.


A good piping system is crucial for smooth movement of the air and eliminates air restrictions, leakages, and pressure drops.


Ventilation is key to cutting down heat circulation to subsequently reduce energy consumption.

Air leakage

It is of paramount importance to detect and fix any air leaks because these can have a heavy cost otherwise. Monitor your air compressor constantly to prevent this from occurring.

Central controller

In systems that consist of more than one air compressor, a central controller may play a big part. It can decrease the average pressure band (a pressure reduction by one bar reduces energy usage by 7%), regulate the compressor speed, and control compressor capacity.

A streamlined air compressor system strategy can help you reduce your operational costs significantly, so plan ahead and reap the benefits!

VEMC is ISO 9001:2015 certified and is a pioneer in the field of electromechanical engineering products, allied equipment, and services. We are a well-established industry leader and authorized Elgi air compressor dealers. Contact us on +919819907445 and we would be happy to help you determine the right air compressor for your needs.