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Rotary Screw Air Compressor Buying Guide

Air Compressor Dryer Installation Diagram

Rotary Screw Air Compressor Buying Guide

This rotary screw air compressor buyers’ guide is all about a workhorse of various industrial applications; the rotary screw air compressor. A rotary air compressor can guarantee 24 hours of air supply if there is a need to. In this buying guide, you will learn everything you need to know when buying a rotary screw air compressor. If you are not sure if a rotary air compressor is the right one for you, then you should stay ion this page to find out more.

Buying a rotary screw air compressor

Air Compressor Dryer Installation Diagram

Do you want to be sure you are making the right decision in buying a rotary screw air compressor?Do not worry. You are in the right place.

In this rotary screw air compressor buying guide, you will learn:

  • Who should buy a rotary air compressor, and who should stay away from a rotary screw air compressor?
  • What is the right size of a rotary air compressor for you?
  • How to save money when buying a rotary air compressor.
  • Which options should work for you?
  • Most common mistakes people make when buying a rotary screw compressor


Who needs a rotary air compressor?

Rotary screw air compressors are perfect for the following group of people and applications:

  • Large garages and workshops with air tools
  • People who require a lot of compressed air.
  • Large or small production facilities or industries

But there are many situations where various businesses opt for rotary screw air compressors in places where reciprocating air compressors can work better. If any of the following applies to your projects, then you do not need a rotary screw air compressor:

  • You need air compressors for hand tools.
  • You do not need air continuously.
  • You only need compressed air for home DIY work.
  • You need compressed air for light construction works, such as powering nailers.

In the above cases, you can go for a reciprocating air compressor to get the work done in the best of ways.

Choosing the right capacity and pressure for a new rotary screw air compressor.

It is essential to consider the right air compressor that can supply enough amount of compressed air at the right pressure to power all your tools. Unfortunately, most people do not know their requirements and end up buying too big or too small air compressors.

So, this section will help you in that respect. If you opt to buy a rotary screw air compressor, it should be for the following reasons.

1. It is your first air compressor

Check your user manual and specification sheets of the pneumatic equipment. This part should tell you the right pressure at which your air tools operate and the capacity you need. The components that require the highest pressure will dictate the pressure requirement. You should also add 1.5 bar to the minimum pressure required to account for any pressure drop and load-unload differential of your rotary air compressor.

After that, you should add up the air consumption of all your air tools. This should be the capacity of your air compressor. It is essential to buy a bigger air compressor, but not too big. Rotary screw air compressors do not like standing still. You should keep in mind that some air tools come with average consumption rating while others state the maximum consumption rating.

2. It is a replacement for an old rotary air compressor.

You should check the capacity and pressure of your old rotary air compressor.If the old air compressor you had was adequate, you should buy a new air compressor of the same pressure and capacity. You should take a moment to decide whether it is the right choice to get a slightly bigger air compressor to account for future consumptions.

3. You have a reciprocating air compressor and need more capacity (cfm).

You should check the pressure of the current air compressor. Ignore the maximum pressure rating of a reciprocating air compressor since it is often higher than what is needed to operate your air tools.

If you want a replacement for your air compressor, you should check the capacity of the current air compressor. Now you understand that you should buy a slightly bigger air compressor than the current one. How big? This one depends on the type of air tool and equipment you added to the business that made you opt to get another air compressor. You should also keep in mind that your business can expand in the future.

If you want a replacement to your old air compressor, you should keep in mind that a rotary screw air compressor does not like standing still as it will likely be old and rusty. In this case, you have to ensure that your rotary air compressor is the primary compressor, while your reciprocating air compressor becomes the secondary compressor. Rotary screw air compressors are the most energy-efficient.

4. You have a rotary screw air compressor and need more capacity.

Most of the time, people tend to buy the same type of air compressor as the one they already have. This is an excellent idea because it allows you to use the two air compressors side by side or use one as a backup for the other. Another great idea is buying a slightly bigger air compressor and use the old one as an emergency back up option.

Small air compressor oil change

Rotary screw compressors come in a wide variety, with various options and specifications. But what is it that you need? What extra features would work for you? Take a look at some of the things you may want in a rotary air compressor.

Integrated air dryers and filters

Various rotary screw air compressor manufacturers offer all-in-one solutions for your needs. This means that you can have an air compressor that comes with an integrated compressed air dryer and compressed air filters. For almost every system, it is recommended to have an air compressor with a compressed air dryer. The same applies to compressed air filters. Since compressed air is often wet and dirty, these aspects help in saving your equipment from premature failures.

It is crucial to keep in mind that compressed air dryers and filters create and add to pressure drop in the air compressor system. With this in mind, you should understand that you will incur the extra cost of energy for you to overcome the pressure drop.

Electronic condensate traps

Do you really need this one? The answer is not necessarily. But is it better? Yes. The number one maintenance issue with an air compressor is often a dirty, clogged, and non-functional condensate trap (the mechanical one with floater). Such a condensate trap will make your compressed air system have a lot of moisture.

However, it is easier to discover when your condensate trap is non-functioning if you keep draining or checking the drain on your air receiver frequently and manually. But what if you are the type that does not like frequent manual checking? That is where an electronic condensate drain comes in handy. An electric condensate drain can be installed afterward if you do not want to spend money on it at the moment.

Variable speed drive (VSD)

A variable speed drive compressors one that automatically matches the output capacity to the demand of your air tools. In other words, it regulates the sped of the compressor, depending on the pressure level.

A VSD air compressor is the right one to save energy. This might be true to some extent, but not always. Additionally, a VSD air compressor may not be an excellent choice for you if:

The air compressor runs between 90% and 100% speed all the time. A variable speed drive air compressor that runs at full speed consumes more energy than a standard fixed-speed air compressor.

The air compressor runs between 10% and 20% all the time. This type of air compressor is too big. The best alternative is getting a smaller fixed-speed air compressor that is more energy-efficient. Furthermore, air compressors that run at such low speed have frequent maintenance issues.

A variable speed drive air compressor is an excellent choice if it runs between 50% and 80% load. This range is where energy efficiency lies. Additionally, it allows the air compressor to heat up, which prevents a lot of maintenance issues.

Belt drive or direct drive

A direct drive air compressor is the best. However, belt drive units are more compact, but they are noisy and may require added maintenance, especially if you are working in a dusty environment.


One of the most standard specifications of a stationary screw air compressor is an aftercooler. This feature is essential in many ways. Without the aftercooler, the compressed air that is produced by your compressor will be around 80-100 degrees, which is too hot to go into the air dryer, or any other air tool.

Apart from that, the aftercooler removes moisture from the compressed air. If your air compressor does not have an aftercooler, all that moisture stays in the compressed air and condenses when it cools.

Energy efficiency

Most people buying an air compressor fail to realize that the purchase is just the beginning of the task. Over the entire lifespan of the air compressor, the cost of the initial purchase is only 10%, the maintenance accounts for about 15%, while the remaining 75% goes into energy consumption.

What is the Difference Between Piston and Rotary

If you ever find yourself in a position to choose from two comparable air compressors, always go for the most energy-efficient one. This decision will save you a fortune in energy costs. Even if the most energy-efficient air compressor is more expensive, it is still preferable in the long run.

The benefits of using a rotary air compressor

There are very many types, models, and sizes of air compressors, but none can be compared to a rotary air compressor in terms of performance. It can be said that a rotary screw air compressor is designed to work flawlessly and continuously all year long for very many years. So, what makes a rotary air compressor that efficient? The following reasons do:

Energy savings

One of the main reasons why rotary screw air compressors are most preferred is the fact that it is one of the most energy-efficient air compressors. As mentioned earlier, the upfront cost of a rotary screw air compressor may be a bit high. Still, the overall cost, which includes maintenance and energy consumption, is often lower compared to other air compressors.

Durability and strength

Within the range of all air compressors, a rotary screw air compressor is considered to be the most durable and super reliable, which makes it capable of running continuously for years. This makes rotary screw air compressors the most long-lasting of them all and, therefore, suitable for all industrial applications.

Guarantees clean and fresh air

A rotary screw air compressor is among the few air equipment that produces clean air. The excellent design and mechanism of the air compressor enable it to work optimally most cleanly and efficiently. The process of regulating the dew point may be a bit complex to understand, but a rotary air compressor comes with a smart design that keeps oil and moisture in check.

The bottom line

Along with all the advantages of buying a rotary screw air compressor, you can be sure that it guarantees optimal performance when matched well with the requirements of your air tools. If you are convinced enough about the benefits of having a rotary air compressor, then you should find a way of getting one for your compressed air needs.

Buying an air compressor is a different task altogether. You have to take your time and consider various factors that we have talked about in this post. What are your compressed air requirements? How big should you go for? Which specifications are best for your sir equipment? If you can answer all these questions, then you are good to go.

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  • Shandong Sollant Machinery Manufacturing Co., Ltd.

    12 years of professional export experience. Our twin-screw air compressor is very popular in the international market.

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