Air Supply UK: Specialist Compressed Air Engineers

Published: 17/02/2022

A guide to choosing the best oil free air compressor

Oil free air compressors, or oilless air compressors, are now widely used in factories, workshops and industrial applications. These compressors are used when the risk of oil contamination from an oil lubricated air compressor can be dangerous or where a certain level of air quality is required. 

Choosing the right oil free air compressor for your needs can be difficult so we have compiled this complete guide to oil free air compressors, including the factors to consider when buying one for your application. 

How do oil free air compressors work? 

The first step to understanding whether an oil free air compressor is right for your application is understanding how they work. 

For an oil lubricated air compressor, the oil is designed to reduce friction between the moving parts of the compressor which can improve efficiency, reduce maintenance costs and provide safety in environments where high temperatures can cause a risk of explosion. 

One of the biggest disadvantages of an oil lubricated air compressor is the air produced is contaminated which makes the compressors unsuitable for use in some applications, such as food and beverage production. 

In contrast, oil free air compressors do not contain oil. Water or a teflon coating is used to protect the pump and allows the moving parts of the compressor to work without the need for any oil-based lubrication. 

Oil free air compressors provide a solution for compressed air applications where air purity is a necessity. 

Different types of oilless compressors are available including: 

  • Oil free rotary screw air compressor 
  • Oil free piston compressor 
  • Oil free scroll compressor 
  • Oil free rotary lobe compressor 

Find out more about what oil free air compressors are and how they work by reading our guide. 

Pros and cons of an oil free air compressor 

When it comes to choosing an oil free air compressor for your application, it’s important to consider the pros and cons. This will help you to decide whether this is the right type of compressor for your intended use. Pros of oil free air compressors 

The main benefits of oil free air compressors include: 

  • Less maintenance – oil lubricated air compressors require regular maintenance to top up the oil levels and ensure the mechanism inside is able to function correctly. The lack of oil in an oil free air compressor can make it a more cost-effective option over the long-term. 
  • Lighter – these types of compressor have fewer parts inside which means they weigh less than oil lubricated compressors, making them more suitable for portable applications. 
  • Reduced operating costs – oil free air compressors do not require replacement or repair as often as other types of compressor due to fewer working parts inside which means they do not cost as much to operate.
  • Reduced risk of contamination – a lack of oil within the compressor means there is no risk of air contamination and prevents product recalls and unnecessary downtime for businesses when products or the air stream becomes contaminated. A lack of contamination can also protect equipment and lead to lower maintenance and replacement costs. 

Cons of oil free air compressors 

It’s also important to consider the cons of oil free air compressors to find the right machinery for your application:

  • Lower lifespan – oil free air compressors are cheaper to buy initially than their alternatives but they tend to have a lower lifespan due to the lack of oil inside. The Teflon coating can be worn down and the parts inside become vulnerable to damage from friction. 
  • Noise – one of the biggest disadvantages of oil free air compressors is the noise they produce due to the parts inside that rub together. Modern compressors use technology such as sound dampening and soundproofing to prevent these problems. 

To find out more about the pros and cons of oil free air compressors, including the industries they’re most suited to, please read our guide. 

Oil vs oil free air compressors 

Both oil and oil free compressors perform the same function but the way they work, the way they’re made and the applications they can be used for are different. 

How do oil free air compressors work? 

As we have already mentioned, oil free air compressors have no oil within the compression chamber. The parts inside the compressor are coated with permanent lubrication which helps to protect the piston parts when the compressor is in operation. 

How do oil lubricated air compressors work? 

These air compressors use oil to protect the moving parts inside the compressor. This lubrication helps to keep the compressor functioning properly and helps to maintain the lifespan of the compressor. 

When choosing between an oil free or an oil lubricated air compressor, there are a few key factors to consider:

  • Maintenance – oil based air compressors require more maintenance as the oil will need to be changed on a regular basis to ensure the compressor continues to function properly and efficiently. 
  • Air contamination – when using an oil lubricated compressor, the air can be contaminated with traces of oil. For many applications, this is not a problem but high air purity is required in food production, medicine, electronics and sensitive products so an oil free air compressor will be essential. 
  • Durability – oil based air compressors tend to have a longer life expectancy because the oil means that less wear and tear takes place inside the compressor. As a result, they are more suited to commercial applications where the compressor is heavily used. 
  • Cost – oil based air compressors carry a much higher initial cost than oil free air compressors but they also offer a much longer lifespan and a larger capacity. Oil free air compressors have a lower initial cost and ongoing costs but have a much lower lifespan. 

For more information on the differences between oil and oil free air compressors, take a look at our full guide. 

Maintaining an oil free air compressor 

Oil free air compressors require minimal maintenance but it’s important to make sure they remain safe and efficient throughout their lifespan. 

Regular maintenance will keep your air compressor in the best condition for as long as possible and to save costs on replacement. Within sectors where the risk of air contamination must be avoided, maintenance is even more important to make sure that machinery continues to run as it should. 

Here are some of the steps you can take to keep your oil free air compressor in the best working order: 

  • Drain the compressor tank – failing to do this can damage the compressor and cause it to stop working.
  • Inspect the power lead – check for wear and tear and call an electrician if you notice any damage.
  • Check pressure – high pressure can damage the compressor over time. 
  • Check behaviour – irregular behaviour can be a sign of a fault and a sign that maintenance checks are required. 
  • Check air filter – air filters vary by model but a paper or felt filter will require replacement and a foam filter will need to be cleaned. Keeping the filter clean will help to keep the compressor running properly and efficiently. 
  • Check seals – seals can experience wear and tear and will need to be replaced eventually. It’s better to replace the seals when you notice wear and tear instead of once they have deteriorated to the point that the compressor can no longer function correctly. 

Read our full guide on oil free air compressor maintenance to find out more about keeping your compressor in full working order throughout its lifetime.  

Choosing the best oil free air compressor 

Once you know what an oil free air compressor is, how it works and the pros and cons, you should be able to determine whether or not it is right for your application. Here’s a quick guide on the factors you should consider when choosing an oil free air compressor and our top-selling oil free air compressors. 

Factors to consider 

1. Application 

Buying any air compressor is a significant investment so it’s important to consider the application of your air compressor and choose the right machine for the job. 

Understanding the following factors will help you to determine how the compressor will be used and which type may be most suitable: 

  • Business needs for the compressor 
  • Demand 
  • Types of tools you’ll be using 
  • The kind of power required 
  • Maximum level of air pressure required 

All of these factors can have an impact on the type and size of air compressor you need. 

2. Does the air need to be contaminant free? 

If you need contaminant free air, an oil free air compressor will be required but, while the air will not be contaminated by oil, there may be other contaminants involved. Every industry and application will have different requirements from an oil free air compressor so it’s important to speak to the company you’re buying the compressor for for advice if required. This will help you to make sure you choose the right oil free compressor for your application. 

At Air Supply, we have been providing air compressors for the last 25 years so we have an expert team who can provide advice and guidance to make sure the right compressor is specified for the job. Contact our team for more advice. 

Considering these factors will ensure that you choose the correct air compressor for your business and make sure it lasts for as long as possible. 

If you’d like to know more about oil free air compressors, please contact our team today. 


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