Comparing an Oil Lubricated and Oil Free Air Compressor

March 26, 2024

Comparing the two solutions for performance, efficiency, savings, and quality

A visual comparison between two types of air compressors: lubricated and oil-free. On the left, a smaller, lighter lubricated air compressor is depicted within a blue circle, labeled as such. In the middle, a large “Vs” indicates a comparison. On the right, a larger, darker oil-free air compressor is shown, also within a blue circle, with the label “Oil-free air compressor” below it. The background color outside of both circles is light blue.

Oil vs oil free compressor

Deciding between a lubricated compressor with additional air purity accessories and an oil free air compressor is important to ensure high-quality compressed air in your operations. Here are five key considerations when determining the best fit for your business.

Contamination risks
Power and output
Reliability
Maintenance
Investment: Short-term vs medium-term value

1. Contamination Risks

Oil-injected compressors need additional accessories like filters (air/oil separator, coalescing filters and activated carbon filtration) to mitigate oil contamination risks. Oil-free compressors on the other hand fully eliminate any contact with oil during the compression process. By preventing oil from mixing with air, you completely remove the risk of contamination. This means you don't have to use multiple filtration steps to reduce the risk.

Oil is not mixing with air. No oil is getting into the compressed air line and no oil contamination in the water. This eliminates the need for condensate water treatment.

Our oil-free compressors offer certified Class Zero Air, according to ISO 8573-1. Even with the best filters, you can't get 'Class Zero' air qualtiy using oil-injected compressors.

2. Power and output

Oil-free air compressors require less air filtration, saving energy by not having to work against multiple filters. This means there is less pressure loss in the line. Oil free air compressors can run at a lower pressure, saving energy and ensuring clean air.

Lowering the compressor pressure setting by one bar for medium pressure air can save about 7% energy. Lowering the pressure setting reduces air leaks and improves the efficiency of the compressor installation.

3. Reliability

Adding more accessories creates more responsibility. When using accessories with lubricated compressors, be cautious of their potential for low reliability. For instance, activated carbon filters typically last longer when used with air temperatures between 30-35°C. However, if the temperature rises, the filter's lifespan decreases significantly.

Invest in good products to ensure quality. Keep in mind that opting for cheaper options may lead to additional purchases and risk in the long run.

4. Maintenance

Oil-free air compressors do no use oil during compression. This means they require fewer spare parts and have more uptime. As a result, there are fewer maintenance interruptions. Lubricated compressors need more regular maintenance, oil change over and careful filter changes to reduce oil contamination risk.

5: Investment: Short-term vs medium-term value

The financial aspect is a critical factor in the purchasing decision. You must carefully consider the cost-benefit and investment value.

Lubricated compressors are more cost-effective, addressing immediate business needs. Oil free air compressors are a better choice in the long run if air quality is paramount. They have lower maintenance costs and are more reliable. Although they may cost more upfront, they provide a safer and more economical option over time.

How does an oil lubricated air compressor work?

Oil lubricated compressors use a specialised oil to lubricate the compressor screws. The screw elements in the compressor are essential for compressing air.

During this process, oil and oil vapor naturally mix with the air. The oil lubricates the compressor and helps cool it. It also seals the screw elements to prevent air from flowing back.

How does an oil free air compressor work?

Oil-free air compressors don't need oil to lubricate or cool the compression elements. They have a special design that eliminates the need for oil in this process.

To achieve this goal, we are using different technologies. For medium pressure air applications (up to aroung 10barg) the most common technologies are scroll elements (low flows only), oil free twin screw elements (low to high flows), and turbon Tcompressors (higher flows). Oil-free pirstons are being used for high pressure applications.

Are you interested in learning how an oil free air compressor can enhance your production? Contact us now to talk to our experts about how an oil-free air compressor can boost your production and performance.