When Do Air Compressors Need Filters?

Seventy percent of all manufacturers use some type of compressed air system. Air compressors produce tighter, and more pressurized air to generate a steady stream of airflow. This airflow is then used to power a variety of tools, assembly lines, and pneumatic equipment.

Compressed air is crucial to many industrial and manufacturing processes. If contaminated, this compressed air can result in product spoilage, reduced performance, and damaged equipment. All of these can lead to unexpected costs and downtime for manufacturers.

Industrial compressed air systems rely on proper filtration to ensure air purity and reliability. Choosing the right air filter will not only boost the efficiency of your compressor and produce safe airflow, but also reduce energy costs and protect workers from dangerous particulates and contaminants. 

Air compressor filters are available in a wide range of sizes and configurations, but they’re all designed to capture contaminants and ensure the resulting compressed air is as clean as possible. The type of filter you will use will depend on some factors, such as the conditions of your workplace, how often you use the compressor, and the specific project you’re completing. 

In this guide, we will detail the different types of air compressor filters, how they work, why they’re necessary, and how often they should be replaced.

Why do you need an air compressor filter?

Every cubic foot of air that enters your compressor can contain millions of impurities. These foreign particles can accumulate, causing premature wear to your compressor and control valves, swelling in protective seals, and health risks for your employees.

Below are common particles that may contaminate pressurized air. Knowing the types of contaminants you need to eliminate can help you select the right filter for your compressor.

Oil and lubricant

The amount of oil particles that may pass through pressurized air depends on the design, type, operational age, and overall condition of your compressor.

Oil-lubricated air compressors require adding and changing the oil regularly. As a result, air can enter the compression process and airflow, affecting pneumatic tools and overall output. To prevent filling the compressor body with oil, specialized filters and automated shut-off valves are used to prevent oil from passing through the main injection ports.

Water vapor

High humidity in workspaces and other gasses produced during the compression process can form water vapor particles. Continued exposure to water vapor may shorten the compressor’s lifespan and result in costly repair and maintenance expenses.

The presence of water vapor can also lead to increased leakage, rusting, and corrosion in piping, higher rejection rates for plastic injection and spray painting, and control system inefficiencies.


When impurities in the compressed air mix with oil and water residues, microorganisms might develop and grow in piping networks. This can then lead to viruses and bacteria further contaminating the air coming from your compressor.

Dirt and dust particles

The type of particles that travel through your air-compressed system often depends on your industry or the location of the facility. For example, sites that house a lot of chemicals or construction materials can expose compressed air to dust, debris, and other substances.

Fortunately, all of these contaminants are removable if you have the appropriate filters. Implementing the right filtration system for protection and purification can help limit system downtime, repair costs, and energy use.

Some air compressors require you to adhere to OSHA-approved air quality standards and other government regulations. Specific types of filters can help keep your compressed air system compliant.

Types of air compressor filters

The three basic filters used in air compressors include oil filters, air inlet filters, and air-oil separators.

Oil filter

Clean oil is necessary to ensure the safe operation of the main engine. Oil filters are typically used on larger compressors like oil-injected screw compressors. They ensure that the special oil entering your compressor is free of sand, pieces of rust, and other particles. Inside an oil filter is a paper filter element which is folded to maximize surface area and oil flow.

Air inlet filter

When oil filters become clogged with debris, contaminants may be able to pass through and pollute the air. Oil filters also feature an internal by-pass valve. When the filter’s pressure difference exceeds normal standards, the by-pass valve opens, transferring unfiltered oil into the system.

Air inlet filters keep your compressor in optimal condition by preventing large dust, oil, and dirt particles from entering the system.

Air-oil separator

The air-oil separator is a filter-like component that separates oil from the air that needs to exit the compressor.

During compression, oil is added to seal, lubricate, and absorb the heat. The result is a mixture of oil and compressed air. An air-oil separator ensures oil stays inside the compressor to lubricate the system while oil-free compressed air leaves the compressor and reaches the appropriate pneumatic devices. 

How often should air compressor filters be replaced?

Replacing air filters regularly will prevent premature wear on your compressor and keep oil and air from becoming contaminated.

Generally, compressor filters are replaced twice a year. However, we recommend replacing it as soon as oil filters get visibly dirty or clogged with an oily residue. As dirt and dust collect in the filters, impurities can quickly enter the system and degrade the quality of compressed air.

Dirty air filters may cause premature wear to the valves, compressor element, and any moving parts. As a result, the compressor may be forced to exert more energy just to accomplish basic functions, resulting in greater energy consumption, downtime, and maintenance costs.

An air compressor is a significant investment for any business. Keeping filters in top condition is one way to protect your investment and extend its service life. You may also refer to your compressor’s warranty for air filter maintenance and replacement instructions.

It’s important to note that not all air compressor filters are the same. Some filters clog faster than others and therefore, need more frequent inspections and replacements.

JHFOSTER has certified specialists and technicians who can help you replace your air filters quickly and efficiently. We work with all types of compressed air systems and their components, so you can trust us to meet all of your compressor requirements.

Contact us now for assistance.