If you’re noticing unusual moisture and condensation in your compressed air system, you may have a lot of questions. Namely, why is it happening, and how can you fix it? If you’re in an environment that demands 100% moisture-free compressed air, you need a solution fast. Excess condensation in an air compressor can also cause significant damage inside the compressor. Learn more about this common concern and what you can do about it.

Why Is There Excess Moisture in My Air Compressor?

Moisture is a natural part of the compression process. Ambient air has some level of moisture in it already, and the compression process extracts it. Mechanically compressing air increases its heat and its pressure. The hotter air is, the more water it can hold. However, highly pressurized air can’t hold as much water vapor, so the excess water turns into condensation inside the system.

Most air compressors include dryers or other components to reduce the condensation. When you notice moisture buildup, it could be caused by:

  • Equipment failure: As its internal parts wear out, an air compressor becomes more prone to moisture. It’s even worse if the system hasn’t been maintained correctly. Over time, the system loses the power and efficiency to extract water. At the same time, the compressor heats up more rapidly, allowing more moisture to build up.
  • Environmental factors: All air has moisture in it, and humid air has considerably more. If your compressor takes in that extra moisture, there will be more condensation within the machine. You can prevent this in several ways. First, move your compressors to a less humid area. If you have conditioned indoor spaces, use your compressors indoors. You can also use a refrigerated air dryer to reduce moisture. If you need a steam-free work environment, you can also use a desiccant air dryer.
  • An undersized unit: If you’re straining your air compressor beyond its capacity, it will heat up more rapidly. This problem is more significant with piston compressors, which generate more heat when used for longer periods. You can combat this issue by investing in a larger air compressor or a separation system. A desiccant separator will remove the water from your compressed air.

What Are the Dangers of Excess Moisture?

Excess air compressor moisture can cause early failure of your compressor or your air-powered equipment. The potential consequences include:

  • Rust and piping corrosion: Water, oxygen and metal components generally don’t mix. When the water builds up inside your air compressor, you can experience rust and corrosion inside the machine and pipes. Water in your air compressor can also cause hammer events, which you can identify by the knocking heard inside the piping.
  • Damage to pneumatic controls: Operations relying on pneumatic controls can’t afford moisture within their air compressors. Water in the compressed air supplied to pneumatic devices can cause rust, scale buildup and clogged orifices.
  • Rapid wear of production equipment: Water can wash away the lubrication inside compressors and air-powered machines. As these oils and lubricants get washed away, metal components begin to wear down prematurely.
  • Damaged circuits and in-line filters: In-line filters clean your compressed air of particulates and oils. Over time, moisture increases the pressure drop across these filters, making them less efficient and costing you money.
  • Contamination: Water can ruin end products, valves, air or motors. For example, if you’re using an air-powered spray painter, water in the compressed air supply will mix with the paint and compromise the job. Water can also compromise pneumatic tools, sandblasters, CNC machining centers, air cylinders, robotics and valves. Anything from solvents and lubricants to food products and finishes will be contaminated by exposure to water.
  • Ice buildup: If moist compressed air is exposed to low temperatures, ice will form. The ice itself can damage equipment or clog air lines.

How to Eliminate Excess Moisture

Wondering how to fix air compressor issues related to condensation? Try these solutions:

1. Install an Internal or External Air Dryer

An air dryer is a separate device that works in conjunction with an air compressor to remove water vapor. You’ll find many types available for different applications. The four most common types of air dryers you can choose from include:


  • Refrigerated dryers: The most used type of air dryer uses dual heat exchangers to cool hot air entering the compressor. Refrigerated dryers have many applications and are cost effective. They dry air to an appropriate level for most air uses.
  • Desiccant dryers:For highly moisture-sensitive environments, you can use a desiccant material, such as silica gel, molecular sieves or activated alumina, to absorb moisture from the air. They are often heatless, and heated versions will purge and regenerate the desiccant material. An oil-free compressor can even use the heat of a compression desiccant dryer, which heats the desiccant using the excess compressor heat.
  • Membrane dryers: Membrane dryers work as dehumidifiers, which lowers the dew point of air entering the compressor. They are as effective as desiccant dryers while requiring less maintenance.
  • Deliquescent dryers: One of the most basic air dryers, a deliquescent dryer, is low-maintenance and uses no electricity. They work using a pressure vessel and a dissolving tablet that absorbs water vapor. These dryers can also dry natural gas and landfill gas.

Your facility may also need a specialty gas and liquid dryer or a breathing air purifier to dry your compressed air. Contact your Fluid Aire Dynamics distributor to find out which compressor is right for your machine.

2. Purchase a Water Trap

One of the simplest ways to filter out air compressor condensation is with a water trap combined with other filters. As the compressor takes in air through the inlet valve, the water trap bowl extracts moisture and sends it into a drain. After the water drains, the air passes through a filter to eliminate other impurities. This system can be an excellent choice for airbrushes and sanding tools, which require extremely dry air.

3. Use a Piping System

The most cost-efficient solution to moisture buildup is a piping system. In this configuration, tall, vertical metal pipes absorb heat to lower the air temperature. The water can then drop down to the bottom of the pipe, where it can be contained at drip legs within the piping. They’re an excellent option for office buildings and independent craftspeople powering air tools.

Why Preventive Care Is Key

The best way to fix air compressor issues, including moisture buildup, is with preventive care. If you wait until a failure occurs, repairs inevitably cost more. They also create unscheduled downtime, which costs you even more. Scheduling regular maintenance lets you catch issues early before they become more prominent, costlier concerns. The right air drying solution is crucial to adequate preventive care.

Fluid Aire Dynamics’s preventive maintenance program allows you to schedule maintenance at regular intervals. Working with us to build a compressor service schedule can reduce your downtime. Our team of maintenance professionals can catch worn down parts before they cause moisture buildup. While on a site visit, they can identify humidity levels at your facility and make recommendations to prevent moisture concerns. If you have an undersized compressor unit, they can determine the best way to correct it, whether with a larger machine or an air dryer.

Contact Us to Evaluate Your Air Compressor System

Moisture creates poor quality compressed air, causes equipment damage and may even compromise your operations and final product. Fluid Aire Dynamics has a full line of air dryers and accessories from top manufacturers to help you mitigate this issue. We’re also committed to helping you get the most out of your air compressors and other investments. That’s why we offer a Free Compressed Air System Review to find the root cause of your moisture buildup and recommend the correct solutions. Fill out our online contact form to learn more about our compressed air products and services.