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What Is Dew Point?

When using air compressors, there are many variables that are integral to the quality and effectiveness of your compressed air. When dryer air is necessary, being able to constantly and accurately monitor dew points can be a critical factor to your operation.

Dewpoint is the temperature at which water vapor in your compressed air is no longer vapor, and changes to a liquid form (condensation). As your compressor is compressing air, the stored air can become very warm, meaning that it contains a lot of water vapor. As the air cools down, that vapor will turn to condensation. If enough condensation forms, you now have free-flowing water through your air lines. Having water in your compressed air is never a good thing, and depending on the application, it can become catastrophic.

Large amounts of water in your compressor and/or compressor air lines can cause bacteria or mold to form, as well as pushing moisture into your compressed air. This renders the compressed air useless in most applications. Food & beverage companies cannot use this air to package or enhance food products. Pharmaceutical or medical companies cannot use contaminated air or humid air in hospitals or for any medicinal applications. Body shops can’t use air that contains water to paint vehicles because it ruins the final product. Because condensation typically ruins compressed air for most applications, it is important to make sure you monitor your unit’s dew point as it is in operation.

How Do I Prevent My Compressed Air From Reaching its’ Dew Point?

In order to monitor your compressor’s dew point and keep the air dry, an air dryer is often used for most compressed air applications. Dryers can be integrated (built-in) to the compressor, or they can be standalone units. Air dryers will lower the dew point of your compressed air, making it more difficult for the air to condense vapor into water. This keeps your air dry and your piping and hoses free of any moisture and potential for bacteria.

For most compressed air applications, monitoring the dew point and making sure your compressed air doesn’t reach its’ dew point is critical to keeping your business running efficiently and effectively. Dryers are essential in keeping your compressed air cool and free of moisture and contaminants. To learn more about our dryers, click HERE.

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Who we are and how Ash Air can help your business!

Ash Air has been around in New Zealand since 1979, and we’ve grown into a nationwide company with international support and a reputation for quality and reliability.We look after all things compressed air for your business!

  • Reciprocating, Screw, air compressors
  • Vacuum pumps
  • Nitrogen
  • An extensive line of air treatment components

Ash Air's range of Chicago Pneumatic, Alup, Pneumatech, and Quincy compressors are used extensively around the world in industries ranging from oil and gas to food, automotive and farming, and we bring you these world class compressors here in the land of the long white cloud.Our technicians are compressed air equipment experts and are dedicated to addressing customer needs. Supported by a 13 locations nationwide, Ash Air offers one of the widest selections of compressed air equipment and parts available today in New Zealand.

Reliability and Efficiency

With Ash Air compressors, you can count on reliability and high performance for even the most demanding applications. We focus our efforts on the following:

  • Increasing uptime
  • Reducing unexpected repairs
  • Reducing energy consumption
  • Improving the cleanliness of compressed air


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Read more from our #expertcorner


Just like any other equipment, a compressed air installation also requires the necessary maintenance work during its entire lifespan. Even though maintenance costs are only about 5 to 10% of a machine's annual operating costs, failure to budget for maintenance can have potentially disastrous consequences.


The air dyer is one of the most ignored cooler in the system. A dirty condenser will cause water in the lines, or worse it will cause complete dryer failure.