Air dryers: FAQs

Air dryers: Isn't air dry?

Air has moisture and water vapor in it. When your air compressor compresses this air, the air – and the moisture – are heated. As it cools, the air has less ability to hold this moisture. Eventually, the air reaches a ‘dew point’. This is the temperature where the water vapor condenses into droplets. Known as condensation, these droplets are basically just water, but still have the potential to cause great damage as they flow through your compressed air line, machines and tools. 

Air dryers: Do you need one?

We recommend using an air dryer to remove condensation and moisture from your compressed air. Why? The condensation will result in: 

• extra maintenance and downtime;

• a greater likelihood of corrosion and rust in boilers and piping;

• oil and lubricants in pneumatic tools and cylinders becoming contaminated and even washed out;

• blasting materials like sand clumping together;

• a kind of fogginess on surfaces you spray with compressed air.

A compressed air dryer removes the unwanted condensed water. The result? Dry air. No condensation. Less downtime. And one less worry to keep you awake at night.

What types of air dryers are there?

The most common type of air dryers are cooling air dryers and adsorption air dryers

How do cooling air dryers work?

Cooling air dryers, also known as refrigerated compressed air-dryers, circulate a cooling gas around your system, dropping temperatures to 3ºC or lower. This causes condensation; the dryers then remove it from the air before causes any damage. The process may sound familiar: it’s what domestic air conditioners do.

Worried about the effects of these cooling gases on the environment? Good news: Our ALUP dryers use R134a, R410A or R45A cooling gases. They have no influence on the ozone layer and less environmental impact than any other cooling gases. 

How do adsorption air dryers work?

Adsorption dryers are also known as desiccant dryers and ‘getters’. They blast moist air over hygroscopic material that removes the moisture from the compressed air. An obvious question: What’s hygroscopic material? The answer: Any material, whether it’s a solid or a liquid, that attracts moisture to it. This material will ‘get’ and hold the moisture. (Now you see why they’re known as ‘getters’.) However, this material needs to be replaced; otherwise, it will become saturated and stop removing moisture from the air. For this reason, adsorption dryers are usually used after a cooling air dryer when most of the moisture has already been removed. 

Adsorption dryers easily reach temperatures below 0ºC. In fact, they’ll reach dew points of -20ºC, -40ºC or -70ºC. Cool, huh?

Which compressed air dryer should you choose?

The choice of a compressed air dryer depends on what you’re using the compressed air for. There are often regulations involved (such as BRC, BCAS, IFS and Pharmacopoeia to name a few).

A cooling dryer is the most commonly used dryer for compressed air. By cooling the temperature to around 3ºC, most of the moisture condenses and is removed, leaving the compressed air suitable for 90% of applications. ISO 8573-1: 2010 purity class 4 is met by using a cooling dryer.

However, an adsorption dryer is a must if you need to reach a lower dew point. Adsorption dryers have pressure dew points of -20ºC, -40ºC and -70ºC. Adsorption drying is often used in the food, pharmaceutical, medical and chemical sectors.


Browse Ash Air's range of air dryers here

Refrigerated Dryers

Ash Air has a range of quality cycling and non-cycling Pneumatech refrigerated dryers for your air compressors.Our non-cycling Pneumatech refrigerated dryers offer a reliable and economic solution for removing moisture from your compressed air system. These refrigerated dryers for air compressors are easy to install, offer energy savings, prevent pressure losses, are equipped with rotary compressors and R410A refrigerant, and have improved connectivity features.

The Ash Air collection of very dependable cycling Pneumatech refrigerated dryers offer easy-to-use controllers, are easy to install with low maintenance needs, and are energy efficient with zero-loss drains.

We also supply a range of superior performance refrigerated dryers for air compressors with variable speed technology that matches energy consumption to the actual compressed air demand, have stable pressure dew points, and are available with both air-cooled and water-cooled condensers.

Desiccant Dryers

Our innovative desiccant dryers give customers efficient protection against the presence of any humidity in the air, which often is the source of pipe corrosion and decreased efficiency of equipment and tools.

The Ash Air range of advanced technology 360-1080 m3/hr and 1188-10800 m3/hr adsorption air dryers are for customers who have a focus on energy efficiency and low operating costs, while maintaining the highest standards in air purity. Our Pneumatech blower purge air dryers use heated blower purge air to remove moisture from the desiccant material, which means no purge loss during regeneration.

Breathing Air Dryers

Here at Ash Air, we offer BA 15-310 HE Breathing Air Purifiers. The Pneumatech solution for Industrial Breathing Air applications, build to exceed standards. The Breathing Air Dryer range assures safe working environment in a wide range of applications. Built to exceed standards, Breathing Air Dryers provide certified breathing air, even in situations with polluted intake air to ensure personnel safety at all times.

The Pneumatech solution for Industrial Breathing Air applications, build to exceed standards. The Breathing Air Dryer range assures safe working environment in a wide range of applications. Built to exceed standards, Breathing Air Dryers provide certified breathing air, even in situations with polluted intake air to ensure personnel safety at all times.



Do you have an idea for our #expertcornerLet us know!

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!

  • Rotary Screw and Piston Air Compressors
  • Vacuum Pumps and Blowers
  • Nitrogen Generation
  • An extensive line of Air Treatment components
  • AIRnet Piping System and  Filtration
  • Mobile Compressors, Generators, and Light Towers

Ash Air's range of Chicago Pneumatic, ALUP, Pneumatech, and Atlas Copco products 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 with nationwide coverage, Ash Air offers one of the widest selections of compressed air, vacuum pump, and industrial gas equipment and parts available today in New Zealand.

Reliability and Efficiency

With Ash Air, 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 and meeting our sustainability goals
  • Improving the cleanliness of compressed air


Talk to the team today:  CONTACT US CONTACT US

Read more from our #expertcorner


We get it, buying an air compressor is a big financial decision. And now we are suggesting that you need two air compressors, not just one. Ask yourself one question- Can your business still run if your air compressor goes down?


It’s no secret – air compressors are excellent sources of energy. Not only do they power essential manufacturing elements and applications, but the heat generated as a result of the compressed air processes can be used as a byproduct that offsets other energy costs. However, there’s another form of energy that is also a consequence of the air compression process – sound.