Why air dryers affect end product quality and your maintenance cost

Including an air dryer in your compressed air system might not seem like a priority or even necessary. Compressed air is what you need to run your application and surely the majority of the free water is removed via the aftercooler anyway, so, why bother with compressor dryers?

If the quality of your product and process matters, then the quality of your compressed air matters too.

FD1750 VSD+ air compressor dryer

Air dryers improve the quality of compressed air

The air around us contains microscopic dirt particles and water vapour and, when we compress air, we also heat the air up, which allows even more water vapour to exist in the air. This can add up to a lot of extra water in the system – and in your products.

The average rotary screw air compressor is usually fitted with an aftercooler, which will succeed in removing between 75-80% of the free water in your process air, and also cool it down to 10-15°C above ambient temperature. That, however, does not suffice for the high quality air required in many manufacturing and process applications.

As the air in your compressed air system begins to cool down after it has left the compressor, the water vapour in the air begins to condense into water droplets. You won’t need to consult an expert to know that water running in your compressed air pipes poses a corrosion, contamination and possibly even a freezing risk and could damage your air tools. So what can you do to protect your machinery and end product?

Adding a compressed air dryer to your system is straightforward and economical

Compressor with integrated dryer

Atlas Copco Full-Feature air compressor with dryer integrated

Atlas Copco and other manufacturers offer a range of compressed air dryers, all tailored for particular applications to ensure that the air you get is as dry as you need it. Some compressor manufacturers offer “full feature” compressors, which contain integrated refrigerant air dryers inside the compressor canopy, saving on space, installation cost and lifecycle service costs. This way, you further mitigate the risk of free water and corrosion in your air distribution system and take one more step towards achieving certain ISO quality standards.

As a rule of thumb, a refrigerant dryer is suitable for most industrial applications since it lowers the pressure dewpoint (commonly referred to as PDP, which is the point where you would begin to see condensation forming) of your compressed air to +3°C. That means you would not have to worry about condensation unless your pipework is exposed to freezing temperatures.

CD desiccant dryer by Atlas Copco allows you to reach dewpoints as low as -70C

Desiccant air dryers can give you a dewpoint as low as -70°C

Some applications, however, require air with a much lower dewpoint, in which case you would need to look at desiccant air dryer technology, which can give you a dewpoint as low as -70°C.


We recommend referring to the ISO 8573-1:2010 standard when specifying new air compressor installations and when reviewing your air system, but if you are stuck for ideas, our air experts are always happy to answer your questions.

Explore the whole range of Atlas Copco compressed air dryers and their applications.

Do you know how much water vapour is in your air system right now? Try our calculator to find out.


Would you like to know how an air dryer works or what methods of air drying there are? Download our compressed air dryer whitepaper to read more.

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2017 Compressed Air United Kingdom Energy Efficiency Aftercoolers Air dryers Desiccant air dryers