Cycling vs. Non-Cycling vs. VSD Refrigerated Air Dryers

The world of air dryers for compressor systems can be difficult to grasp. There are so many options to choose from between cost, type, and brand alone. It can be tough to choose between cycling, non-cycling, and VSD refrigerated air dryers.

Cycling air dryers cycle on and off when needed as they detect moisture in your air compressor. Non-cycling air dryers run constantly which can be quite expensive, but it can also ensure a consistent dew point. Variable speed dryers (VSD) are types of cycling dryers that use frequencies to cycle on and off as needed instead of running constantly.

Avoid a non-cycling refrigerated air dryer if you want to save money on energy bills. You can save over $3,000 in bills with a cycling or VSD dryer compared to a non-cycling refrigerated air dryer. Follow along as we compare cycling, non-cycling, and VSD refrigerated air dryers to see which is best for you.

Do You Need a Dryer for an Air Compressor?

You need a dryer for your air compressor if you use it frequently or professionally. Dryers reduce the humidity within a compressor, and that protects all the metal components within the unit. You won’t have to worry nearly as much about rust and corrosion.

Rust and corrosion can take years off the lifespan of an air compressor. High-end air compressors can last up to 25 years if you take great care of them. However, an air compressor is unlikely to last longer than 6 years if you can’t maintain a normal dew point.

The moisture wears out the valves, damages air tools, and even seeps into the oil. This will water down the oil and reduce its ability to lubricate your air compressor. You can also damage products if water gets into the hose and sprays out, but that’s less of an issue if you have an air dryer.

Cycling Vs. Non-Cycling Air Dryer

Cycling and non-cycling units are the most common types of refrigerated air dryers. They vary in cost, efficiency, weight, performance, and method of operation. Let’s look at how cycling and non-cycling air dryers compare.


Cycling air dryers are popular because of how they work based on your air compressor’s needs. They work efficiently to run or turn off based on the presence of moist air. Cycling air dryers only turn on when your compressor needs dry air, and this can help you maintain a healthy dew point.

They are expensive when you first buy them, but cycling air compressors can save you a small fortune each year. You can save up to $3,500 or more on energy costs with a cycling air dryer since it doesn’t run continually. It only turns on when it’s necessary, so you don’t have to worry about running up a massive bill.

The one downside to a cycling compressor’s ability to turn on and off when needed is that it can stress the system. This can wear out the electrical and mechanical components over time, and that can be a problem in an industrial setting. Cycling dryers are also quite heavy, so you will need some help with installation.


Non-cycling units are another type of refrigerated dryer that essentially runs constantly. That may seem like a good thing, and it can be, but it also adds a lot to your energy bill. They may not cost as much as cycling dryers, but the energy bills are much higher than what you can expect from a cycling dryer.

Because they run constantly, you must still pay for their power needs even when you don’t need it. You can spend up to $12,000 or more in energy bills if you run a non-cycling dryer constantly at a major business. That said, non-cycling dryers are quite effective at eliminating moisture from your air compressor.

The constant running means that the dew point will stay low at all times under the right conditions. You won’t have to worry about dew point fluctuations with non-cycling dryers like you would with a cycling dryer.

What is a VSD Dryer?

VSD dryers, or variable speed dryers, fall into the category of cycling dryers. That said, they are quite different than standard cycling dryers, but they’re much closer to them than non-cycling dryers. As the name suggests, VSD dryers make use of frequencies to change the compressor’s speed to reduce moisture.

Like standard cycling dryers, VSD dryers only run when they need to. VSD dryers are the best option if you frequently adjust your air compressor or need to use it at an unpredictable pace. They can adapt quickly to changes in pressure and moisture, and that’s essential for stability.

For example, air compressors are often susceptible to moisture when you run them for a while, stop using them, then run them again. That’s especially true in a hot and humid environment. You don’t have to worry about that with a VSD dryer because they maintain a consistent dew point.

Refrigerated Air Dryer Vs. Desiccant Air Dryer

It can be hard to choose between a refrigerated air dryer and a desiccant air dryer if you don’t know the difference between them. While they are similar in that they both keep moisture out of your air compressor, they operate much differently. Let’s look at the difference between refrigerated air dryers and desiccant air dryers.

Refrigerated Air Dryer

Refrigerated air dryers use the same principles as air conditioner units to remove moisture from compressors. They simply cool the air to pull moisture from it, and that’s quite useful when you run an air compressor in a hot or humid environment. When the air cools, condensation forms and that may sound counterintuitive.

However, refrigerated air dryers feature traps that collect the water that accumulates. Air compressors already have condensation tanks, but the trap in a refrigerated air dryer is the perfect backup. The dew point will drop to 38 degrees Fahrenheit so you can run a compressor for hours without worrying about excessive moisture.

They offer more variety than desiccant air dryers because there are many more types. You have cycling, non-cycling, and VSD dryers that all fall into the refrigerated air dryer category. Refrigerated air dryers are the best option if you use a compressor to paint cars or clean materials, such as clothes and bedding, as water won’t come out of the hose.

Desiccant Air Dryer

Desiccant air dryers absorb moisture from the air when you run a compressor. The micropores within desiccant dryers increase the potential to absorb and remove moisture. As the name suggests, this type of dryer features towers full of desiccant beads, and desiccant dryers alternate between them while running.

This ensures that neither tower becomes too full of moisture which would make it ineffective. They are generally considered more cost-effective than refrigerated air dryers. While they cost more at first than refrigerated air dryers, desiccant dryers aren’t as expensive to run.

You can choose between heated and non-heated dryers. Heated desiccant dryers use heat to remove the moisture from whichever tower of beads isn’t running at the time. This will help the beads that aren’t in use become ready sooner, and that’s nice if you have to keep up with a lot of work.

Non-heated desiccant dryers instead rely on the beads to absorb moisture and don’t rely on heat. Heated desiccant dryers use more energy, but non-heated dryers aren’t quite as effective.

Refrigerated Air Dryer Maintenance

Refrigerated air dryers are low-maintenance compared to desiccant air dryers. For example, you must replace the beads in a desiccant air dryer every 1 to 2 years besides the basic maintenance. It’s easy to maintain a refrigerated air dryer if you inspect it regularly.

The maintenance schedule for a refrigerated air dryer often lines up with the timing of air compressor maintenance. You must blow out the condenser coils after every 1,000 to 2,000 hours of use. This will ensure that you can still cool the air to reduce and collect moisture.

The suction pressure may weaken after a few years of use, but that is easy to repair. Most importantly, you must remember to clean the strainer and check the drain valves a few times per year or as needed if you notice they aren’t working properly.

Are Cycling, Non-Cycling, or VSD Air Dryers Better?

Cycling refrigerated dryers are the best type of air dryers. VSD air dryers are also impressive because of how quickly they can adapt, and they fit into the cycling dryer category. Non-cycling dryers are cheaper than cycling and VSD dryers, but they cost much more in the long run.

You can spend over $13,000 in energy bills if you run non-cycling air dryers at big workshops and industrial buildings. That is especially true if you use multiple dryers for several compressors, and that’s common in big businesses. Most people prefer refrigerated air dryers over desiccant dryers because desiccant dryers are expensive to use in the long run.

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