How Do Ductless Air Conditioners Work?

Before I get into the details of how these products work I want to first remind that you air conditioners more or less all work the same way. There is a cycle of refrigerant changing states from liquid to gas. This change of state allows heat to be dissipated. When the heat is removed the blower motor or fan then blows the now cold air back into your room. For a more in-depth explanation please check out our ‘How do Refrigerants Work,’ article which dives deep into the mechanics of refrigeration and air conditioning.

All that being said, if you are looking for a short overview then by all means continue reading. This part of our guide is divided into a few different sections.  They are:

  • The different parts of a ductless air conditioner
  • How the parts of the ductless air conditioner interact

It makes sense to know what the parts are before you can understand how they interact with each other. I already gave a top-down view of mini split systems when I said one unit is indoor and the other is outdoors. This is very important! And you’ll know why once I get to how it works. But first, let’s take a look at the different moving pieces of this amazing air conditioning system.

The Different Parts of a Ductless Air Conditioner

The ductless mini split is two separate parts; however, they are connected. The outdoor unit includes an inverter-driven variable speed compressor, a condensing coil, and an expansion valve and a fan which cools the condenser coil. The indoor unit includes the quiet oscillating fan and an evaporator.

In addition to the indoor and outdoor units, they need to be connected somewhere. That’s where the refrigerant line-set comes into play. It’s made of insulated copper tubing, which protects the liquid/vapor. The insulated copper tubing is enclosed in a conduit next to both a power cable and a condensation drain.

You could technically include a remote control (which is often included) as one of the parts do ductless air conditioners. They need no special introduction other than what they do: turn on and off the ductless air conditioner. The remote control sometimes has additional features, however. We’ll talk about those later when we talk about the best mini split products on the market.

So we have the compressor, condensing coils, expansion valves, insulated copper tubing, and more! I hope you like mechanical systems because you’re about to find out how these different parts work with one another (if you don’t know already).

How Mini Split Systems Work

I suppose many people will press the “on” button, feel the cool air, and move on about their day. There’s nothing wrong with that! For those who want to know the how, keep reading. It comes down to a matter of science, actually. You also need to know the refrigeration cycle. The moment you press the on button, the gears start spinning.

Mitsubishi has a great explanation of how ductless systems work. Yes, that Mitsubishi. Let’s first take a look at the refrigeration process. Mitsubishi explains “in the refrigeration cycle, low-pressure gas is transformed into high-pressure gas by the action of a compressor. The heat is dissipated into the outdoors by the action of a forced air fan. The refrigerant then becomes a high-pressure liquid, and it is again changed into a low-pressure liquid by a metering device at the evaporator coil. Heat energy from the indoor air is absorbed by the refrigerant, and the resulting cooler air is pushed into the living area by the internal blower. The resulting low-pressure gas is moved through the suction line back to the compressor, and the cycle is repeated again.”

The story of how the ductless air conditioner works is actually the story of how refrigerant works. And, as you know, we love talking about refrigerants here, seeing as how this is RefrigerantHQ!


Well, there you have it, folks! I hope that I was able to answer your question and also shed a bit of light on ductless air conditioners in general. If you find yourself wanting to read and learn more about ductless air conditioners then I highly suggest you take the time and read our in-depth buyer’s guide.

Remember though folks, that ductless units aren’t your only option. After reading this article if you find that you are leaning towards an alternative air conditioner such as a portable or window unit consider checking out our best of guides on these. Read our best window air conditioner article and our best portable air conditioner article. There are many ways to stay cool nowadays, the question is which one will you choose?

If you have any further questions about ductless air conditioners you can contact us. Also, if you want more guides and articles like this, make sure you subscribe to our email list. As always, thanks for reading! And make sure to return in a few days for a new article from RefrigerantHQ.