Photo of a Ductless Mini Split Air Conditioner System
PIONEER Dual Zone Mini Split AC System (Featured in Our Buying Guide)

It seems like everyone is talking about ductless air conditioners these days—also known as mini split AC systems.

In particular, people are drawn to the lower costs and immense benefits that these systems offer over traditional central air conditioning units.

But what is ductless air conditioning and how does ductless AC work?

Those are the questions we’re going to answer in this post.

So, if you’ve been asking yourself, “what is a mini split air conditioner?” you’ll discover everything you need to know below.

If at any time you decided that this is the perfect solution for your home, check out our free guide on the best ductless AC units here. That page compares all of the top models available and helps you determine which one is best for your needs.

What is a Mini Split Air Conditioner Exactly?

Mini split air conditioner, mini split AC, ductless air conditioning, and ductless mini split.

Those are all various terms that refer to the same thing.

A ductless mini split air conditioner is an appliance that lets you regulate the temperature in individual areas of a building.

And it does this without the need for ductwork or access to a window.

That feature alone is what makes these systems the number one choice for many homeowners and businesses.

How Does Ductless AC Work?

On the surface, it’s easy to understand what is a mini split air conditioner.

But, how does ductless AC work to actually cool down and heat up a room?

The concept is actually simpler than it may seem.

Mini split AC systems are composed of two integral parts and each one serves an important function:

  • Indoor Evaporator — This is the unit that actually delivers conditioned air into a room. Evaporators come in two types and can be mounted on a wall or installed inside the ceiling.
  • Outdoor Compressor — This is the unit that powers the indoor evaporator and is responsible for the transferring of hot and cold air in and out of the building.

The reason these systems are called “mini split” air conditioners is because those two components are separated (or split) and they’re much smaller versions (mini) than you’d find on a whole-house central air conditioner.

These systems are also referred to as “ductless” because they don’t use ductwork to transfer hot and cold air. In fact, the only thing that connects the indoor evaporator to the outdoor compressor is a small line set of tubing.

Types of Mini Split Air Conditioners

Ductless air conditioning systems can be grouped into two types and each one serves a different purpose:

  • Single-zone units
  • Multi-zone systems

As the names suggest, single-zone units are designed to cool and heat a single space inside a building while multi-zone systems can deliver conditioned air to multiple rooms at once.

Additionally, multi-zone mini split air conditioners can target anywhere between 2-6 rooms on one compressor. That means you can have a separate indoor evaporator in up to six rooms of a building. If you want to cool or heat more than six areas, you’ll need to purchase another compressor to power those additional indoor units.

What’s also nice about multi-zone systems is that each one provides customized cooling and heating. No two rooms have to be set at the same temperature setting or turned on, for that matter.

Benefits of Ductless Air Conditioning

Now that you know what is ductless air conditioning and how it works, what are the benefits of choosing this type of system?

Here are some of the top advantages of using a mini split air conditioner:

  • Less Air Leakage — Because mini split AC units only require a small 3-inch incision in a wall to connect the evaporator and compressor together, you won’t have to worry about air leakage. Other air conditioning options, like window units and portable air conditioners, need a window to vent out hot air and gaps are often left around the open window frame.
  • Energy Efficient — These types of air conditioners are very energy efficient because they don’t use ducts to deliver conditioned air. Improper ductwork can result in up to a 30% loss of cooling and heating which causes your energy bills to rise. With a mini split air conditioner, you get maximum cooling and heating power without those worries.
  • Flexibility — Ductless AC systems let you match the system to your specific needs. Only need to cool or heat one room? You got it. Need to improve the air quality in four rooms on different levels of a house? You can do that too. There are no restrictions to the number of rooms you need to heat or cool inside a building.
  • Better Security — With mini split AC units you don’t have to worry about someone breaking into your home because they don’t provide an access point. An issue with window air conditioners and portable air conditioners is that they require an open window to function. Therefore, those systems provide an easier access point for burglars to invade your home.
  • Double as a Heater — Ductless air conditioning units don’t just cool the air but can also heat it too, as long as you get one with a heat pump.

Choosing The Right Ductless Mini Split Air Conditioner

A large part of knowing which mini split AC unit is right for you depends on three factors:

  • Number of Zones Needed — If you’re looking to cool multiple areas in your home, you would do best to buy a multi-zone system. If you only want an AC unit to cool one specific room, then a single-unit will suffice.
  • Cooling Capacity — The key to how well a ductless mini split air conditioner works hinges upon its British Thermal Unit (BTU). The higher the unit’s BTU number, the more space (or square footage) the system is capable of cooling.
  • Cooling and/or Heating — If staying cool is your only priority then you can choose a ductless air conditioner that only provides that function. However, if you also want the system to provide supplemental heat in the winter then you’ll need one that also has a heat pump.

After deciding on those few things, you can confidently go shopping for a mini split AC system.

To see what’s available to suit your needs, take a look at our guide on the best ductless AC units here. It includes all of the top models you can buy today, sorted by single-zone units and multi-zone systems.

You’ll also find some helpful buying tips to ensure you get the proper ductless air conditioner for your needs.

We hope you enjoyed this post on what is a mini split air conditioner and how does ductless AC work.

As you discovered, the concept behind what is ductless air conditioning is not too difficult to understand. And, the options you have for finding something that works for your home or business are plentiful.