What is a Ductless Air Conditioner?

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Updated September 10, 2022

If you are new to the world of indoor cooling, you may wonder what is ductless AC. Some of the best air conditioners, after all, operate without the use of ducts. So what is a ductless air conditioning system, what are the benefits of using one, and is it the right choice for you? Keep reading to find out.


  • Ductless air conditioning systems replace ducts with refrigerant lines, in addition to both an indoor unit and an outdoor compressor.
  • Single-zone ductless mini-split systems are great for regulating the temperature of one area, while multi-zone systems offer whole-home cooling.
  • Ductless air conditioners are energy efficient with an easy installation process, especially when compared to traditional central AC units.

What is a Ductless AC Unit?

Before you can learn how to size a ductless mini-split air conditioner or perform other maintenance tasks, it is helpful to know the exact definition of a ductless unit. As the name suggests, these systems deliver cold air without the need for ducts, instead of transferring the cooled air via refrigerant tubing from an outdoor unit to an indoor unit. There are many types of ductless systems if you are comparing Fujitsu and Mitsubishi air conditioners, but they tend to fall into one of two camps.

There are single-zone systems that are intended to cool a single part of the home, with just one indoor unit to work with. These systems occasionally include heating elements, if you are comparing heat pumps vs air conditioners. There are also multi-zone systems, which increase the number of indoor units to replicate the efficacy of central air. These systems also often include heating features, if you wonder what is a reverse cycle air conditioner.

Insider Tip

Even ductless systems have air filters, so clean and replace the filters as indicated by the instructions.

Benefits of Ductless AC

There are many benefits to choosing a ductless AC system for your home.

Easy Installation

These are fairly easy to install, as pros won’t have to tear into your walls to crate ducts and associated vents. The process still requires an expert, but it is just a matter of placing the outdoor unit and the various indoor units, along with the refrigerant lines and any affiliated materials and hardware.

Preserves Structural Integrity

Ductless systems are the perfect choice for older homes without pre-existing ductwork. This saves on money, as you won’t have to hire anyone to bust into your walls, but also avoids any accidental damage.

Increased Efficiency

Ductless systems are known for being highly efficient, with little heat loss. This translates to increased comfort during the summer months and a decrease in that monthly energy bill. The lack of vents means that the cooled air has a shorter distance to travel after all, which is why these systems increase energy efficiency.


Does a ductless AC purify the air?

As long as your unit features an air filter, it will purify the air. Some allow for air purification via remote control as well.

Does ductless AC need to be vented?

One of the primary benefits of mini-splits and related ductless systems is that they do not require venting of any kind. The same cannot be said for traditional central systems such as ducted systems.

So mini-splits produce carbon monoxide?

Ductless air conditioners and ductless systems do not create carbon monoxide, even when equipped with a ductless heat pump. The same is also generally true of a central air conditioning system and various ducted systems.

STAT: A ductless mini-split system requires basically the same care and maintenance as a traditional split system central heating and cooling system. (source)

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