Can a Ductless Mini Split Heat and Cool?

Ben Giesbrecht

It's that time of year when you need to make sure that your air conditioning and heating system are working. Maybe you are in need of a new one and want to make an educated and financially sound choice. Today let’s take a look at Mini Split Air Conditioners- one of the many options you have for making your home more comfortable.

Properly configured, a Ductless Mini Split is able to heat and cool whatever space it is in. It heats or cools by circulating air through an evaporator coil in the indoor unit that is in turn heated or cooled by refrigerant lines connected to the outdoor unit.

With that basic question answered, let's dive deeper into what a ductless mini-split is made of, how a ductless mini-split works, and the benefits and costs of using this form of heating and cooling system.

What are the Components of a Ductless Mini Split?

There are many components in a ductless mini-split that are similar to other heating and cooling systems. In fact, it is a miniature split ac system just minus the duct work. The two main pieces of the system are the Indoor (air handling) Unit and the Outdoor (condensing) Unit.

The Outdoor Unit

The outdoor unit has 3 main components:

  • Compressor- this is what compresses the refrigerant, increasing its temperature
  • Condenser Coil- a coil of thin metal tubing that the compressed refrigerant circulates through
  • Condenser Fan- blows air across the condenser coil to remove heat from the refrigerant

One neat thing about outdoor unit is it can be placed up to fifty feet away from the indoor units. This means that you can place the outdoor unit in a place that is unobtrusive without worrying about where you want the indoor units. Your indoor unit could be in the front of your home while the outdoor unit is behind your house.

The Indoor Unit

The indoor unit also has 3 main components:

  • Evaporator Coil- similar to the condenser, this is a coil of metal tubing that allows the refrigerant to absorb indoor heat and cool the surrounding air
  • Blower- the fan inside that blows across the evaporator and distributes the now cooled air across the room
  • Thermostat- your controls for the system and what keeps your space consistently comfortable

What a Mini Split Doesn't Have

Ducts! Ok there are some ducted mini splits out there but really those are just small AC systems.

The lack of ducting is what gives a mini split its efficiency and flexibility. Instead of pumping conditioned air through an unconditioned attic with only a thin layer of insulation in between, a mini split is conditioning the air right in the room with you. No potential for leaking ductwork to reduce the efficiency of your system.

And since there is no ductwork to install, a mini split can fit in much tighter spaces, in garages, workshops, or anywhere installing new ductwork would be a major project.

What about Heating? Those descriptions sound a lot like cooling to me!

The solution is simple and ingenious! When you put a mini split in heating mode, the whole operation works in reverse. The condenser becomes the evaporator and visa versa. Heat is extracted from the outdoor air and released inside your home or workspace.

Where can you Install a Ductless Mini Split?

You can install a ductless mini split in just about any space! To answer where in that space you can install the indoor unit depends somewhat on which indoor unit you select.

The two main types of indoor units are wall mounted and ceiling mounted. Wall mounted is the most common type and lends itself well to locations without an attic space or where the attic is difficult to work in.

Ceiling mounted "Cassettes" have a sleek, very modern look. They fit flush to the ceiling and are perfect as a replacement for a home's central air system. The downsides are the attic space required to mount the unit.

Another consideration when choosing a mini split system is how many rooms or how large of a space are you wanting to condition and how many indoor units will you need to accomplish that. Depending on which outdoor unit you have, up to four indoor units can be connected to one outdoor unit.

Why a Ductless Mini Split Instead of Other Systems?

Ultimately, you need to consider a few specific factors and qualities of ductless mini-splits versus the more traditional heating and cooling methods to determine what air conditioning method is right for you. The most important factors to consider are the type of space to condition, energy efficiency, and price.

The Space

Some homes have ductwork already installed. That means that traditional air conditioning units are a lot easier to install assuming the ductwork is in good shape. Other spaces don't have ducts at all, or maybe a portion of the home don't have air ducts. In order to install an air conditioning unit, you are left with two options.

  1. You have to install some ductwork or
  2. You go with a ductless mini-split.

Depending on your situation installing ducts could be more expensive and disruptive to your space than a mini split. Consider what it would take to add ductwork to the bottom floor of a two story home- the ceiling would need to be cut open all over the place.

Energy Efficiency

One of the primary things that draws people to mini splits is their efficiency. We touched briefly on some of the benefits that come from ditching the ducts but did you know traditional heating and cooling systems that use ducts lose about 30 percent of their efficiency in the air ducts?

Another huge advantage mini splits have is only conditioning the rooms you are using. With a central air system your only option is to condition the whole place at once. Sure, you can shut off vents but this doesn't actually save energy. In fact, restricting the air flow on a traditional AC will make it work harder and shorten its life.

This isn't the case with a ductless mini-split. Turn it on when you enter the room, turn it off when you leave. Your electric bill will show the difference!

System Cost

This is where things get tricky. Each scenario needs to be considered on its own with lifetime cost and comfort considered as well.

A barebones mini split installed in a garage could be around $4,500 installed. Is that more expensive than a traditional system? Well.... a traditional system can't really duplicate that application so is it a valid comparison?

On the other hand replacing your existing air conditioning system with mini splits is most likely going to cost well north of $20,000. That's a comparison that has an easy winner for most homes that aren't in need of major updating.

Here are some typical scenarios and how a mini split stacks up:

1. If you are building a new home and are comparing the 2 options a mini split system will be more expensive to install than a traditional ducted system. Will the lifetime costs be more? I doubt it but that depends on how much you run your system.

If you match the traditional systems energy efficiency rating to the mini splits rating and opt for a zoned duct system so you have similar functionality to a home heated and cooled by mini splits the price starts getting too close to call.

2. What about when you are replacing an AC system on an existing home? In most cases, even if you replace the accessible ductwork, a traditional system will be cheaper.

3. The scenarios that tilt hard in the direction of a mini split are when you want to add air conditioning to someplace like a garage or workshop where a ducted system is hardly a realistic option, or when you are adding on to your home and need additional conditioning capacity beyond what your existing system can provide.

Another perfect use case for a mini split is if you want single room zoning in a master bedroom suite or something similar. Even a zoned central AC system cannot accommodate that small of a heating and cooling zone. If you want one room to be a different temperature than the rest of the house a mini split is the way to go.


Mini splits are great systems for a lot of applications. The only way to know for sure if one would be the best choice for you is to have an expert look at your space and give you an accurate quote on the different options available.

Cosmic Comfort is happy to provide 100% free quotes for system installations and our experts are ready to help you in any way they can. Contact us today to set up an appointment.