Ductless Air Conditioning Buyer’s Guide for Homeowners

A man working on an Air Conditioner

Thinking about buying a ductless air conditioner system?

You probably have plenty of questions, and I don’t blame you!

Each home has unique needs when it comes to air conditioning. And if you have a home that doesn’t already have ductwork, or has ductwork that would require a complete overhaul, then ductless air conditioners may be the right choice for you.

Ductless air conditioning is a fantastic solution – but it’s important to ensure you get the right one for your home.

The good news is that you’re in the right place. Here at Appliance Analysts, we have decades of HVAC and appliance experience!

In this article, I’ll cover everything you need to know about ductless air conditioning and give you the information you need to choose the best option for your home.

Why trust us? This article was written by Craig Anderson and Alan Stephens.

Craig has helped thousands of homeowners repair their appliances since 2016.

Alan is one of our resident appliance experts with 20+ years of experience. He holds triple HVAC certifications in North Carolina, and, since 2004, has operated his own business, Eco Green Air Inc.

Types of Ductless Air Conditioners

Ductless air conditioning systems are great for many things – and, in my opinion, one of them is versatility. Depending on your home and needs, there are several ductless options you can choose from, such as:

  • Wall mount.
  • Floor mount.
  • Ceiling recessed.

Wall Mount

Mini Split Installed on the wall
A wall-mounted Mini Split

Since wall-mounted ductless Air Conditioners are the most popular type, you’ll have many choices when shopping. Wall-mounted units are mounted close to the ceiling, and airflow is pushed down into the room.

Floor Mount

Despite being called a floor mount, these Air Conditioners aren’t installed on the floor. They’re still installed on the wall, but instead of near the ceiling, they’re near the floor, and airflow is pushed up into the room.

I tend to find that a great advantage of floor-mounted Air Conditioners is that they’re easy to clean and maintain.

Ceiling Recessed (Cassette)

First, to install ceiling recessed Air Conditioners, you’ll need at least 10 inches of clearance above the ceiling where you want it to go. The housing is installed above the ceiling and pushes the conditioned air in four directions at once.

And then we break those down a little for some other options.

  • Single zone.
  • Multi-zone.

Let’s talk a bit about the attributes of each.

Single Zone

A single indoor air handler attached to the outdoor unit. 


If you want to cool more than one room, a multi-zone mini-split can have up to four air handlers attached to the outdoor unit. Each indoor unit can function independently of the others.

Ductless Mini Split Buying Considerations

Now that you know what a mini split or ductless air conditioning system is and the types available, let’s talk about everything you need to consider before purchasing.

Indoor Unit Placement

For a mini split to work properly and efficiently, the indoor unit should be installed somewhere that allows for the best airflow. You’ll also want to be sure you have easy access to change the air filter when necessary.

Most importantly, your ductless air conditioner needs to be placed in a spot allowing the installer to connect it to the outdoor unit and the condensate pump’s drain to work properly. Additionally, the outdoor unit needs a solid level surface that allows for sufficient clearance and is close to wherever you want to put the indoor unit.

Here are a few placement guidelines:

  • Install on an exterior wall: Ideally, your indoor unit should be placed on an exterior or perimeter wall, as it allows for the best connection between the indoor and outdoor unit. If you must install an air handler on an interior wall, be aware that it will increase your installation costs and time since the hookup will be more complex when it comes to electrical connections and how the refrigerant line is installed. Additionally, since you don’t have a direct path between the indoor and outdoor units, you’ll likely need to have a condensate pump installed as well.
  • Avoid electronic devices: If you install the indoor unit near anything that generates heat, such as computers, televisions, or light fixtures, your air conditioner may lose its ability to gauge interior temperatures.
  • Ensure you have a direct path: Don’t place your indoor unit anywhere airflow can be blocked. Potential airflow blockers include furniture, wall hangings, and shelving units.
  • Allow for optimal air distribution: Pairing this with the need to install your air handler on an exterior wall may present a bit of a challenge, but you want a location that allows for the best air distribution to the entire room. If you’re considering a wall-mounted ductless air conditioner, these must be placed between 6 and 7 feet from the floor and not too close to the ceiling. However, each manufacturer will have their own guidelines and recommendations, so be sure to follow them.
  • Install vertically: Your wall mount mini split should never be installed on the ceiling or on an angled wall, but rather on a vertical wall only, and secured with studs.

Outdoor Unit Placement

While there aren’t as many outdoor guidelines as there are indoors, there still are a few important things to consider:

  • Municipal bylaws: Be sure to check any local bylaws around outdoor air conditioning units and follow them.
  • Avoid obstructions: Bushes, shrubbery, or anything else that gets in the way of airflow is undesirable. Much like a more traditional central air conditioner units, outdoor units need maximum airflow, so be sure to allow for several feet of space around them. It’s also best to have the unit a few inches above a pad to allow for drainage in the heating season.
  • Level surface: Whether on a concrete or composite pad, your outdoor unit must be on a solid, level surface.
  • Rooftop or wall mount: The outdoor unit can be placed on either, and in the case of wall mounting, it must be done with specifically designed mounting hardware.
  • Distance from the house: Outdoor units can be placed up to 100 feet away from the indoor unit, but the farther away they are, the more they’ll cost you to run since the distance causes them to lose efficiency.

Cooling Capacity

To calculate cooling capacity (the size of the air conditioner you need to purchase), you need to know the room’s square footage or area that you plan to cool. My usual advice is also to consider whether you have a single-zone or multi-zone mini-split.

The BTU output of the outside unit and the inside air handler is the same if you are looking at single-zone systems. However, a multi-zone system will differ in that the outdoor unit will be a multiple of the individual indoor units.

For example, if you have an outdoor condenser with an output of 40,000 BTUs, you could have four indoor air handlers with 10,000 BTUs each. But since individual rooms in your home are likely of different sizes, their corresponding air handlers don’t need to have an equal number of BTUs.

While it’s always best to have a professional calculate cooling capacity, the following table will provide you with a ballpark estimate:

Room or Area You’d Like to CoolNecessary Cooling Capacity
150 to 250 sq ft6,000 BTUs
250 to 300 sq ft7,000 BTUs
300 to 350 sq ft8,000 BTUs
350 to 400 sq ft9,000 BTUs
400 to 450 sq ft10,000 BTUs
450 to 550 sq ft12,000 BTUs
550 to 700 sq ft14,000 BTUs
700 to 1000 sq ft18,000 BTUs
1000 to 1200 sq ft21,000 BTUs
1200 to 1400 sq ft23,000 BTUs
1500 and above sq ft24,000 BTUs

Why do I say a professional is a good idea? Because, in my experience, calculating cooling capacity includes more than simply square feet. Here’s some of the additional key factors to consider.

Environmental Factors

An important part of the cooling capacity equation is environmental factors. Any and all of the list below are factored into the equation and either increase or decrease the number of BTUs required.

  • Ceiling height.
  • Climate.
  • Electronics and appliances that create heat.
  • Insulation.
  • Windows — do they get direct sunlight?

Please refer to the Energy Star website for further information on how environmental factors impact cooling capacity.

Installation Cost

For the most part, if you’re purchasing a window or a portable air conditioner, you can install it yourself. However, you typically need a professional to install a mini split, and professional installation can cost anywhere up to $2,000 per zone.


When it comes to central air conditioners, you don’t see anything in your living space. Unless you’re in your basement or somewhere outside, you don’t see the condenser or the air handler.

Keep in mind, though, that a mini-split’s air handler will essentially become part of your decor. Each room you’re cooling will have a wall unit, either at the ceiling or floor level, which can be a dealbreaker for some people.

But if you’re hot and can’t install central air, I bet most people will quickly move beyond their distaste.

What are Ductless Mini Splits?

In my opinion, one of the main reasons ductless Air Conditioners are called mini splits is because of their small size. Especially when compared to a huge central Air Conditioning unit or even a window or portable Air Conditioner.

Mini-splits are compact units broken out into two components—one for the inside and one out. Depending on the system, you can have multiple indoor units attached to a single outdoor unit.

The outdoor unit contains the condenser and compressor, and the indoor unit is the air handler. They’re attached by a conduit running through an exterior wall, which houses the cables and tubes necessary for power, refrigerant, and condensate drain.


We can’t tell you which ductless air conditioner is best for you. Only you can do that. But we have provided you with most, if not all, of the information you need to make an informed decision.

So go through each of the considerations mentioned above and evaluate what they mean to you, if anything.

For example, can you stand looking at air handlers on your wall? Some people will care, and some won’t.

Think about the price to purchase and install. Can you afford to spend upwards of $9,000, depending on the system you need? Or would you be better off installing a few portable or window air conditioners?

Do you have usable space both inside and outside for air handlers and condensers? And remember, there are stipulations on where the outside condenser can be placed. Make sure you can work within those guidelines.

And finally, if and when you decide that a ductless mini split is the right choice for you, be sure to do your due diligence when it comes to installers. Don’t just hire the cheapest. Get some quotes, check reviews, and hire an HVAC company that will do the job right.

Frequently Asked Questions

What Are the Disadvantages of Ductless Mini-Split Systems?

They can cost just as much as a traditional central air conditioner. Additionally, it’s very important to size your system correctly. Otherwise, your system will short cycle, leading to increased costs and an inability to control temperature or humidity efficiently.

What Is the Lifespan of a Ductless Mini-Split System?

10 to 30 years, so an average of 20 years.

Do Mini Splits Require Annual Maintenance?

Yes. Failure to do so may void your warranty.

I've been helping homeowners with appliance repair since 2016. Starting out as an enthusiastic amateur, I've since worked with many Appliance, HVAC, and DIY experts over the last 7+ years. My mission is to help fix your appliances and prevent future issues - saving you stress, time, and money. Visit my author page to learn more! Read more