Installing a Ductless Heat Pumps: A DIY Guide


Ductless heat pumps are small, versatile, and incredibly flexible when it comes to heating and cooling some areas of your home. They are also, admittedly, the easiest to install compared to other home conditioning systems.

You may be thinking of installing a ductless heat pump yourself to save money. Some ductless systems are designed for DIY installation, while others require some technical skills. DIYers with intermediate skills can install a ductless heat pump themselves.

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The fact that there are no ducts makes them not just more efficient but also a lot easier to integrate into one’s home. In addition to that, ductless heat pumps are also cheaper compared to some other systems.

All of these are great incentives because of which many homeowners will entertain the idea of installing the whole system by themselves. 

But is this feasible? 

Do you have questions about the best uses for a ductless heat pump? See our article 11 Best Uses for a Ductless Heat Pump.

This is the topic that we will explore in this article.

Safety Tip: Installing a ductless heat pump requires some electrical work. Working with electricity can be deadly and should only be undertaken by a licensed electrician.

Can You Install a Ductless Heat Pump by Yourself?

Let’s take a closer look at if you can install a ductless heat pump by yourself.

You can install a ductless heat pump by yourself. However, in order to install the ductless heat pump properly, you will require some technical skill, special tools, and the help of another person. In some instances, you may also need the help of a licensed electrician to finish the job.

For a very good and in-depth look at how to install a ductless heat pump by yourself, make sure to check out these videos. They will give you a good perspective of the work at hand, and you will be able to decide if you will need any help from a professional.

Seeing that a well maintained ductless heat pump can last 18-20 years, for the cost and ease of installation, they make a great choice for your home.

Let’s look at 6 reasons why installing a ductless heat pump is not a DIY job and 4 reasons it is a DIY job.

6 Reasons Why Installing a Ductless Heat Pump is Not a DIY Job

Although technically speaking, you can install a ductless heat pump by yourself, there are several reasons why you may not want to do so. 

  1. It May Be Difficult to Calculate the Heat Load
  2. The Installation of the Indoor Unit Is Not a One-Man Job
  3. You May Not Have the Right Tools
  4. The Installation May Require a Good Level of Handiness
  5. You May Need Help From a Professional
  6. You May Not Be Legally Allowed to Carry out the Full Installation

Let’s take a closer look:

It May Be Difficult to Calculate the Heat Load

The first and most important reason why you may not want to install a ductless heat pump by yourself is that it may be difficult to make the necessary heat load calculations.

This is the first step that needs to be taken even before considering buying a ductless heat pump.

To find what size of a ductless heat pump you need for each room, you need to find how much heat will be lost to the outside on the coldest day, and alternatively, how much heat will be gained from the outside on the hottest day.

A company specializing in such installations may be better able to do a well-educated calculation on what the actual heat load for each room is.

The risk you are facing by doing this calculation by yourself is that you may end up with a ductless heat pump that is not adequately sized.

When it comes to heat pumps, of any kind, bigger is not better. You want a heat pump that is suitable for the area in which it will be used—neither too big nor too small.

When the heat load is calculated, multiple variables are taken into account:

  • The size of the area.
  • Local climate and the year-round temperature fluctuations.
  • The condition, number, and type of windows.
  • The insulation in the walls, ceiling, and floors.

There are three outcomes: you can either (1) size the ductless heat pump properly, (2) oversize it, or (3) undersize it.

There is a good reason why I am stressing this: homeowners frequently overestimate what size of a heat pump they need, which ends up costing them more and causing them more problems than necessary.

Naturally, you want the system to be correctly sized for each particular area.

Choosing the wrong size of a heat pump will result in short-cycling, higher energy bills, inability to keep the humidity in adequate percentages, temperature, and airflow inconsistencies, and overall poorer performance. This makes the heat pump inefficient and more costly; it can also speed up wear and tear and cause it to fail sooner than expected.

Additionally, oversizing the ductless heat pump will also mean that the unit itself will cost more. Sometimes a higher capacity unit itself may cost as much, if not more, as a lower capacity, but properly sized, unit including the installation and labor costs.

The Installation of the Indoor Unit Is Not a One-Man Job

The installation process of a ductless heat pump usually starts with placing the indoor unit on an outside wall. For this, you will need to mount the bracket using the screws that come with the heat pump.

The indoor units may weigh between 15 and 35 pounds. Although the bracket may be easy to lift and mount to the wall, lifting the indoor unit may be very difficult for a single person. You will need to fit the wires through the connecting hole to the outside while, at the same time, lifting up the indoor unit and attaching it to the bracket.

The installation of the outdoors unit may be even more difficult to do as it can weigh between 60 and 90 pounds. (It is a lot heavier because it also holds the refrigerant.) 

The outdoor unit is not placed as high as the indoor unit. However, it needs to be placed either on two brackets or on a concrete pad, which requires lifting the unit. The outdoor unit should be lifted off the ground as dirt, water, or snow may get inside and cause problems.

As you can see, the outdoor unit is a heavy piece of equipment, too, so help from another person may be needed in order to avoid any injuries.

You May Not Have the Right Tools

The installation of a ductless heat pump involves various kinds of drilling and cutting.

At the very minimum you will need:

  • A power drill capable of drilling a 2 5/8″ or 3″ inch hole in the wall. To do that, you will also need a circular hole saw drill bit. A wooden wall will be easy to drill through, but if you live in a concrete apartment or home, you will need a heavy-duty drill capable of drilling concrete. You will then also need to drill another hole for the installation of the outdoor weathertight manual disconnect switch box.
  • A utility knife and a wire cutter.
  • A screwdriver bit set is used for attaching and securing the screws for the mounting plate for the indoor unit, the hanging brackets for the outdoors unit, and the tubing that covers the lines.
  • An adjustable wrench and a torque wrench.
  • A leveling tool to make sure that the indoor and outdoor units are all horizontal.
  • You will also need at least one ladder to reach the area where the indoor unit will be installed.
  • Usually, professionals use tubing benders to bend the copper wiring without breaking or kinking it. If you don’t have one, you can try bending it very slowly in order to avoid any kinks, as this could block the refrigerant from freely flowing.
  • To connect the refrigerant lines to the outdoor unit, you will need to use a flaring tool. (It can also be used to cut the copper wiring to the appropriate size.) The flaring tool deforms the end of the wire in such a way as to provide a tight high-pressure seal.
  • A two-stage vacuum pump and manifold gauge are also needed to create a vacuum in the lines. This is a necessary step in order for the refrigerant to run inside the lines and to ensure that there are no leaks anywhere in the system.
  • To let the refrigerant out and into the lines, you will also need an Allen key.
  • You will need some tape to wrap the wiring and lines that go from the indoor unit to the outside.
  • You will also need spray foam to fill in the opening in the wall where the wiring and the lines go through.
  • Do not forget to use safety glasses and work gloves for protection.
  • If you need to install a good solid base for the outdoor unit, you will need to mix and pour your own concrete base. This is not exactly a very specialized kind of work, but it is little labor-demanding and will require certain tools like a bucket, a mixing tub, a rake, or some other tool you can use to mix the concrete with the water, a frame, and a trowel to make the concrete surface smooth.

As you can see, you will have to have a good amount of various tools. I don’t claim this to be a thorough list but rather an example of how many tools you may need.

However, having these tools is not enough as you will also need to know how to use them in a proper and safe way.

The Installation May Require a Good Level of Handiness

During the installation of the ductless heat pump system, you will be required to drill holes, attach and connect different connectors, lines, electrical cables, use various tools, saw, cut, and so much more.

After the mounting bracket has been securely attached to the wall and the connecting hole has been drilled, you will move on to the indoor unit installation, after which there will be several connections that you will need to make (usually four).

There are two connections for the refrigerant line, a condensate line, and one electrical line. All four connections need to be well-made. A loose connection can cause multiple problems. For example:

  • A poorly fit and attached refrigerant line can cause a refrigerant leak and subsequently damage the heat pump. 
  • A poor electrical installation is a latent fire and health hazard.
  • Using power tools can also be very hazardous, and extra care is to be exercised at all times. 
  • Doing electrical work, running a new circuit on a new breaker is even more dangerous.

What I am trying to say is that if you do not consider yourself handy, this may be a job best left to an experienced professional.

You May Need Help From a Professional

Wiring the electrical is relatively simple and straightforward for people with experience, but it may be too difficult for people without any prior knowledge. The electrical connections are usually numbered, and all you need to do is color-match the wiring. There should be detailed schematics on the panel of the unit, including more information in the manual.

There are different units with different sizes, and things can change, so it is of utmost importance to follow the instructions and the schematics.

To power the outdoor unit, it is required to run a new circuit to it.

This usually requires a professional electrician to come and run a new line to the outdoor unit, which must be installed on a separate circuit breaker, and it has to run through a separate exterior-mounted manual disconnect switch.

Depending on where you live, you may need to first apply for a permit to do the electrical work.

And lastly, you may need to call in a professional to remove air and create an appropriate level of vacuum in the line. (Although, some systems may be installed without the need for a vacuum pump.)

You May Not Be Legally Allowed to Carry out the Full Installation

You may have all the necessary knowledge to install your ductless heat pump, but if you are not legally allowed to do that, you may run into some trouble.

Homeowners are also recommended to speak with their local permitting authority in order to find what work they are allowed to carry out. You may or may not be allowed to do the electrical installation by yourself, depending on where you live.

In some instances, you will have no other choice but to hire a contractor, while in others, you may be allowed to do all the work by yourself as long as you get the necessary permits.

And this is a tough one. Some homeowners may have grandfathered electrical setups that may need to be upgraded up to the current code because of a simple installation like this.

For example, if your breaker box is full and there is not a single open space for a new breaker that will be servicing the heat pump, you may need to install a sub-panel, a bigger main panel, or tandem breakers. You may not be required to get permission for a tandem breaker, but you may need one if you will be upscaling your breaker box or installing a sub-panel.

In order to find out, make sure to speak to your local building, code and permit office as in some instances even if you are allowed to carry out the installation, it will still need to be inspected by the county and signed off.

4 Reasons Why Installing a Ductless Heat Pump is a DIY Job

Admittedly, it can be challenging to find a qualified professional that knows how to work and install a ductless heat pump. At the same time, nothing prevents you from doing the work by yourself. You may not have another choice but to consider doing it by yourself.

Let’s look at 4 reasons why installing a ductless heat pump can be a DIY job.

  1. There Are DIY Ductless Heat Pump Kits
  2. It Is Significantly Cheaper
  3. If You Have the Necessary Knowledge and Experience
  4. If You Already Have All the Necessary Tools and Permits

Let’s take a closer look:

There Are DIY Ductless Heat Pump Kits

Some companies sell DIY ductless heat pump systems. The neat thing about these is that they are designed to be installed by individuals without any specialized HVAC tools. These systems are usually pre-charged with the necessary refrigerant and also have pre-flared lines.

These often come with ready to use drilling templates for where the indoor unit will go, in-depth manuals, and additional small touches intended to allow homeowners to install and connect both the indoor and outdoor units easily.

Some ductless heat pumps can have a SEER rating of 30 or more. One of the best DIY ductless heat pump systems is the one sold by MRCOOL DIY Ductless Heat Pump , which can be seen in the videos below:

It Is Significantly Cheaper

Obviously, the main advantage of installing a ductless heat pump by yourself is that you will not be paying labor costs or any installation costs to anyone else. However, this will cost you at least several hours of your free time.

Frequently the quotes may be in the ballpark of $2,500 to $10,000 (and more). 

Not to mention that these quotes often do not include the patching work, cleanups, or any hauling of the old system or furnace work.

In comparison, installing the ductless heat pump by yourself may end up being two to three times cheaper, if not even more, as you will be paying only for the unit.

If You Have the Necessary Knowledge and Experience

One should consider the possibility of installing a ductless heat pump by themselves only if they possess the necessary knowledge, experience, and understanding of how electrical systems work.

Although you will find pretty extensive and in-depth information about each step of the installation process, you will still need some general knowledge and understanding of how electrical and heat pump systems work and some decent level of handiness.

If you do not consider yourself handy or knowledgeable enough, it is not recommended to carry out the installation of the ductless heat pump by yourself as this could place you, your home, or the ductless heat pump in danger.

If you do not feel comfortable with the scope of the work, it is better to hire a professional. Saving a little money is not worth the potential risks.

If You Already Have All the Necessary Tools and Permits

Well, if you are confident in your abilities and know what you are doing and are legally allowed to carry out the full installation of the ductless heat pump, there is no reason why you should not do it, especially if you already have all the tools you will need.

Of course, there is an alternative, which oftentimes will be a better call, which is to handle the physical work yourself, including the mounting of the units, running the lines and setting up the whole system, and leaving the rest to a professional. They will charge the system if it needs to be charged, connect the lines, and set up the electrical.

This is usually a good way to go about it as it allows you to save on some money while still having a trained professional take care of the most vital and sensitive steps of the installation process.

Finally, for more information on SEER ratings and heat pumps, see our article Complete Guide to Heat Pump SEER Ratings.

In Closing

Installing a ductless heat pump can be a DIY job with the right skills and the help from a friend. While this can be a DIY job, you’ll need someone to help mount the inside unit particularly. You’ll also need the help of a licensed electrician unless you have some basic electrical skills.

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Get a free estimate from top-rated, screened, and licensed HVAC contractors in your area!

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Hubert Miles

I've been conducting home inspections for 17 years. I'm a licensed Home Inspector, Certified Master Inspector (CMI), and FHA 203k Consultant. I started HomeInspectionInsider.com to help people better understand the home inspection process and answer questions about homeownership and home maintenance.

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