Installation and Review: MRCOOL DIY Ductless Mini Split Air Conditioner Heat Pump

By | March 10, 2024

Review MRCOOL DIY Ductless Mini Split Air Conditioner Heat Pump
Mini split heat pumps are very popular since they cost much less compared to traditional HVAC systems.

They are also very popular with the DIY crowd since kits can be bought and installed by a homeowner with no need for an expensive HVAC company.

Mr Cool is one such mini split DIY kit that can be bought online and installed.
How To Install MRCOOL DIY 12K BTU 17.5 SEER Ductless Mini-Split Heat Pump WiFi Done Son
Their units are built mainly for the DIY handy person in mind with many features that make an install easier.

Mr Cool Mini Split Easy Install Features

  • (Quick Connect) Line-Set Pre-Sealed
  • Control Lines Clearly Labeled
  • Standard 120 or 230 Volts Units

Mr Cool mini split unit is one of the friendliest mini split for DIY installs.

The main feature that makes an install easier is the Pre-Sealed Quick Connect line set.
Review MRCOOL DIY Ductless Mini Split Air Conditioner Heat Pump Sealed Line Set
A line-set is two small copper lines that pump refrigerant between the inside and outside side units.

Most DIY Mini Split kits require hooking up a vacuum pump and HVAC gauges to pump a unit down into a vacuum.
Review MRCOOL DIY Ductless Mini Split Air Conditioner Heat Pump Sealed Line Set 2
Mr Cool units come in a vacuum with a seal at the tips of the line-set, which is broken when it is attached to the outside unit.

Since there is no need for a vacuum pump or HVAC gauges, Mr Cool mini split units are much simpler to install.

Keep in mind pumping down a unit into a vacuum is not that difficult, with many YouTube videos showing the process.

The Mr Cool control wires are also clearly labeled, which makes it easy to hook up.
Review MRCOOL DIY Ductless Mini Split Air Conditioner Heat Pump Wireing
Three control wires are used between the inside, and outside units labeled 1, 2, 3, along with 120 volts AC labeled L and N.

120 vs. 230 Volt Unit

The unit I installed is a 120 volt system and needed electrical run to the outside condensing unit.
Review MRCOOL DIY Ductless Mini Split Air Conditioner Heat Pump New
The electrical AC wiring is not included and will need to be run from a breaker.

Mr Cool also sells 230 volt systems if a bigger unit is needed.

120 volt wiring is simpler for most to setup since it is the main voltage used in most homes.
Review MRCOOL DIY Ductless Mini Split Air Conditioner Heat Pump Electrcial 2
An electric disconnect box should be hooked up next to the outside unit to turn the power off.

Other mini split kits can also be bought in 120 Volts or 220 volts systems.

Mr Cool Mini Split Installation

Mr Cool units, in my opinion, are the easiest mini split systems to install and are built for DIY type individuals.

While easier to install, some basic construction skills will still be needed.

A 3 1/2 inch hole will need to be drilled through the wall to run the line-set and control lines.
Review MRCOOL DIY Ductless Mini Split Air Conditioner Heat Pump Instalation
Also, the 120 volt or 240-volt electricity will need to be run to the unit from a breaker.

The installation is not difficult for a handy person with some basic skills.

If in doubt, be sure to call a professional.

Read Here For How I installed a Mr Cool Mini Split Unit

Mr Cool Mini Split Pros and Cons


  • Built for the DIYer
  • Line-Set Pre-Sealed (No Need for HVAC Gauges or Vacuum Pump)
  • Control Lines Clearly Labeled
  • Standard 115 Volt or 230 Volt Units


  • Requires drilling 3 1/2 inch hole in the wall
  • Electrical Needs to Be Run
  • Cost More than other Mini Split Kits

*This post contains affiliate links.
Read More Review Here on Amazon
MRCOOL – DIY-12-HP-115B25 DIY 12k BTU 22 SEER Ductless Heat Pump Split System 3rd Generation – Energy Star 120v (DIY-12-HP-115B)
Mr Cool Mini Split heat pump is a good unit that works very well for both heating and cooling.

Do-It-Yourself type individuals will find it to be the simplest to install.

There is no need to buy and operate HVAC gauges or a vacuum pump, which many find confusing.

While easier to install, it does cost more compared to other DIY kits.

I installed a Mr Cool unit in my garage (See video below), and it has been working very nicely, heating in the winter and cooling in the summer.

The unit heats and cools very well with a remote control that makes it easy to operate.

The 22 SEER rating is also very good and makes it a very efficient unit.

Higher SEER units can be bought, but 22 SEER is currently one of the best SEER ratings for a unit.

My thoughts on Mr Cool units are that once installed, they work very well.

They are good for the DIY type person that doesn’t want to buy and operate HVAC gauges or vacuum pumps.

For a more experienced DIY type person, there are cheaper kits that, while harder to hook up, cost less.

Read Here for an Overview of All the Mini Split Kits I Have Installed.

I am still testing the unit so far with good results and will update if anything changes.

As always, be sure to read the reviews on Amazon, forums, or elsewhere to be sure a unit is a good fit for you.

Category: Mini split heating and cooling air conditioner heat pump systems

About Aaron H. Benetti

Aaron H. Benetti an HVAC technician who has worked in the field since 1991. He began his career as an HVAC installer and later began doing troubleshooting and repairs. Around 2010, he began to write books on HVAC topics, mainly tutorials and how-to information. Currently, Aaron works as an HVAC tech and also writes many articles and posts for websites as well as books and videos on HVAC topics.

7 thoughts on “Installation and Review: MRCOOL DIY Ductless Mini Split Air Conditioner Heat Pump

  1. Shane

    Mr cool dose not back the products they sell. One of my diy units failed due to a leak in the main unit with the pump within a year. It cost me over a $1000 to get a new one shipped, labor and coolant.
    I regret buying from them.

  2. Arleen

    Where is the filer in the 24000 btu unit with heat unit? Is it easily accessible?

    Do you have a list of service people who service Mr Cool on long island NY….near the 11758 zip code?

    If I were to get an installer to install the unit., what would be a reasonable cost for someone to install it. ( Electric is in already.

    Thank You

    Could you send me your response in my e mail below. Thanks.

  3. Don

    Love the idea of preloaded lines-great for do it yourselfers like me. Would like to know if the main heat pump unit which is depicted as an outside unit could be placed in my basement (full heigt concrete poured foundation).
    I have a drain in the plumbing there and would be great to heat partially finished office in the basement within the limits of the length of the connections.

    1. Aaron Benetti Post author

      Mini split units can be setup in basements and heat pumps both heat and cool. The outside condenser will need to be outside and the line set run to the inside unit. If you have a drain already that is good. If not there is condensation pumps that are hooked up in basements installs that will pump the water condensate up out of the basement. Here is more about condensation pumps.

  4. Walter Greene

    Where are the components of this product made? Where is it assembled?


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