Ductless Mini-Split Heat Pumps 101: Are They Worth It?


Homeowners are increasingly more concerned with energy efficiency when it comes to heating and cooling their homes. When it comes to heating and cooling open spaces, efficiency apartments, additions, etc there is an increasing curiosity for ductless mini-split heat pump systems and whether or not they are a good investment.

Ductless mini-split heat pumps are the most cost-efficient and energy-efficient method for heating and cooling open spaces. Ductless mini-split heat pumps are also very universal, particularly where ductwork is either not present or cannot be installed. These benefits make ductless heat pump systems a great investment.

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However, there are two main factors that need to be considered before any investment in a ductless mini-split heat pump is made. According to the Rise YouTube channel, these two factors include the current energy-efficiency of the house and layout of the house. 

If you live in an older home that is not well insulated, your first order of business should be to add additional insulation into your home particularly in the attic. This will help maximize the energy efficiency of the mini-split heat pump system.

Second, these systems need open spaces in order to be effective. Because they do not use ductwork to distribute air into the room, they are most effective in open spaces where air can flow freely. 

These systems are not suited well in spaces where there are numerous interior walls forming rooms and hallways. We will talk in more detail later in the article about which spaces are ideally suited for ductless mini heat pump systems.

So, without further ado let’s get started. 

What is a Ductless Mini-Split Heat Pump 

To begin with let’s give a layman’s exclamation of what a ductless mini heat pump system is and how it works. 

Ductless mini heat pumps have two main components; an inside unit (often either a wall-mounted unit or an in-ceiling unit called a cassette) and an outside unit. Much like traditional heat pumps, ductless units use refrigerant, like R410a, to transfer heat. 

The inside unit contains a heat exchanger coil, a check valve, and a small fan which is used to push the air across the heat exchanger coil and out the front of the indoor unit. 

The outside unit contains a compressor, heat exchanger coil, large fan, check valve, and a reversing valve. The reversing valve works to change the directional flow of refrigerant in the system to provide heating or cooling.

The main difference between this system and a standard air source heat pump system is the presence of duct work. The components, while they may look different, work exactly the same.

In a standard air-source heat pump, the conditioned air travels through the main supply duct which has branch ducts to individual rooms. A ductless mini-split system does not have ducts. There is a vent in the front of the indoor unit where conditioned air is distributed.

How Ductless Mini-Split Heat Pumps Work

In cooling mode, the indoor unit acts as the evaporator and the outside unit acts as a condenser. The refrigerant passing through the outside heat exchanger coil is hotter than the outside air. The outside air cools the refrigerant before it enters the compressor. The greater the difference in the outside temperature and the refrigerant the greater the heat exchange would be.

The compressor condenses the refrigerant to a cold liquid. As this cold liquid passes through the inside heat exchanger, the fan blows warmer inside air across the cold heat exchanger where the air is cooled and distributed out the front vent of the inside unit.

This exchange process warms the refrigerant as it leaves the inside heat exchanger before heading back to the outside unit where the process repeats itself.

We mentioned before about the reversing valve, well in heat mode, this above process is reversed and the inside unit acts as the condenser and the outside unit acts as the evaporator.

The inside unit is mounted on the wall inside the room. The outside unit sits outside on either a concrete pad or platform. The two units are connected to each other through two refrigerant lines the connect to the heat exchangers. 

Much like standard air-source heat pumps, these units have a refrigerant that travels back and forth between the units. 

Wondering if a new heat pump will add value to your home, check out our article Will a Heat Pump Add Value to Your Home?

Single vs Multi-Zone

Ductless mini-split heat pumps are great for use in open spaces where air can move freely. Many newer homes, townhomes, and condos have open concept floor plans which makes them an excellent choice.

Depending on the layout, ductless mini-split heat pumps can even be used as an auxiliary system in a home or even as a whole-house option.

For instance, as an auxiliary system, if you have an addition or a finished space over a garage and you don’t want to upgrade your entire HVAC system a ductless heat pump is an excellent choice.

As a whole-house option, depending on the layout, a multi-zone ductless system can allow for affordable whole-house heating and cooling. I recently inspected a 2 story home that has an open kitchen/living room concept, downstairs bedroom, and a master bedroom upstairs. The whole house was heated and cooled by a 3 indoor unit multi-zone heat pump system.

A multi-zone ductless system will usually have a maximum of 4 indoor units. As a whole-house option, the maximum square footage covered is about 1500 square feet. When planning a multi-zone configuration, you need to know the total square footage and the square footage of each room and the BTU rating for each unit in the system.

Typical sizing of a ductless heat pump system is as follows (this is only an estimate and does not represent your exact situation):

Area To Be Cooled Capacity Needed (BTUs Per Hour)
150 to 250 square feet 6,000 BTUs
250 to 300 square feet 7,000 BTUs
300 to 350 square feet 8,000 BTUs
350 to 400 square feet 9,000 BTUs
400 to 450 square feet 10,000 BTUs
450 to 550 square feet 12,000 BTUs
550 to 700 square feet 14,000 BTUs
700 to 1,000 square feet 18,000 BTUs
1,000 to 1,200 square feet 21,000 BTUs
1,200 to 1,400 square feet 23,000 BTUs
Up to 1,500 square feet 24,000 BTUs

Insider Tip: When sizing for a mini-split heat pump, you should add 20% to the BTUs if you have ceiling heights over 8 feet or live in a poorly insulated house. You should add 30% to the BTUs if you live in a climate that has seasonal temperatures over 90 degrees F. 1

Best Uses for Ductless Mini-Split Heat Pumps

Ductless mini-split heat pumps work best in open spaces. As you can see above, the 9000 BTU inside unit can heat/cool approximately 350-400 square feet. This is open space, meaning no walls dividing the space. Air should be able to move freely in the space. Examples of areas where these systems are best used include: 

  • Small homes – single-family or multi-family homes and townhomes with 4 rooms or fewer that are less than 1500 square feet. For example, a single-family home or multi-family building where each unit has 2 bedrooms, living room, kitchen are ideal candidates for a multi-zone setup.
  • Apartments/condos – apartments and condos with 4 rooms or fewer that are less than 1500 square feet. Same example, an apartment or condo with 1 or 2 bedrooms, living room, kitchen are ideal candidates for a multi-zone setup.
  • Finished basements – Basements generally have an open floor plan. A single-zone or multi-zone system is ideal because space is generally less than 1500 square feet and may be difficult to install traditional ductwork.
  • Portable buildings – Portable office buildings for job sites or mobile classrooms are ideal candidates for ductless systems. These buildings are generally under 1000 square feet.
  • Commercial buildings – Commercial buildings and offices including salons, restaurants, small retail stores, etc are good candidates due to their open spaces. Older commercial buildings may be difficult to install ductwork due to building configuration without expensive renovations.
  • Sheds – Have a she-shed or man-cave? Using a shed as a workshop or art studio? Sheds are ideal for these systems as they can be run only for the time being used.
  • Garages – Spend a lot of time in your garage working on your car, truck, or motorcycle? Installing a ducted heat pump is against building code as it can allow carbon monoxide poisoning back into the house. Ductless systems eliminate this problem and can keep you cool while you work.
  • Bonus rooms – Bonus rooms are generally located over an existing garage. Oftentimes, single-story homes are built with an option for a room over the garage to be completed at a later date. Installing a ductless system allows you to finish this space without altering the existing HVAC system.
  • Pool houses – Pool houses are great additions to a swimming pool by providing a recreational place to hang out without tracking back inside your house. Pool houses often have an indoor bathroom, living space, and kitchenette making them ideal for a ductless heat pump installation because you can control the ductless heat pump system as you wish.
  • In-law suites – As parents age, many families are opting for additions to existing houses referred to as In-law Suites to care for visiting parents, or live-in parents. These additions usually consist of a private living area, bedroom, and bathroom and are usually well within the 1500 square feet limit.

If you are installing a standby generator and wondering if it will power a ductless heat pump see our article Will a Generator Run Your Heat Pump?

Popular Features of Ductless Heat Pumps

Superior Energy Efficient – Ductless heat pump designs provide increased efficiency over standard air-source heat pumps due to their ductless design. Standard heat pump designs can lose as much as 30% of the heated and cooled air produced through cracks on the ductwork. If the ductwork is older with damaged insulation around the pipes you can lose nearly all of the heated and cooled air produced. 2

Remote operation – Ductless systems have a remote control that doubles as an in-room thermostat. The system can be controlled by the remote or the remote can be programmed like a thermostat to function at specific times and room temperature.

Smartphone integration – Many systems have smartphone integration allowing you to control the system from a smartphone. Want to turn your system on from your office or car while on the go? At work and realize you forget to turn your system off? No problem. With remote access through WIFI or Data, you can control your system from anywhere.

No air ducts/better air quality – Because of its ductless design, there are no ducts to collect airborne particles such as allergens and mold spores. This improves your air quality. Ductless systems also have a washable reuseable air filter located in the inside unit.

Quiet to use – Ductless units are very quiet to use compared to other appliances. Ductless units average about 32 decibels, which is lower than a dishwasher which normally operates at 46-60 decibels. Window AC units on low-speed average about 43 decibels. They are even quieter than an oscillating fan which runs at about 38-50 decibels.

Independent Comfort Settings – Ductless heat pumps put the control at your fingertips. You can control zones independently, which gives you better control to suit your needs. For example, in a standard heat pump, the thermostat controls a single temperature over a wide area which can create hot and cold spots. Ductless systems allow you to control room temperature more evenly.

Lower installation cost – Installation costs of a multi-zone ductless heat pump and standard heat pump can be approximately the same when just the equipment is concerned where existing ductwork is present. However, where ductwork is not present or duct replacement is needed, a significant saving exists. According to Homeguide.com, new ductwork can cost $35 to $55 per linear foot. 3

Installation flexibility – The positioning of a ductless system offers flexibility in that the indoor unit can be mounted at various positions and only requires a 3-inch hole in the wall to run the refrigerant lines to the outdoor unit. The outside unit can be installed up to 50 feet from the inside unit.

The typical outside unit weighs approximately 155lbs and is only about 38x31x16 inches in size. This compact and lightweight design allow for the outside unit to be installed on an elevated platform for installations on the second story or higher installations.

DIY Installation optionDuctless mini-split heat pumps allow for a DIY installation with a few skills and some general know-how. The installation of a ductless heat pump system is relatively easy and straight forward.

However, the hardest portion of the installation is the required electrical work. The electrical work needed includes:

  • A 220v double breaker installed in the main panel.
  • A service discount box at the outside unit.
  • Wiring from the breaker to the service disconnect.
  • Wiring from the service disconnect to the outside unit.

If you are comfortable working with electricity, then you can easily handle this DIY job. However, if not, you are better off hiring a professional to do the installation.

According to PickHVAC.com, the total potential installation labor savings are up to $2,700 if you do the entire install yourself including the electrical work. If you hire a licensed electrician you can expect to spend about $850 – $1400 to do the electrical work. This leaves an approximate savings of $450 to $1,100 with an average savings of $675. 4

Popular Ductless Mini-Split Heat Pumps

Best Ductless Heat Pump Brands

Samsung Ductless Mini-Split Heat Pumps

Samsung offers several models of single and multi-zone ductless heat pumps ranging from 7,000BTU to 36,000BTUs. One of the most popular models is the Smart Whisperer Max Heat®. Some of the unique features of this Samsung ductless mini-split heat pumps include:

  • The Smart Whisperer Max Heat® system is an Energy Star® certified cold climate air source ductless heat pump that is ideal for temperatures as low 5 degrees F down to as low as -13 degrees F. This makes this system ideal for installation in climates that experience all four seasons, including subfreezing temperatures during the winter months.
  • Features a triangular design air intake that allows for more fresh air intake. This allows the unit to draw in more air with a larger fan than competitor models which allows for better air distribution.
  • Has built-in Wi-Fi allowing you the freedom to control the unit from just about anywhere through the SmartThings App.  As long as you have WIFI remote access you have control over this system.
  • The Digital Inverter compressor features variable speed control that allows the compressor to automatically adjust to maintain the desired set temperature automatically.
  • The Smart Install is a self-diagnosis feature that checks for installation errors such as miscommunication with the outdoor unit, poor refrigerant flow, and other system points. This makes DIY install of this system a breeze.
  • Features a twin BLDC compressor for high performance, and low noise and vibration.
  • Features a 10-year warranty on the compressor & parts and a 1-year limited labor warranty.
  • Single zone and multi-zone configuration available.

Samsung ductless heat pump systems are sold by Certified Dealers. You can search for a certified dealer near you at Samsung HVAC Locater.

Carrier Ductless Mini-Split Heat Pumps

The Carrier Performance Series ductless heat pump system offers a single or multi-zone setup. This ductless system will perform at 100% heating capacity at 5 degrees F.

So, while it may not be suitable for cold northern climates that experience routine sub-zero temperatures, it is very suitable for more moderate climates.

Some of the features include:

  • Very efficient 23.8 SEER cooling efficiency rating and up to 10.5 HSPF heating efficiency. Making this one of the more efficient models on the market.
  • Features a variable-speed digital inverter compressor that automatically adjusts to maintain the desired set temperature.
  • The indoor unit has 4 fan speeds with turbo mode setting for quick temperature adjustment to quickly reach your desired set temperature.
  • Quiet indoor operation as low as 27 decibels
  • As of this writing, it has a 4/5 star rating on the Carrier website.
  • Connects two to five multiple style indoor units (Performance™) off a single outdoor unit
  • 10-year parts limited and 10-year compressor limited warranties.

Mitsubishi Ductless Mini-Split Heat Pumps

Mitsubishi is a market leader in ductless mini-split heat pumps and features both single-zone A/C and heat pumps and multi-zone heat pumps. Mitsubishi features advanced technology making them a top choice for your heating and cooling needs.

Mitsubishi ductless mini-split heat pumps operate at 100% capacity in extreme cold down to 15 degrees F. Multi-zone systems feature patented Hyper-Heat technology which provides efficient warmth, even in extreme climates.

  • Very efficient 26 SEER cooling efficiency rating and up to 10.5 HSPF heating efficiency. Making this one of the best models available.
  • Inverter driven compressors automatically adjust compression to maintain the desired set temperature and energy-efficiency for optimal daily operation.
  • Connects up to five multiple mix and match style indoor units off a single outdoor unit.
  • 3D I-See Sensor technology helps to provide precise desired temperature by scanning the room and adjusting the output accordingly.
  • Instant Hot Start prevents cold air starts by providing instant warm air on startup.
  • Features auto-restart following a power outage.
  • Kumo cloud wireless controls allow wireless operation through an app on your tablet or smartphone.
  • 5-year parts limited and 7-year compressor limited warranties.

Mitsubishi ductless mini-split heat pumps are sold by Certified Dealers. You can search for a certified dealer near you at Mitsubishi Dealer Locater.

Daikin Ductless Mini-Split Heat Pumps

Daikin manufactures both single-zone and multi-zone ductless heat pump systems. The DAIKIN Dual (2 Zone) Air Conditioner Heat Pump + Maxwell 15 ft. Installation Kit + Wall Bracket (9000 + 12000 BTU) is available at Amazon. This model is a 2 zone system with 2 indoor wall-mounted units to distribute air through the home.

Some of the features of Diakin ductless heat pumps include:

  • The above model offers an 18.9 SEER cooling efficiency rating and a 10.7 HSPF heating efficiency. Cooling and heating efficiency varies depending on the models.
  • Offers a variety of interior unit designs including wall-mounted, ceiling cassettes, among other options. The above model offers wall-mounted indoor units.
  • Remote control operation with programmable settings. Wifi capabilities are not included but are an additional option.
  • 12 years parts warranty available provided the system is installed by a professional HVAC contractor.

Fujitsu Ductless Mini-Split Heat Pumps

Fujitsu manufactures several models of single-zone ductless heat pumps including Fujitsu 15,000 Btu 25.3 Seer Single Zone Ductless Mini Split Heat Pump System available at Amazon. This model consists of an outdoor condenser and one indoor unit to distribute air through the home.

Some of the features of Fujitsu ductless heat pumps include:

  • Compact design and install flexibility is a trademark of these systems. With a slim outside unit design and a wall-mounted indoor unit,
  • The above model offers a 25.3 SEER cooling efficiency rating. Cooling efficiency varies depending on the models.
  • Fujitsu ductless heat pumps offer a variety of interior unit designs including wall-mounted, ceiling cassettes, among other options. The above model offers a wall-mounted indoor unit.
  • includes a long-life ion deodorizing filters that remove odors and dust, and other harmful airborne contaminants. Filters are washable and reusable.
  • Remote control operation with programmable settings. Wifi capabilities are not included but are an additional option.
  • Warranties are available provided the system is installed by a professional HVAC contractor.
  • Multi-zone setups are available. Consult with your professional HVAC contractor for setup options.

Additional Ductless Heat Pump Systems

Toshiba Carrier Ductless Mini-Split Heat Pumps

Made by Carrier, the Toshiba Carrier Highwall ductless heat pump system is the perfect single-zone setup ductless system. This ductless system will perform when outdoor temperatures are as low as 14 degrees F and as low as 5 degrees F.

So, while it may not be suitable for cold northern climates that experience routine sub-zero temperatures, it is very suitable for more moderate climates.

Some of the features include:

  • Very efficient 23 SEER cooling efficiency rating and up to 10.0 HSPF heating efficiency. Making this one of the more efficient models on the market.
  • Features a variable-speed digital inverter compressor that automatically adjusts to maintain the desired set temperature.
  • The indoor unit has 5 fan speeds with turbo mode setting for quick temperature adjustment to quickly reach your desired set temperature.
  • Quiet indoor operation as low as 26 decibels
  • 5-year parts limited and 7-year compressor limited warranties.
  • As of this writing, it has a 4/5 star rating on the Carrier website.

LG Ductless Mini-Split Heat Pumps

LG manufactures both single-zone and multi-zone ductless heat pump systems. The LG 2.5 TON 30000 BTU SEER 20 Dual Zone 12K + 18K BTU Heat and Cool Mini Split AC Heat Pump System Energy Star with Built in WiFi is available at Amazon. This model is a 2 zone system with 2 indoor wall-mounted units to distribute air through the home.

Some of the features of LG ductless heat pumps include:

  • The above model offers a 20 SEER cooling efficiency rating. Cooling efficiency varies depending on the models. Energy Star rated.
  • Offers a variety of interior unit designs including wall-mounted, ceiling cassettes, among other options. The above model offers wall-mounted indoor units.
  • Remote control operation with programmable settings. Built-In WiFi for remote operation from anywhere you have a WiFi signal.
  • 7-year parts warranty and 5-year compressor warranty provided the system is installed by a professional HVAC contractor.
  • Inverter driven compressors automatically adjust compression to maintain the desired set temperature and energy-efficiency for optimal daily operation.
  • 100% heat operation down to as low as 14 degrees F
  • Jet Cool/Jet Heat: Operates at high speed for up to 30 minutes to quickly cool a room down to 64 degrees F.

Gree Ductless Mini-Split Heat Pumps

Gree manufactures both single-zone and multi-zone ductless heat pump systems. The Gree MULTI30CVIR402-30,000 BTU Multi21+ Quad-Zone Wall Mount Mini Split Air Conditioner Heat Pump is available at Amazon. This model is a 4 zone system with 4 indoor wall-mounted units.

Some of the features of Gree ductless heat pumps include:

  • The above model offers a 21 SEER cooling efficiency rating. Cooling efficiency varies depending on the models. Energy Star rated.
  • Remote control operation with programmable settings. Wi-Fi Capable – Kit Sold Separately.
  • Inverter driven compressors automatically adjust compression to maintain the desired set temperature and energy-efficiency for optimal daily operation.

Pioneer Ductless Mini-Split Heat Pumps

Pioneer manufactures single-zone ductless heat pump systems. The PIONEER Air Conditioner Pioneer Mini Split Heat Pump Minisplit Inverter is available at Amazon.

Some of the features of Pioneer ductless heat pumps include:

  • The above model offers a 22.5 SEER cooling efficiency rating and a 10.5 HSPF heating efficiency. Cooling and heating efficiency varies depending on the models.
  • Remote control operation with programmable settings.
  • Inverter driven compressors automatically adjust compression to maintain the desired set temperature and energy-efficiency for optimal daily operation.
  • Arctic heating version with base pan heaters. Heats down to -12 degrees F ambient.
  • Low-cost systems are an affordable DIY option. Some tools will be required.

DIY Mini-Split Heat Pump System

MrCool Ductless Mini-Split Heat Pumps

MrCool is designed with the DIY installer in mind. It is the only true DIY ductless mini-split heat pump on the market. Other systems can be DIY but require special tools. The MRCOOL Comfort Made Simple MRCOOL DIY 18,000 BTU Ductless Mini Split Air Conditioner and Heat Pump System with Wireless-Enabled Smart Controller is available at Amazon. The MrCool ductless heat pump has features comparable to more well-known brands.

Some of the features of MrCool ductless heat pumps include:

  • Control your system through the SmartHVAC app. It is also compatible with Alexa and Google Assistant. Control with your tablet or smartphone from anywhere there’s a WiFi connection.
  • Auto-restart: System will automatically restart in the event of a power outage.
  • Easy DIY installation: 25ft quick connect line doesn’t require special tools, equipment, or training. The unit is factory pre-charged with R-410a refrigerant which eliminates the need for an HVAC technician to charge your system.
  • Gold fin condenser that is corrosion-resistant and stands up to coastal weather.
  • Variable-speed DC inverter compressor adjusts automatically to meet and maintain the desired temperature.
  • Leak detection feature alerts you if the is a leak in the system to prevent damage to the compressor.

For more on ductless heat pumps see our article Best Uses For Ductless Heat Pumps

Finally, our Complete Guide to Heat Pump SEER Ratings is your complete resource for information on SEER ratings.

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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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