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How Does A Mini Split Work?

how does a ductless mini split work

Mini splits offer many advantages over traditional ducted AC systems that make them worth considering. They are quieter, more efficient, and more flexible than forced air systems that need ductwork.

If you’re wondering how mini splits function and what makes them different, then this article is for you. In this guide, we discuss how ductless mini splits work, as well as explore the functions of inverter mini splits, mini split heat pumps, and single and multi-zone units.

What is a Mini-Split?

In a nutshell, a mini-split AC unit does the same thing as a traditional AC unit: it cools your home. The big difference between the two is that mini split air conditioners manage to do so without ducts, which is why they are also called ductless air conditioners.

A mini split consists of two units: an indoor unit and an outdoor unit. The indoor unit houses the air handler, while the outdoor unit hosts the compressor. Both are connected by a conduit that houses the refrigerant line, communications wire and power.

To know more, check out our related article: The Components of a Mini Split AC System.

How Does a Mini-Split Work?

We’ve heard plenty of advantages of using a ductless mini split, but first it’s important to know how a mini split actually works. 

The indoor unit blows the warm air from your home over cold evaporator coils. Inside the coils is refrigerant, which absorbs that heat from the air, and runs it to the outside unit that houses the compressor. The compressor dumps the heat pulled from the indoor air to the outside. The resulting cold air is then circulated back into the room.

how mini splits work

This system differs significantly from a conventional central air conditioner, which usually works with one air handler, evaporator coil, and blower. A conventional ducted AC system works by using ductwork to deliver air into each room of a building from a single point of origin.

In contrast, a ductless mini split works by using only a small 3-inch conduit to connect the indoor air handler with the outdoor unit that houses the compressor.

To know more about the pros and cons of each type of system, check out Mini Split vs Central Air/Heat: Which is Right for You?

How Does a Mini-Split Heat Pump Work?

A mini split heat pump is one that offers both cooling and heating capabilities. It does this by using a heat pump and reversing the flow of the refrigerant.

In heating mode, the heat pump pulls in heat from the outside and transfers it inside via the refrigerant. The indoor air handler then distributes the warmed air into the room.

Mini split heat pumps are highly efficient, drawing only 50% of the energy required by a typical central air system. A mini-split heat pump may be all you need for both cooling and heating. 

Click here to know more about mini split heat pumps.

Advantages of Using a Mini Split

Mini-split units are growing in popularity for a variety of reasons, but some of the most common advantages cited are their efficiency and quiet operation.

Because mini-splits are ductless machines, they reduce a large amount of energy that is often lost through leaks and cracks in duct systems. According to the US Department of Energy, ductwork accounts for up to 30% of heat loss in a traditional ducted AC system. By eliminating the duct, mini splits are more energy efficient, and this translates to utility bills.

For this same reason, mini splits work much more quietly since they are not blowing air through ducts all over a room or home.

Compared to window air conditioners, mini splits have high EER and SEER ratings, which measure the efficiency of AC units. Theyare also equipped with inverter technology, which dynamically adjusts the unit’s power draw based on demand for even more efficient operation. 

Read our in-depth discussion on the efficiency of mini splits and why they are a better investment than conventional AC systems.

How Do Single and Multi-Zone Mini Splits Work?

Areas or rooms that need to be cooled can be divided into “zones”. As such, a single-zone mini split is one designed to cool a single zone or room, while a multi-zone mini-split can handle several rooms. 

Multi-zone mini splits can be further classified into dual-zone, trizone, quadzone or even five-zone systems, which denote how many spaces they can handle.

Here is a breakdown of each system to help you decide which one you should purchase for your home:

Single Zone Mini Splits

  • How this mini-split works: These include one outdoor and one indoor unit, where the indoor unit is placed in the particular room you want to cool or heat individually. It can also be used in one total area in your home rather than just one room.
  • These systems are particularly great if you only want to cool and heat one specific room like an attic, garage, or addition. They are also great when you don’t want to mess with existing ductwork.

Multi-Zone Mini Splits

  • How this mini-split works: In a multi-zone system, several indoor units all hook up to a single outdoor unit. The number of indoor units depends on the number of spaces you want to cool, but they all connect back to one compressor outdoors.
  • As the name suggests, this system can occupy several different rooms or areas within a home. This is great for cooling and heating several rooms with different temperatures to accommodate each family members’ temperature preferences. Multi-zone mini splits are also great for avoiding ductwork.

Overall, your decision to just heat or cool one or multiple rooms in your house will be the answer to which mini-split system you’ll need. Also, depending on the size of your cooling needs (which you can calculate and compare here), figuring this out may help in making your decision as well.

How Does a Mini Split Inverter Work?

An inverter is a device that can change the variable speed of the compressor. A mini split inverter works by adjusting the compressor’s rotation speed dynamically. Instead of operating at 100% all the time, it can throttle down the compressor once the desired temperature is reached. 

This allows the mini split to be much more efficient and quieter compared to non-inverter equipped mini splits. To know more, check out our Guide to Mini Split Inverters and how much more efficient they can be.

Single-Zone and Multi-Zone Products to Check Out

If you are thinking that a mini-split air conditioner sounds like the perfect fit for you, you are already in the right place to find one. Total Home Supply carries a variety of mini-split units available for purchase.

Entry level single-zone mini split:

Friedrich FSHW121 12000 BTU Floating Air Select Series Single Zone Mini Split – Heat and Cool – 115V

The FSHW121 mini split is a 115 Volt, cooling with heat pump system. It features high efficiency ratings including a 18.0 SEER and 10.1 EER. The built-in low ambient cooling capabilities will cool your space when outside temperatures are as low as 0°F. The 13,000 BTU heat pump will work hard to keep you warm.

This system cannot be used as a primary heating source for most of the country, but it will give you 7,100 BTUs at 17°F with its low ambient heating capacity and can continue to provide heat even with temperatures down to -4°F. If you are need to cool a server room or other equipment year round, this unit’s low ambient cooling features make it a great choice.

The 12,000 BTUs cooling capacity can service a room that is about 450 sq. ft. It comes with inverter technology for more efficient and silent operation, as well as 25 feet of line. Additionally, the line sets can be as long as 66 feet between the compressor and the indoor unit with a 49.2 foot height difference. Line sets are sold separately.

DISCONTINUEDFriedrich FSHW121 12000 BTU, 17.5 SEER2 Floating Air Select Series Single Zone Mini Split - Heat and Cool - 115V
Price: $1,106.00 DISCONTINUEDFriedrich FSHW121 12000 BTU, 17.5 SEER2 Floating Air Select Series Single Zone Mini Split - Heat and Cool - 115V

Friedrich FSHW121 12,000 BTU single zone mini split system includes both the FSHSW12A1A wall unit and the FSHSR12A1A outdoor compressor. Inverter Te...

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Premium single zone mini split

Bosch 12,000 BTU Climate 5000 MAX Performance Single Zone 22.5 SEER Mini Split System

With inverter drive technology, Bosch’s premium Climate 5000 systems are Energy Star Rated. This unit boasts 13.0 EER and 22.5 SEER ratings. It is capable of 12,000 BTUs of cooling and 12,000 BTUs of heat.

It can operate at low ambient temperatures as cold as -22°F, and delivers 100% heating capacity at temperatures as low as -5°F, with no additional hardware or accessories required. It also includes a factory installed base pan heater that keeps the condensate from freezing in extreme conditions. This system will also cool at low temperatures for national usability.

Features include an infrared sensor that detects activity in a room and automatically adjusts the fan speed; and Humidity Control, which allows the system to increase the comfort level by lowering the humidity, not the temperature. It is also equipped with a Self-Cleaning Mode that helps to remove additional particles internally and excess moisture, with blue-fin technology, reducing or eliminating mildew.

DISCONTINUEDBosch 12000 BTU Climate 5000 MAX Performance Single Zone 22.5 SEER Mini Split System - Heating Capabilities to -22°F
Price: $1,399.00 DISCONTINUEDBosch 12000 BTU Climate 5000 MAX Performance Single Zone 22.5 SEER Mini Split System - Heating Capabilities to -22°F

  With inverter drive technology, the Climate 5000 systems are Energy Star Rated. Inverter technology will save you money in the long run, by lowering you...

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Entry level multi zone mini split

Friedrich FPHMR36A3A 32000 BTU Floating Air Pro Quad-Zone Mini Split Air Conditioner with Heat Pump

This 2,000 BTU unit that has a connected capacity of up to 48,000 BTUs. As a quadzone mini split, a minimum of two units must be connected and the minimum combination or units must be at least 50% of the connected capacity, or 24,000 BTUs.

Several indoor units are available for use with the quad zone mini-split system. Any combination of 7,000, 9,000, 12,000, 18,000 and 24,000 BTU units can be used in the installation of the quad zone system. These include Friedrich’s standard wall unit, 4-way ceiling cassette as well as a ceiling concealed duct unit. Each unit works with its own remote (included with wall and ceiling cassettes) or wall controller (included with concealed duct units) allowing for individual comfort control.

Depending on your installations of non ducted, ducted, or mixed units, the FPHMR36A3A gets great energy ratings.

EER SEER HSPF
Non-Ducted Indoor Units Only 12.5 21.0 11.0
Ducted Indoor Units Only 12.0 19.5 10.8
Mixed Non-Ducted and Ducted Indoor Units 12.25 20.25 10.9

It features Friedrich’s Precision Inverter Technology, offering a variable speed compressor to keep up with your comfort control needs while still being energy efficient. The outdoor unit features Low Ambient Operation making it a great year round option for heating and cooling for most of the US. It will operate in the Cooling Mode when outdoor temperatures are as low as 14°F up to 115°F. The range in which this unit will heat is equally as wide and it will heat when temperatures are as low as -13°F up to 75°F!

Friedrich FPHMR36A3A 32000 BTU Floating Air Pro Quad-Zone Mini Split Air Conditioner with Heat Pump
Price: $2,749.00 Friedrich FPHMR36A3A 32000 BTU Floating Air Pro Quad-Zone Mini Split Air Conditioner with Heat Pump

Base Price shown is for outdoor unit only. You can choose 2, 3 or 4 indoor units below with a total connected capacity of 48,000 BTUs.  If you are choosing...

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Premium multi zone mini split

Bosch BMS500-AAM036-1CSXHC MAX Performance 36,000 BTU Configurable Quad-Zone Heat and Cool Split System

Rated at 36,000 BTU cooling capacity, this quad zone system can handle a total connected capacity of up to 48,000 BTUs. The system will adjust its load as needed.

For example, if you connect four 12,000 BTU units, you can run them all simultaneously with the 36,000 BTU condenser. The system will allocate its 36,000 BTUs appropriately for your four spaces. If you are using only one room at any given time, that room will receive the total capacity of the indoor unit.

The MAX Performance condenser features Inverter Drive Technology provides optimum power control and extremely efficient operation by automatically changing the condenser power. The result is speedy, flexible operation that uses less electricity. It constantly adjusts the compressor rotation speed to provide optimum performance at all times. It can operate at low ambient temperatures and delivers 100% heating capacity at temperatures as low as -5°F, with no additional hardware or accessories required. It also includes a factory installed base pan heater that keeps the condensate from freezing in extreme conditions. This system will also cool at low temperatures for national usability.

DISCONTINUEDBosch BMS500-AAM036-1CSXHC MAX Performance 36000 BTU Configurable  Quad-Zone Heat and Cool Split System
Price: $3,859.00 DISCONTINUEDBosch BMS500-AAM036-1CSXHC MAX Performance 36000 BTU Configurable Quad-Zone Heat and Cool Split System

Bosch Climate 5000 Series 36,000 BTU Quad-Zone Outdoor Condenser Unit offers heating and cooling operation range down to -22°F, with 100% capacity at -5&deg...

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Find the Mini Split That’s Right for You

There’s no doubt that mini-split air conditioners and heating units are growing in popularity, as they offer a quieter, more efficient system that does not require the use of ducts to deliver air to different rooms. Depending on your needs, you may find that a single zone multi-split is most appealing, where you can purchase a PTAC or mini split system. Or you can simply opt for a multi-zone setup for your entire home.

Whatever you end up choosing, Total Home Supply has you covered. Check out the mini-split units available on our site, and upgrade your cooling system to ensure comfort in the dog days of summer!

Related Articles

What’s a Mini-Split AC System? – What Is a Mini Split AC?

Mini Split vs Central Air/Heat: Which is Right For You?

What Is a Mini Split Inverter?

Mickey Luongo

Mickey is the resident heating and air conditioning expert with over 15 years of experience in the industry.

8 thoughts on “How Does A Mini Split Work?”

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    […] products are mini split systems, making them extremely efficient. Since LGRED mini splits do not require any sort of ductwork to operate, heat and cold air stay […]

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    […] serious saving. And to top it all off, you’ll end up saving money in the long run since mini split systems are highly efficient compared to central heat and […]

  3. Ductless Mini Split Heat Pumps: Using a Mini Split Heater says:

    […] going into why mini split heating is a great option, let’s take a look at how they work. These systems work by way of heat pumps, or a unit that can change from cooling to heating by […]

  4. Mini Split Cleaning & Maintenance - A How To Guide says:

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  5. If outside air is smoky from forest fires, which system, ductless or central air, will keep the smoke out of the home best?

    1. Mickey Luongo says:

      Neither a mini split or central air system bring in air from outside so they would perform the same from that aspect.

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