What is a Ductless Mini-Split Air Conditioner?


Ductless mini-split air conditioners or heat pumps are an increasingly popular HVAC choice for homeowners around the world, and for good reason. These versatile systems offer both heating and cooling capabilities, making them a practical solution for year-round comfort. But what exactly is a ductless mini-split air conditioner, and how does it work? Let’s dive in to understand this innovative technology better.

Table of Contents

How Ductless Mini-Split Air Conditioners Work

A ductless mini-split air conditioner or heat pump extracts heat from the outside air and brings it inside during the winter, and reverses the process to cool your home in the summer. In cooling mode, the system absorbs heat from your indoor air and releases it outside. In heating mode, it extracts heat from the outdoor air — even when it's cold — and transfers it indoors.

This is achieved through a refrigeration cycle involving 3 key components: a compressor, a condenser, and an evaporator

Mini split heat pump diagram

Components of a Ductless Mini-Split Air Conditioner or Heat Pump

Ductless mini-split air conditioners or heat pumps are made up of an outdoor unit and an indoor unit.

Outdoor Unit

  • Compressor: The compressor is the heart of the ductless mini-split, as it pumps refrigerant through the entire system. This refrigerant absorbs heat from one location and releases it in another. The refrigerant is compressed, which raises its temperature and pressure, and enables it to move through the system.
  • Condenser Coil: This coil releases heat to the outside air during cooling mode and absorbs heat from the air during heating mode.
  • Fan: The fan assists in dispersing heat outside during cooling and extracting heat from the outside air during heating.
  • Electrical Circuit: The electrical circuit manages the power supply to various components of the unit, including the compressor, fan motor, and control board. It also handles communication with the indoor unit, often through low-voltage control wires, ensuring synchronized operation.
  • Motor: The motor in the outdoor unit primarily drives the fan, which is crucial for dissipating heat absorbed from the indoor environment. This fan helps move air across the condenser coil, facilitating the release of heat during the cooling cycle or absorption of heat during the heating cycle.

Indoor Unit

  • Evaporator Coil: The evaporator coil absorbs heat from the indoor air in cooling mode and releases heat into the air in heating mode.
  • Fan: This fan circulates the conditioned air throughout the room, ensuring even temperature distribution.
  • Temperature Sensor: The temperature sensor monitors the temperature of the room air and/or the evaporator coil, ensuring that the system maintains the desired room temperature by providing feedback to the control system.
  • Electrical Circuit: The electrical circuit distributes power to and handles communication between various components of the system, including the control board, temperature sensors, fan motor, and other electronic parts.
  • Motor: The motor powers the fan that circulates air across the evaporator coil and into the living space, ensuring that the conditioned air is evenly distributed throughout the room.
  • Filter: The filter is crucial for maintaining indoor air quality and ensuring the efficient operation of the system. It traps dust, pollen, pet dander, and other airborne particles as air passes through the unit. Regular maintenance and replacement of the filter are necessary to prevent clogging, which can reduce airflow, decrease efficiency, and put additional strain on the system.

Refrigerant Lines

  • Conduit: The conduit connects the outdoor and indoor units. It contains power cables, refrigerant tubing, suction tubing, and a condensate drain, facilitating the seamless transfer of refrigerant and condensate between units.

Control Systems

Man controlling mini split ac on his phone

What are the Advantages of a Ductless Mini-Split Air Conditioner or Heat Pump?

Among the many heating and cooling systems available, ductless mini-splits stand out for their versatility and efficiency. Whether you're looking to save on energy costs, improve comfort, or reduce your environmental footprint, installing a ductless mini-split can be a game-changer. Let's explore the many benefits of ductless mini-splits.

Energy Efficiency

One of the most compelling reasons to install a ductless mini-split air conditioner is its exceptional energy efficiency.

Cost Savings

Ductless mini-splits are designed to consume less energy compared to traditional HVAC systems. This efficiency translates into significant cost savings on your utility bills. Additionally, many regions offer rebates and incentives for installing energy-efficient HVAC systems, making it even more affordable.

Environmentally Friendly

Using less energy not only saves money but also reduces your carbon footprint. Ductless mini-splits use eco-friendly refrigerants and have a lower impact on the environment compared to older systems that rely on fossil fuels.

No Ductwork Required

Traditional HVAC systems lose a significant amount of energy through ductwork. Ductless mini-split systems eliminate this issue by delivering air directly to the rooms where it's needed, resulting in higher efficiency and lower energy loss.

Mini-split heat pump installed in home

More Comfortable Spaces

Beyond energy efficiency, ductless mini-split air conditioners enhance the comfort of your living spaces.

Heating and Cooling in One System

A ductless mini-split provides both heating and cooling, offering a year-round solution for maintaining a comfortable indoor environment.

Zoned Heating and Cooling

One of the standout features of ductless mini-splits is their ability to provide zoned heating and cooling. By placing multiple mini-splits throughout your home, you can control the temperature in individual rooms or areas, tailoring comfort to your specific needs and preferences.

Improved Indoor Air Quality

With advanced filtration systems, ductless mini-split air conditioners help improve indoor air quality by reducing pollutants, allergens, and dust. This is especially beneficial for individuals with respiratory issues or allergies.

Mother and son enjoying mini split

Easy Installation

Another advantage of ductless mini-split air conditioners or heat pumps is their relative ease of installation when compared to installing other electrical heating and cooling systems.

Less Invasive

Ductless mini-split air conditioners or heat pumps require only a small hole for the conduit, making them less invasive than traditional systems that need extensive ductwork installation. This minimal disruption is ideal for both new constructions and retrofits in existing homes.

Flexible Placement

The indoor units of mini-split systems can be mounted in various locations such as walls, ceilings, or floors, providing flexibility in design and placement to suit your space.

DIY or Find a Local Expert

Many handy homeowners take on installing their own mini-splits. However, we generally recommend getting some professional help. There are many qualified contractors experienced in installing mini-split systems that can take care of everything in one day.

Man installing a mini-split heat pump

Smart Thermostats for Ductless Mini-Splits

While most mini-split systems come with a remote control, integrating a smart thermostat or controller like the Mysa for Mini-Split Heat Pumps and AC can offer more convenient, easy control. The Mysa app allows you to manage your ductless mini-split air conditioner from anywhere, set schedules, and optimize ductless mini-split air conditioner energy use more effectively than standard remotes.

Do I Need a Ductless Mini-Split Air Conditioner or Heat Pump?

While the benefits of ductless mini-splits are obvious, they’re not the right fit for every home. For example, homes with an existing central HVAC system with ductwork may not notice significant energy savings, making the cost and effort of installing a ductless mini-split air conditioner not worth it. 

However, ductless mini-split air conditioners are the ideal HVAC solution in many situations:

Ductless Homes

Ductless mini-splits are perfect for homes without existing ductwork, such as older buildings or newly constructed additions. They provide an efficient way to control the indoor climate without the need for extensive (and expensive) duct installation.


For older homes or buildings, retrofitting with a ductless mini-split air conditioner can significantly improve energy efficiency and comfort without the need for major renovations.

Detached Buildings

Whether it’s a detached garage, a studio, a shed, or any other separate space from your main home, a ductless mini-split air conditioner can offer targeted heating and cooling.

by LastSale
by LastSale