How Does a Split Air Conditioner Work?

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A split air conditioner is a suitable alternative to wall, window, or centralized air conditioner systems. Often called mini-split, ductless split, or duct-free air conditioning, this system can adequately cool a standard-sized house without requiring extensive installation costs and efforts.

Split air conditioners are home appliances that do not require ductwork, which reduces energy expenditures. Still, many homeowners shy away from a split air conditioner system because they do not know how it works or why it is a viable option for cooling down.

The following information will fill you in on the function and installation of split air conditioner systems. They are uncommon, but not through any fault or flaw. You may discover that a split system sounds ideal for your own home needs.


A split air conditioner is made up of two primary parts that a very familiar: the evaporator and the compressor. Both of these elements exist is more common central air units and wall air conditioners. The difference with a mini-split system is that they are separated into two different, distant components, one being outdoors and one being indoors. The outdoor section is a compressor that initiates the cooling process, while the indoor component consists of an evaporator and fan.

The two sections are connected with a set of electrical wires and tubing, also called lines, used to transport air between the two sections. It's these lines that allow the split AC to be considered ductless, and the fact that the wires and tubing are so small and discreet compared to large ducts is where the "mini" split name comes from.


The compressor is controlled by an internal thermostat. As the thermostat detects warm air, it activates the outdoor compressor. The compressor circulates a refrigerant gas, increasing the pressure and temperature of the refrigerant as it compresses it through a series of pipes. The refrigerant then moves to the condenser for further processing.

In the condenser, a cooling system removes heat from the high-pressure gas and the gas changes phase and becomes a liquid. This chilled liquid is pushed through tubing indoors until it reaches the evaporator system.

Inside the home, the evaporator fan collects warm air and passes it through a chamber containing the chilled liquid refrigerant. The fan system blows this air, which has now been cooled, back into the room, lowering the overall temperature of the space. If the thermostat still detects air that is warmer than desirable, the process continues, and the refrigerant and any excess heat that remains in the system are passed back outdoors to the compressor in order to begin the cycle again.

Benefits of Split Air Systems

Less Energy Loss

A Split air conditioner is compact and isolated between two localized component sections, so there is very little opportunity for heat and other energy to escape the system. Centralized air conditioning systems waste enormous amounts of energy due to heat exchange in the air conditioner duct system. However, this problem is virtually eliminated in a split air conditioner system.

Less Heat Loss

Split air conditioner systems are preferable to window and wall air conditioning units as well. Although the latter are small and easy to install, they do not provide reliable cooling to a large space or to multiple rooms. Even with thoroughly sealed windows and walls, these air conditioner units allow for heat to enter the space, partially negating the effects of the system.

Targeted Heating and Cooling

Additionally, it's possible to have more than one indoor evaporator and fan. You could have one in each room or area of your home and run them each independently with only one outdoor compressor. This combines the efficiency and customization of a space heater or fan with the convenience of central air.

Affordable Installation

Split air conditioners are compact, easy to operate and maintain, and relatively inexpensive. They do require some electrical wiring and other specialized installation techniques, so it is advisable to hire a professional air conditioner installer to set up the system. However, once the system is installed, most homeowners find that it is a cheap, energy-efficient way of adequately controlling the heat within the home.