How Does an Air Conditioner Work?

Many people often wonder about AC units and how they cool the area. It’s a valid question that can be confusing if you don’t understand the process. So, how do air conditioners work?

How does air conditioning work? The process

In a nutshell, air conditioners absorb and remove the heat, transferring it outside through a refrigerant housed inside protective coils. These coils move the refrigerant back and forth from inside to outside. AC units have four main parts: the evaporator, compressor, expansion valve, and condenser. These parts work together, manipulating the refrigerant to absorb or reject heat when needed.

Consider the unit an appliance, like the refrigerator. While a refrigerator has a box to keep items cold, your home acts as a box to keep the temperature regulated. The evaporator receives the refrigerant in its liquid state. The condenser aids the heat transfer, the expansion valve regulates the flow of refrigerant into the evaporator, and the condenser pressurizes the refrigerant.

This process varies based on the type of AC unit being used. Central air conditioners have a controller or thermostat used for both cooling and heating and the compressor and condenser are located outside. That’s because it’s a split-system air conditioner.

Different air conditioners, different processes

There are additional types of air conditioners, which validate the question, “how does an air conditioner work?” While they all have some of the same basic parts, the answer is that it depends. Additional types of air conditioners include:

• Packaged air conditioner
  A packaged system has the compressor, condensing coil, blower fan, and evaporator coil all in one place. They are used when a split-system air conditioner doesn’t have enough room, or the unit must be installed on the roof. With this system, warm air is pulled outside, but through return air ducts into the evaporator coil. The air passes through the evaporator coil as cooler air and returns through supply air ducts. The condenser coil releases the heat outside. Split-system type units are mainly used in homes and commercial buildings.



• Ductless air conditioner
  While most air conditioning systems fall under the central air label, this one doesn’t. They don’t require extensive installation because they don’t have ductwork distributing cold air. There is an indoor and outdoor unit connected by copper tubing, but the unit only cools the air in one specific room (think wall or window air conditioners). These units can also be installed on the floor and have multiple units connected to a main outdoor one. Ductless air conditioners are used in standalone offices, garages, sunrooms, sheds, home additions, and more.

The choice of what type of system to use is based on individual needs. If an entire house or building needs to be cooled, a central air system may be the best choice, as it covers large spaces. If there is just one room that needs to be cooled on a periodic basis, the ductless solution may be best. This breakdown covers the questions, "how does an AC work," and "how does central air work?" to give you a better understanding of what goes on behind the equipment.