How Does an Air Conditioner Work?

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Updated September 9, 2022

If you are new to the world of indoor cooling, you may wonder how does an air conditioner work. Even the best air conditioners, after all, can seem like magic until you understand the various components and how they interact. So how do AC units work? Keep reading to find out.


  • Air conditioners come in many shapes, sizes, and designs, but the air conditioning process operates using similar principles.
  • Outside air is sucked into the AC unit via a fan, where it is cooled by condenser coils, cold refrigerant, and a compressor.
  • The air is then pushed throughout the home via ductwork, an expansion valve, another fan, copper tubing, and various air vents.

What is an Air Conditioner?

AC units are appliances that provide cool air during those hot summer months. Some designs are simple and some are complex, like ducted systems, ductless units and portable air conditioners. If you’re wondering, we have a specific guide on how portable air coolers work during the cooling process. If you are wondering how to fix an air conditioner, learning all about the various components will help.

Insider Tip

Most AC units require access to the outdoors via copper tubing, a large duct, a vent, or a window.

Air Conditioner Parts

How does a gas air conditioner work, or how does any AC work? It all depends on the components and how they interact. Learning about these parts will help when you wonder why your air conditioner is not cooling the house, in addition to other queries, especially when you’re running into trouble during a hot summer day and your home is scorching with unwanted heat.

Outdoor Unit

If you have central AC, or if you are wondering why you are having dual-zone air conditioning problems, the heart of your appliance rests outdoors. This exterior unit includes a fan that blows air into the house via ductwork or tubes, a condenser coil to cool the air, and a compressor to assist with cooling. Other types of AC units, such as window units, are similarly designed, but the various components are not housed in an outdoor unit. For instance, with a window unit, these parts are built right into the system.

Indoor Unit

A home’s indoor unit is paramount when learning how a central AC unit works. This unit includes an evaporator coil to reduce errant moisture and another fan to further push the cooled air throughout the home. Sometimes this indoor unit also includes a furnace or a heating element of some kind, in the case of hybrid HVAC systems that cool and heat to maintain a comfortable temperature in your indoor space year-round.

Ductwork and Vents

These components are reserved for central units or similarly designed AC appliances. Once the outdoor air is cooled by the compressor and condenser coils, the fan pushes the air through copper tubing into the home. Once inside the home, the newly cooled air travels through the indoor unit and into assembled ductwork. The cooled air travels through these ducts until it is released through vents located throughout the house. The end result is fresh and cool air to help you live through extreme temperatures.


What is central air?

When it comes to types of air conditioners, central air units cool the whole home at once, thanks to a cool liquid refrigerant. This kind of modern air conditioning system helps reduce ambient temperature and heat energy. Though a central air conditioning unit that uses cold liquid isn’t cheap, central air conditioning systems can be a great investment if you have a large home and need to efficiently cool it.

How does ductless air conditioning work?

A ductless air conditioner still uses the same cold evaporator coils that a central air conditioner uses, but this kind of air conditioning unit only cools one room at a time.

Does an air conditioner take in air from the outside?

In nearly every case, be they outdoor units or window units, they take in air from the outside, where it is run through a condenser coil and refrigerant, and ends up as cold air.

STAT: A standard air conditioner or cooling system uses a specialized chemical called refrigerant and has three main mechanical components: a compressor, a condenser coil, and an evaporator coil. (source)

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