How Do Air Conditioners Work?

Many people have mistaken ideas on how do air conditioners work. For example, some think the system takes fresh air from outside and adds coldness to it before delivering it inside. That is far from the truth. An air conditioner does not take air from outside, nor does it have the ability to add coldness to the air.

Here is the actual mechanism of the air conditioner:

An air conditioner has a line containing refrigerant, a chemical responsible for heat transfer. The refrigerant flows in a closed loop, which connects the components in indoor and outdoor units. Also known as freon, refrigerant is liquid when idle. Once it carries heat, it turns into gas. The heat is transferred to the outdoor unit, and the refrigerant returns to a liquid state.

Components in an air conditioner work together to cool your home. For example, the outdoor unit contains a compressor, which pumps refrigerant through the system. The compressor is the heart of the air conditioner and circulates refrigerant between the indoor and outdoor units. The outdoor unit also contains a fan, which blows air over the coils and helps remove heat from your home.


Once the AC is on, the indoor unit will suck in the indoor air and send it to the evaporator. The coils will absorb the excess heat and humidity from it. The heat will go into the refrigerant, and the moisture will flow through the drain line. This evaporation process lowers the air temperature and humidity before the air makes its way back into the room.

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A compressor is a pump inside the outdoor unit. This component is responsible for pressurizing the refrigerant. With higher pressure and temperature, the refrigerant will flow from the evaporator to the condenser. The compressing process also forces the refrigerant to dissipate the excess heat through the condenser coils.


Also located in the outdoor unit, the condenser is in charge of the heat transfer process. After releasing the heat, the refrigerant turns back into liquid form. The next step is to send the refrigerant back to the evaporator to repeat the heat transfer.

Expansion Valve

Between the condenser and the evaporator is an expansion valve, which opens and closes periodically. It may seem like a simple job. But, this part is vital to maintain the balanced loop of the refrigerant. An expansion valve regulates how much refrigerant flows back from the condenser to the evaporator.

Other Components

Besides the vital components mentioned above, there are also supporting components that contribute to the cooling process. Here are some of them:

  • Thermostat: controlling the operation of the whole system based on the sensor, adjustment, and any features it has.
  • Blower: sending the conditioned air back into the room.
  • Condenser fins: moving the warm air away from the condenser.
  • Condenser fan: blowing air to cool down the refrigerant while also preventing the condenser from overheating.
  • Air filters: capturing pollutants, especially dust and debris, and preventing them from entering the machine or flowing back into the room.
  • Ductwork: In a central air conditioning system, the ductwork is in charge of distributing the conditioned air and sucking in the air to be conditioned.

There are various types of air conditioning systems. But, they all share the same basic mechanism. Air conditioning systems that contain only a single unit have all the components, just in the same unit. Therefore, such models are not as reliable for long-term use.



ECM Air Conditioning, with its headquarters located in Boynton Beach, FL, provides air conditioning services within Palm Beach County, Broward County, Martin County, and St. Lucie County. If you’re looking to have a new HVAC system installed, we’re on-call and ready to assist you. So if you’re in need of an HVAC installation, don’t hesitate to contact us today to schedule an inspection! Our HVAC installation experts will check your ductwork, measure, check wire sizes, and more before making recommendations to ensure maximum efficiency and comfort. Call us at 561-295-1763 or contact our HVAC installation team online by clicking here.


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