How an Air Conditioner Works

June 14, 2016

August is here with its 90-degree temperatures. And the best way to beat that heat is by cooling off with some sort of air conditioner.

But have you ever wondered exactly how that air conditioner makes cool air? Let’s take a look.

The Basics

Your air conditioner operates the same way as a refrigerator, but obviously cooling a much larger area (at least we hope your home or office is larger than a fridge).

Both use a refrigerant that converts easily from liquid to gas and back to liquid again. In your A/C, the refrigerant is on a regular loop from the outdoors to the inside of your home.

It goes into the home as a sub-cooled liquid that evaporates and assembles or takes in heat from your indoor air, expands back into vapor, then back to the outside condensing unit where it dissipates the heat and is switched back to a sub-cooled liquid.

The Components

Your AC system is made of four main pieces: an evaporator coil, a compressor, a condensing coil, and an expansion valve or metering device.

The piece where your refrigerant evaporates from a sub-cooled liquid to a super-heated vapor is called the evaporator coil, which may be in your attic or in your garage. As warm indoor air is blown across the cold evaporator coil, heat is removed from the air, and the cooled air is blown among your home.

From the evaporator coil, the now super-heated vapor refrigerant goes back to the compressor located in your outdoor condensing unit. The compressor increases the pressure of the vapor until it turns into a hot, high pressure vapor.

The now super-hot vapor enters the condenser coil where less hot air blows across the coil, eliminating the heat to the outdoors, and changes the refrigerant to a sub-cooled liquid. The sub-cooled liquid refrigerant is returned to the indoor evaporator coil where, through an expansion valve or metering device, the process is replicated.

Your air conditioner is a constant loop of physics at work. We know the important thing to you isn’t really how it works, but that it’s working the right way.


Still don’t feel like you fully understand how an air conditioner works? No worries. We understand fully. Give us a call at 515-278-2900 or contact us online for all of your air conditioner needs.