Serving Greenwood, Fishers, Carmel & Surrounding Areas

April 6, 2021

What Are the Major Parts of an Air Conditioner?

On a hot day in Greenwood, there is perhaps no more valuable piece of equipment than your home’s air conditioner. While AC units are easy to use, their inner workings are quite complex. As a homeowner, it is a good idea to understand how the air conditioner’s different components work. This knowledge will help you better care of your system and better understand when you need to call in the pros at Complete Comfort.

How Does an Air Conditioner Work?

At its most basic, an air conditioner’s job is to move heat from one place to another. In other words, an AC unit is responsible for taking heat that’s inside your house and moving it outside. In the process of removing heat from your home, your air conditioner also dehumidifies the air in your residence. This helps to make it feel cooler on your skin. This process makes for an efficient and effective way to keep your home comfortable on even the warmest days.


When thinking through air conditioner components, it is important to mention the thermostat. Thermostats utilize a temperature-sensing device, such as a metallic coil or mercury vial, to detect the temperature in your house. When the temperature reaches a certain level, the sensing device will reach a point where an electric circuit opens so that power can flow to your air conditioner. Your temperature selection determines the point at which this circuit opens. Mechanical, programmable, and smart thermostats are the three most common types of devices in use today.

Blower Fan

Without a blower fan, an AC unit from Complete Comfort cannot distribute the cold air that it produces. This fan pulls in warm air from your home and pushes it over the evaporator coil. Depending on your system’s size, there may be multiple supply vents so that your appliance can pull air from multiple locations in your house. This allows your home to cool more evenly. A blower fan pulls double duty because it also blows air over the heat exchanger when you are using your furnace.


The refrigerant in your air conditioner is what does the heavy lifting in terms of removing heat from your home. The formulation of the refrigerant compound allows it to be easily manipulated through pressure changes. These pressure changes alter the temperature of the refrigerant so that it can either expel or absorb heat as needed. At various points during the cooling process, the refrigerant can exist either as a liquid or a gas. Newer refrigerant formulations tend to be more efficient at cooling your residence and less harmful to the environment when they escape through small leaks in your refrigerant line.

Refrigerant Line

To move the refrigerant through the various components in your air conditioner, your system requires a refrigerant line. This line, usually made of copper, forms a circuit that connects most of the other components in your AC unit. In some cases, the refrigerant line in an air conditioner can develop small holes that allow the refrigerant to leak into the air. That is why it is important to have your refrigerant line inspected by Complete Comfort at least once a year so that you can maintain efficient cooling. At specific points, the refrigerant line forms two coils that are important to the cooling process. These coils are detailed below.

Evaporator Coil

The evaporator coil is located inside your home. While in the evaporator coil, the refrigerant is a very cold liquid. As the moving air from the blower fan passes over the evaporator coil, the temperature of the refrigerant inside the coil begins to increase. By the time it exits the evaporator coil, the refrigerant is often warm enough to be in a gaseous state. The evaporator coil is also where condensation from the humid air collects. This is why the evaporator coil sits over a condensate drain pan so that the condensate can drain out of your house.
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Condenser Coil

Located outside, the condenser coil is responsible for removing heat from the refrigerant. As the refrigerant flows through the condenser coil, a fan blows over the line to help expel heat into the outside air. As its temperature drops, the pressure in the refrigerant also decreases. To further aid in the expulsion of heat, the outside of your air conditioner’s outdoor unit is covered in fins that act as small radiators to help keep the system cool. Complete Comfort will inspect these fins to ensure they are not bent or dirty. This will ensure that your unit can properly expel heat.


In order for the refrigerant to expel heat, its temperature must be higher than the ambient air. To achieve these conditions, a compressor is used. A compressor increases the pressure of the refrigerant in the refrigerant line, thus raising its temperature. In general, the component that uses the most energy in a cooling system is the compressor. Fortunately, new air conditioners from Complete Comfort feature variable-speed compressors. These can produce less compression when the ambient air temperature is lower. Since the compressor motor has more than one speed, you can expect to save energy during the cooling process.

Expansion Valve

After the refrigerant leaves the condenser coil, it needs to be cooled further so that it is cold enough to remove heat from your residence. This is the job of the expansion valve. An expansion valve monitors the refrigerant’s pressure in the refrigerant line and constricts the flow of the refrigerant accordingly. On the other side of the expansion valve, the refrigerant flows at very low pressure, allowing it to cool to the point that it is cooler than the temperature inside your home.

Proper Maintenance

While these are the main components of an air conditioner, there are countless smaller parts involved in keeping your home cool as well. With dozens of components and hundreds of individual parts, it is easy to see why regular maintenance from Complete Comfort is so crucial. If you do not maintain your system regularly, smaller components can begin to malfunction and have a snowball effect that renders your AC unit unable to keep your home cool. The good news is that catching problems when they are only affecting small components tends to make repairs much faster and less expensive than they would be otherwise.

Your Hometown HVAC Experts

At Complete Comfort, we believe in empowering our customers with knowledge. That is why, when we are performing repairs, maintenance, or installation on your furnace or air conditioner, we will go to great lengths to explain to you exactly what we are doing. This transparency extends to our other services, too, including water heater installation, plumbing repair, pipe replacement and installation, sump pump repair and installation, indoor air quality remediation, and more. With over 15 years of excellent service to this community and countless five-star reviews to our name, you can count on us whenever you are facing a home comfort emergency. To learn more about air conditioners, be sure to contact us at Complete Comfort today.

When it comes to your home or business cooling system, if you find yourself in need of AC repair in Greenwood, IN, you need to know you have a trusted professional on hand to get you back to comfort levels in no time. That’s where we come in. We’ve been serving Central Indiana since 2003, and offer the highest quality of air conditioner repair and services in the area. Our technicians will treat you like family, and work with you to find the best possible solutions for your repair and comfort needs.