What Are the Major Parts of an Air Conditioner?

Your air conditioning system is composed of many parts. However, there are some major components that are large and expensive to replace or repair. Most people know about the box that sits behind their house, but they cannot tell you the difference between the evaporator and condenser coils. Knowing the basics will help you avoid and identify possible problems.

Air Conditioning Fundamentals

Before delving into the individual parts, it is important to know the fundamentals of how your system works. There are two primary functions your AC unit performs.

The first one you may think about is circulating air through your house and cooling it as it does so. The second is actually a function of the first, which is transferring heat from the air inside of your home to that outside of your house.

The refrigerant in your system is how this transfer happens. The refrigerant absorbs the heat inside and then releases it outside. To accomplish this transfer, your unit has to change the refrigerant’s pressure during the process.

When the refrigerant moves outside, it is pressurized to allow it to more easily release heat. When it moves into the inside part of the system, it drops the pressure dramatically, which makes it extremely cold.

If any of the parts fail to work properly, it either restricts the air from circulating properly or causes problems with the refrigerant’s pressure.

Condensing and Evaporator Coils

The refrigerant runs through two different sets of coils. Inside your house is the evaporator coil, which is normally located near your air handler or furnace. The refrigerant’s pressure is dropped by an expansion valve just before entering the evaporator coil. This makes this set of coils very cold, allowing it to absorb the heat from the air very quickly as it moves through the coils.

Outside of your home is the condensing coils. The refrigerant is compressed before entering these coils, intensifying the heat it absorbed inside the house. Air moves through the condensing coils, and being that the outside air is cooler, it absorbs the heat from the coils.

Both of these coils are prone to collecting dust, dirt, and other contaminants that will restrict airflow. To keep both of these working efficiently, they should be carefully cleaned during regular seasonal maintenance.

If they are damaged and start leaking refrigerants, they will need to be replaced. A trained technician will help you evaluate your options regarding whether or not replacing a single coil is in your best interest.

Condensing and Circulating Fans

The refrigerant will not do its job without air moving through the coils to transfer heat properly. There are two primary fans within your air conditioning system: one inside and one outside.

The fan inside is actually used for both your air conditioning and your heating, called the circulating or blower fan. This fan draws air into your system through the air intake vent and through the filter. It then forces the air through the evaporator coil, cooling it down and bringing it back out into your house where you can enjoy it.

The condensing fan, on the other hand, is outside in the condenser unit. It draws air from around the unit through the condensing coil, where the air absorbs the heat from the coils. It then vents that hot air through the hole in the top of the condensing unit.

To keep these working properly, they need to be checked regularly. If they are not a sealed unit, the bearings need to be lubricated to keep them from wearing prematurely. They also need to be cleaned, tightened, and balanced. All of this happens during a regular maintenance visit.


The compressor is also outside in the condensing unit. This important component increases the pressure of the refrigerant before it travels to the condensing coils. If this component fails, you will have to replace it. You will have the option to replace it on its own or as part of a larger replacement project. Your air conditioning technician will consider the age and condition of your unit as they guide you on your options.

When you suspect a problem with your air conditioner, seek professional service quickly to avoid unwarranted damage to your unit. Jco Heating A/C Electrical has been trusted around Springfield since 2002 for reliable and trustworthy air conditioning repair, maintenance, and replacement. We also offer heating installation, repair, and maintenance, along with air quality improvement solutions. Give us a call to schedule your air conditioning maintenance or repair today.