Central air conditioning offers the most effective home temperature control solution available. When you have central air, you should learn how it works to help you use it properly and take the proper actions to keep it running efficiently for as long as possible.

In this article, we will cover:

  • The different components that make up a central air conditioner
  • How central air conditioning actually works
  • Some best practices that will help you get the most out of your central air conditioner

Components of a Central Air Conditioner

Before you learn how central air works, you should understand the different components. A brief overview will help you properly comprehend technical explanations and hold an intelligent conversation on the topic when necessary.

The main components of an air conditioner unit are:

  • Compressor
  • Condenser
  • Evaporator
  • Blower
  • Ductwork
  • Thermostat

Condenser Unit

The condenser unit refers to the large device outside your home (most likely on a concrete foundation). The condenser cools down the gas and transports it back inside once it’s cool. Since it’s located outside, you want to take special care to keep leaves and other debris out of the unit.

The condenser unit contains the following parts:

  • Condenser fan
  • Condenser coils
  • Compressor
  • Capaciter
  • Contactor


The compressor, found in the condenser unit, acts as the heart of the entire process. It changes low-pressure gas to high-pressure gas using “working fluid.”

Evaporator Unit

The evaporator unit is what we call the main unit inside your home, likely found by your home’s furnace. When the air reaches the evaporator unit through a pipe, the refrigerant cools off the air to a comfortable temperature.


The blower facilitates the delivery of the cooled air by taking in the hot air in the area and replacing it with cool air.


Ductwork refers to the vents that transport the conditioned air throughout the entirety of your home. Some people refer to them as the “lungs” of your home. If the air can’t get through to a certain area, that room will not have proper cold air.


The thermostat communicates with your central air conditioning system to regulate the temperature of the air coming into your home.

How Central Air Conditioning Works

Once you have an understanding of the different components of central air, you will have a better understanding of how it works. See the following step-by-step explanation of central air functions.

Step One: Provide Power to AC

Start by providing power to your HVAC system. This involves providing electrical power to the condenser unit, evaporator unit, and thermostat. You may have the components on different circuits, so ensure you provide power to everything. You will notice power when you hear noise or see lights on the different units.

Step Two: Set Thermostat Temperature

Set the temperature on your thermostat to your preference. Most modern thermostats have easy-to-read and control digital displays to make this step easy. Read the user manual for your specific thermostat if you run into problems since controls vary greatly.

Step Three: Hot Air Enters Evaporator

When your air conditioner starts up, it will suck in the warm air in the room into the evaporator, where the evaporator coils will soak up the heat and converts it from a liquid to a gas.

Step Four: Air Travels to Compressor

At this point, the warm air travels outside through the pipes to the condenser.

Step Five: Compressor Adjusts Refrigerant Levels

The compressor compresses the gas in the air that comes through it by literally squeezing it between two solid materials. This process allows the system to analyze how much refrigerant is required to produce the desired results.

Step Six: Release Heat Outside

The hot air originally absorbed by the evaporator coils at the beginning of the process now expels into the fresh air via the condenser unit. The hot air will dissipate into the fresh air until you can no longer distinguish it.

Step Seven: Cool Air Replaces Warm Air

With the heat removed, the system replaces that space with refrigerant. This refrigerated air travels back inside to provide cool air.

Step Eight: Cool Air Travels Through House

Once inside, the cool air will travel through the ducts to reach all of the nooks and crannies of your home. Further areas of your house will take longer to cool down, but you should notice a difference shortly after the process starts.

Step Nine: Cycle Repeats Until You Reach Desired Temperature

This cycle of expelling hot air and replacing it with refrigerated air continues until your system recognizes that you finally reached your desired temperature.

Step Ten: Enjoy!

The last and most enjoyable step of the process involves you relaxing comfortably in your temperature-controlled home.

Best Air Conditioning Practices

You want your central AC to keep you comfortable while also keeping your utility bills at a reasonable cost. The more efficiently your unit runs, the less you will pay in utilities and the longer the HVAC system will last.

Every air conditioner comes with a SEER rating that indicates its efficiency levels. Check your user manual to learn your unit’s efficiency rating. Of course, you can take steps to improve efficiency to the best of your ability. Try these best central air practices to make the most of it.

Buy a Smart Thermostat

A smart thermostat will change the temperature for you automatically based on how you program it. If you don’t program it, it will learn your patterns to adjust to the best of its abilities.

A smart thermostat also gives you the power to control the unit from an app on your phone. You will also get important notifications and usage reports which you can use to tackle a problem as soon as you notice it.

Get Regular Maintenance

Regular maintenance will keep your HVAC system in tip top shape. Call Oak Island Heating and Air Conditioning to have a local HVAC technician perform professional HVAC maintenance in san Marcos. Regular maintenance includes:

  • Cleaning the filter
  • Cleaning condenser unit
  • Cleaning evaporator coils
  • Cleaning the ducts
  • Inspection

Set Proper Temperature

The temperature setting on your thermostat can play a large role in how well your central AC works. Most experts suggest keeping the temperature at 78 degrees in the summer when at home. You don’t need to heat the home while no one will enjoy it, so consider raising the temperature to as high as 85 degrees. At night, try a temperature of 80 degrees. You may even consider opening the windows and giving your unit a break on, especially nice nights.

Call For Central Air Conditioning Service

Oak Island Heating and Air Conditioning provides professional HVAC services in San Marino you can rely on. They use the best products on the market and work under a business practice that puts the customer first. Oak Island Heating and Air Conditioning offers heating and cooling installation, repair, maintenance, and indoor air quality solutions.

ContactOak Island Heating and Air Conditioning to schedule an appointment today!

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