Anatomy of a Central Air Conditioning System

If you’ve ever received a quote for air conditioning or furnace repairs, or tried to do some DIY maintenance on your HVAC system, you may have found yourself a little confused with the terminology regarding the average central heating and cooling system and how it all works.

From the thermostat to the burner, condenser coil to the compressor, there’s a lot of components that work together to pull the hot or cold air from your home, cool or warm it, then cycle it back through your home. Here’s a rundown of the anatomy of central HVAC systems and how it all works together.



Traditional furnaces are somewhat simpler to understand than heat pumps or air conditioners. They don’t pull hot or cold air out of the air, rather they simply heat air and circulate it through your home’s ductwork.

• Burner – Essentially the burner is the component through which the fuel source is delivered and burned to create heat.

• Heat Exchanger – The heat generated from the burner is transferred to the air in the heat exchanger before being distributed.

• Ductwork – The air heated in the heat exchanger is sent through your home’s ductwork for dispersal.

• Vent – Ventilation in the form of a flue or vent pipe is necessary for traditional furnaces burning some form of fossil fuel, whether heating oil, natural gas or propane, to exhaust the byproducts of burning the fuel.

Air Conditioners

Most central air conditioning systems are split into an indoor and outdoor unit. The outdoor portion of your central air conditioning system is the large box that sits either on the side, behind or even on top of your home. There are several key components to the outdoor unit.

• Condenser – This is also referred to as the condenser coil. It circulates refrigerant from the evaporator coil and helps push hot air out of the system.

• Compressor – Near the condenser you’ll find the compressor, which many consider to be the “heart” of any HVAC unit. This component pumps refrigerant from the evaporator coil to the condenser coil.

• Outdoor Fan – This is located on the side or top of your outdoor unit. It moves air through the condenser coil to help dissipate heat from the condenser and push hot air out of the system.

The internal portion of a central air condition system is called the air handler. You’ll often find it in an out-of-the-way place, like a closet, attic or basement, sometimes right on the other side of a wall from the outdoor unit. The components inside the furnace are just as crucial as those outside.

• Blower (Fan) – This component pulls the hot air from your home and blows it over the evaporator coil to be cooled or over the heat exchanger to be heated, and is eventually recycled through the house.

• Evaporator Coil – As mentioned above, the evaporator coil takes in refrigerant from the compressor which absorbs hot and humid air coming from the blower.

• Refrigerant Lines – These thin copper pipes carry refrigerant through the system, most notably from the evaporator coil to the condenser coil. They allow the movement of refrigerant between the indoor and outdoor equipment.

• Filter – When air comes in from the blower, it first travels through your filter, which keeps indoor air quality nuisances like dust and pollen from being recirculated through your home.

• Thermostat – You’re likely very familiar with your thermostat and how it functions. Setting the temperature on your thermostat tells your system to begin pushing air into the furnace and start the cooling/heating process.

Other Components of Note

Apart from the most critical components, there are some other parts to your central air conditioning and heating system worth mentioning as they may also need service at some point.

• Plenum – This is a large box that attaches to the evaporator coil and helps distribute air to ductwork.

• Condensate Drain and Pan – These two components work together to rid the plenum of excess moisture. As moisture collects in the tray underneath the evaporator coil, it’s removed through the drain, which runs from the plenum to the outside of the home. In humid environments, such as San Antonio can get at certain times of the year, it’s not entirely uncommon for these pans to overflow or for drains to become clogged, resulting in spillage.

• Ductwork – The ductwork running through your home is responsible for distributing air, and includes the vents. They connect each room of your house to your air conditioning and furnace.

Central Air Conditioning and Heating System Services

A central air conditioning or heating system is quite complex. Much like any other machine or piece of technology, proper function is dependent on all the parts working seamlessly with one another to accomplish one goal. This is why if you’re looking for air conditioning maintenance, heating service or HVAC installation, it’s crucial you work with an HVAC professional you can trust. The expert technicians at Aramendia Plumbing have been assisting San Antonio residents for more than two decades. Call 210-654-1034 or visit online today for a quote.

5511 Brewster St.
San Antonio, TX 78233

About Us

Aramendia has been serving San Antonio
and the surrounding areas for over 29 years and we pride ourselves on the trust and reputation we have earned over that time. Our loyal customers know us as a reliable and trustworthy service company that will quickly send a highly-qualified technician to their home or office to take care of them.  In August of 2017, Aramendia became part of the Service Experts family. As a Service Experts company, Aramendia will continue to serve San Antonio and the surrounding area.