A Closer Look At The Important Components Of Central ACs

An efficient heating, ventilation and air conditioning system is essential to the comfort of you and your loved ones throughout the year. If you want to make the most out of your unit, then it’s important to know and understand the important components of a central air conditioning unit, which we shall delve more in this post.


This component is often the most visible part of your entire HVAC system. It’s installed in a prominent location, usually, an easily accessible wall and its role is to keep the home temperature at the desired level. When the ambient temperature becomes too hot or too cold, it triggers the heat exchanger or the evaporator coil to start circulating cool or warm air as required. The thermostat comes with an array of features including buttons to turn the temperature up or down, a fan switch and more.



This is one of the most important parts of a central air conditioning unit. It is ideally the biggest, requiring substantial space, generally in the basement, cellar, attic or a special closet that’s designed for that purpose. It’s role is to heat a supply of air that is to be dispersed throughout your home. The heating process is accomplished through one of four heat sources, namely; electric resistance, combustion, solar energy or heat pump.

The Heat Exchanger

This is a component that is located inside the housing of the furnace unit. The heat exchanger turns on when  the furnace is triggered by the furnace to generate warm air during the cold days. The component draws in cool air, warms it and the disperses it through the ducts and through the vents in to the various rooms.

The Evaporator Coil

The role of the evaporator coil is the exact opposite of the heat exchanger. It cools the air when the thermostat is set to lower temperatures during the hot days. It is located on the exterior of the furnace inside a metal enclosure and functions in a similar manner to a car radiator to emit cool air, which is then circulated through the ducts.

The Condensing Unit

This part is connected to the evaporator oil and it’s installed outside of the house. It contains a refrigerant which when cooled to a liquid via heat exchange the unit pumps it to the evaporator coil to be changed back into a gas.


This is simply a system of ducts that transport warm or cool air from the HVAC unit to the various rooms in your house. Ducts are usually made of aluminum, but they can ideally be manufactured from fiberglass, steel, polyurethane or flexible plastic.

Refrigerant Lines

These are responsible for carrying the refrigerant to the condensing unit in the gas form and return it to the evaporator coil in the form of liquid. Refrigerator lines are actually small tubes that are made of a sturdy heat and cold resistant metal like aluminum or copper.


These are rectangular outlets that transfer cool or warm air from the duct system into the various rooms of your house. They are located on or near the ceiling and are made of high and low-temperature safe metals. They are also fronted with angled slats, which we usually refer to as vents. Usually, they can be manually controlled in order to regulate the amount to hot or cold air that’s being directed into a room.

Air Filters

These are elements that trap dust and other airborne particles as air circulates the AC system. Filters contribute to both health and ideal AC operation and that’s why they are important components of the central air conditioning unit.

Benefits of Central AC Units

Cleaner Air- Since the AC system draws out air from the interior through air ducts, the air is transported through an air filter which gets rid of airborne particles like dust. Some complex air filters ideally remove microscopic pollutants which makes the air cleaner.

Indoor Comfort- central ACs help keep the home cool and minimize humidity levels

Quieter Operation- Since the compressor is located outside the house, the noise level inside from its operation is much lower compared to that of a free-standing AC.

AC Repairs

Naturally, central AC units call for repairs due to normal wear and tear as time goes by. Other than age, repairs often stem from overlooked maintenance and can be divided into various categories including drainage issues, electrical or control component failure, refrigerant leaks or major component failure.

Here is a list that shows some symptoms that lead to AC service calls:

-Your indoor thermometer is reading higher than the thermostat, but no air is blowing out of the vents.

-One part of the house is cool, but not the other.

-Air is coming out the vents, but it won’t cool down the thermostat setting

-Water leaks from the drain line

-The unit won’t run and ice can be seen on the coils

If your HVAC system shows any of these symptoms, you should turn off the AC setting at the thermostat and immediately contact a HVAC technician for advice. Turning off the unit could be particularly important if the parts are making unusual noises, frozen or emitting odd smells.

When the AC technician comes to your home, they will usually charge in one or all the following areas: supplies/parts, hourly labor, mileage costs, minimum trip charge and taxes. The technician should ideally be able to quote conventional items like price per pound of refrigerant or a minimum trip charge. However, don’t expect them to diagnose the issue or give an estimate of the total cost over the phone. Reputable and honest AC contractors will usually give on-site quotes for no charge, but repair trips more often than not, involve a minimum cost.

It always pays to plan ahead. Interview a few AC technicians when you are choosing one to your repairs on maintenance. Also, keep in mind that it is much easier to have scheduled yearly maintenance that to call for repairs at random times, especially when you need the AC working.