From The Blog

What is an HVAC System and How Does it Work? 

Those of you old enough may remember a time when central HVAC – which is made up of air conditioning and heating components – was not standard in homes and businesses in north Georgia, but you’re well into middle age if so.

Having HVAC in your home or business is not even a question anymore and with good reason: The advances in heating and air technology have made it both affordable and a comfortable and even a healthy part of living.

Yet to keep your HVAC functioning properly requires periodic maintenance, and you may find yourself wondering why – and how – that maintenance occurs. You may even find yourself asking questions about heating and air in general and how each component works.

It is a good idea to have at least a basic grasp of HVAC so you can be aware of what needs service when and why – as well as what to look for when you need to purchase a new heating and air system or repair an old one. That is because the more you know, the more likely you are to make informed and money-saving decisions when it comes to all aspects of this modern but very necessary convenience.

With that in mind, let’s take a look at HVAC basics as well as a more in-depth look at all aspects of heating and air conditioning so you can have an idea of what goes into these marvelous machines and know all about HVAC.

HVAC Meaning: What is HVAC?

Let’s start by breaking down the HVAC acronym itself. HVAC is short for Heating, Ventilation and Air Conditioning.

Those are the three components that make up home and commercial HVAC. Traditionally, these parts work in unison in a system that contains elements of all three. However, modern HVAC also offers these solutions in smaller or separate pieces to better meet the needs of any structure.

What is an HVAC System?

An HVAC system features several parts of heating, ventilation, and air conditioning, all working in unison to deliver perfect comfort to your home, business, or other structure.

There are many components to each section of an office or home HVAC system, and the larger machines usually comprise some combination of air conditioners, heat pumps, furnaces, air handlers, boilers, ductwork, ventilation lines, filters, and other air quality products.

These HVAC system units do not always make up a complete system. For instance, a residential HVAC system with a heat pump will have no need for a furnace. And some new technology such as mini-split systems do not even require ductwork to heat or cool a room.

In short, an HVAC system is any combination of HVAC components that can keep a structure comfortable.

How Does an HVAC System Work?

Your HVAC system produces air that helps keep you comfortable year-round. And we will look below at how heating and cooling components work in depth. But in a grander sense, HVAC works via a thermostat communicating with the other components and telling them how hard to work.

When your thermostat communicates to your air conditioner or furnace to run, those units manufacture air at the temperature (and, in many systems, humidity level) you desire and then transfer it into the ventilation system, which distributes it throughout your house, office, or other structure.

The results are comfort that you enjoy via a process that you hardly notice – despite an impressive amount of work taking place to produce it.


The job of the furnace is to produce warm air quickly and deliver that indoor heating around your home or commercial building. Furnaces are still the best method of quickly warming your house – though they may not be as energy efficient as other methods of heating.

Furnaces also come in many forms, but the three basic types are:

  • Electric
  • Gas
  • Oil

Each type of furnace has pros and cons, but each works on the same basic premise:

Cold air from your house enters the furnace via incoming ventilation. There the heat source (a flame produced by natural gas or oil, or heated wiring in the case of an electric furnace) warms the air within the unit’s heat exchanger. The warm air is then directed into your home or office by a blower fan through outgoing ventilation. (Any combustion exhaust is released from the furnace through an exhaust pipe.)

The process continues/repeats until your desired indoor temperature is reached. The furnace then goes dormant until it is required again.

A furnace is not to be confused with a boiler, which heats steam to help heat your home. Boilers are very popular in the northeast, where are they used to colder winters than we are here in north Georgia.

Air Conditioner

Living in north Georgia, you are probably acutely aware of how important it is to have functioning air conditioning. Spend a summer here without one, and you will quickly realize why (throughout the 1980s and 90s) they became standard in every home. Modern air conditioners are probably older than you may think – the technology was invented in 1902. But their evolution also means they are now incredibly efficient and produce amazing comfort at a fraction of the energy usage once required.

Air conditioners work by removing heat and humidity from the air inside your home, office, or commercial space. This cooled air is then circulated around your house, etc., via your ventilation system.

There are also, of course, different kinds of air conditioners, including window units and ductless mini-splits that deliver cold air straight into a room without the use of ventilation systems. Other air conditioners, including many modern units, feature multi-stage units that run at different speeds to help increase efficiency.

The process that air conditioners utilize also scrubs the inside air of moisture, which has the added healthy aspect of discouraging mold, mildew, and bacteria growth.

Heat Pump

The technology that heat pumps utilize is actually even older than air conditioners, having been invented in 1856. However, heat pumps did not become common for HVAC until the energy crisis of the 1970s sent people scrambling for more energy-efficient ways to heat and cool their homes.

Installed outside your home (like a whole home air conditioner’s compressor and condenser parts), the heat pump can produce both warmer and cooler air inside your home.

That’s because a heat pump pulls heat from the air. In warmer months it culls the heat from your indoor air and expels that heat from your home. Meanwhile, in colder months, a heat pump strips heat from the outdoor air and then transfers that warmer air indoors.

Heat pumps are all electric, using refrigerant to complete their process. However, some heat pump systems are also equipped with electric heat strips on the indoor fan coil to ensure warmer air – as the typical heat pump process pump doesn’t always deliver the warmest air. Yet it is an extremely energy-efficient way to heat and cool any type of structure.

What Are the Other Components of an HVAC System?

Each furnace, air conditioner, and heat pump also includes a whole range of HVAC system components that must work in concert with other parts of the HVAC system to produce ultimate indoor comfort.

But what are those parts? We’ve mentioned some of them already, but let’s look more in-depth.

Air Exchangers

Just like it sounds, air exchangers exchange stale indoor air for fresh outdoor air. Utilizing multiple fan and vent systems, the air exchanger pulls in fresh air from outside and then blows out stale indoor air.

Having an air exchanger installed in your home has become more and more common, and they work with your existing HVAC to improve indoor air quality and comfort. Air exchangers also help you prevent indoor allergens by ventilating them outside. They also improve indoor humidity control by better removing hot air inside your home (warm air collects more moisture).

Evaporator Coils and Coolant

Evaporator coils and coolant work in concert inside standard home air conditioner units to allow them to produce, crisp, cool air.

How they work:

Coolant is a chemical (also called refrigerant), and when used with a compressor, a condenser coil, and an evaporator coil, they quickly convert the refrigerant from gas to liquid and back again. The compressor raises the pressure and temperature of the coolant gas and sends it to the condenser coil where it is converted to a liquid. Then the coolant travels back indoors and enters the evaporator coil. Here the coolant evaporates, which cools the indoor coil. A fan blows your home’s warm air across the cold evaporator coil. The heat in that air is then absorbed into the refrigerant. The now cooled air is then circulated throughout the home while the heated evaporated gas is sent back outside to the compressor, where it is released into the outdoors and the coolant returns to a liquid state.

Also, because coolant (refrigerant) is the same as what is used in refrigerator technology, you will sometimes see HVAC referred to as HVACR — the “r” is for refrigerant.

Vents/Registers and Ductwork

These serve to move the air around the home or office. And it’s not just a question of bringing heated or cooled air into your home, ducts also take in the air sitting in your home and move it through your heating and cooling systems to ensure a constant flow. All the while, the air inside your ductwork must maintain a consistent pressure to function properly and ensure air moves throughout your home and does stagnate in hot or cold spots.

Having a fully functional ventilation system is just as key to comfort as an air conditioner or furnace. That’s because a duct system that has holes or tears cannot maintain proper pressure and thus will not be able to circulate air at the rate you need for total comfort. Worse, your thermostat will notice these differences and think that your air conditioner, furnace, or heat pump is not producing enough air and thus ask it to run harder than is necessary to produce the proper temperature. So, as you can see, air conditioning, heating and ventilation are all related in terms of your comfort.

A Thermostat

Think of the thermostat as the brain of your home’s comfort systems. You tell it what temperature you want, and it, in turn, tells the air conditioner and heater how hard to work to obtain and sustain those temperatures.

A traditional thermostat works off an internal thermometer so that it knows when the correct temperature is attained. However, modern “smart” thermostats are much more intuitive. They can gauge outdoor temperatures and dew points to help determine how those affect indoor temperatures. They also learn your home habits – such as when you leave, when you sleep, etc. – so that your HVAC runs as efficiently as possible (only using the absolute minimum amount of energy to keep you as comfortable as possible).

Modern thermostats can also be controlled by apps so that you have access to your home comfort no matter where you are.

Types of HVAC Systems

There are myriad HVAC systems you can use to deliver perfect comfort to your home or office. While you may be used to traditional, whole-home units, there are developments in HVAC technology and types of HVAC systems that can meet a wide range of needs – all at an efficiency level and budget that satisfies your requirements. Here’s a look at the various HVAC system types.

Split System

This type of HVAC system is ideal for larger homes with plenty of space. That’s because, in a split system, the condenser and compressor are housed in an outdoor cabinet. Meanwhile, another indoor cabinet will hold the evaporator coil. It also requires an air handler to function properly. The indoor and outdoor components are connected by a cooper tube, which moves cold air to the house or office.

Split systems can include multiple heat pumps or air conditioners – which is often the case with larger homes and buildings. They can also be paired with a gas furnace or a fan coil located inside the building.

Hybrid Heat Pump

A hybrid heat pump, sometimes called a dual fuel pump, has both an electric heat pump and a gas furnace. This allows the system to switch between the two types of heating, depending on the season, temperature, and function needed. The result is that a hybrid heat pump maximizes efficiency while also effectively heating and cooling your home.

Ductless Mini-Split

A ductless mini-split is a self-contained heating and cooling unit that can be attached to a wall in a room. This unit emits both air-conditioned and heated air into the room, has its own thermostat and does not require ductwork. These units are becoming increasingly popular, especially in cases where it is not easy to install ductwork or immediate cooling/heating access is required. Utilizing multiple mini-splits allows you to create multiple zones so you can create different atmospheres from room to room.

Ducted Mini-Split

These units look much like a ductless mini-split, as they are compact wall units. However, it does have concealed ductwork to circulate air throughout your home from an air handler located in an area like an attic or crawl space. Ducted mini-splits offer the same control as ductless units so that you can create multiple zones. They are more efficient than central air conditioners due to less ductwork – the more ductwork, the more energy is needed to push the air through it.

Packaged System

This type of HVAC combines multiple components – air conditioners, furnaces, or heat pumps, for instance – into a single unit. This is a perfect option for homes with little indoor space or little underground space in which to store the HVAC units. Packaged systems are typically very efficient, easy to install, and quiet to run. This is the traditional central air conditioning system that many people think of when they think of home air conditioning units and central heating

Who Can Service HVAC Equipment?

Do you need or think you need a new HVAC system? Perhaps your current heating and air systems require repair? Or maybe a simple HVAC maintenance or service call is all you need. Whatever your heating and air conditioning needs, know that Conditioned Air Systems is here and ready to help with your HVAC needs in north Georgia and metro Atlanta.

For almost 40 years, Conditioned Air Systems has been helping residents throughout north Georgia and metro Atlanta to experience fully functional and comfortable HVAC in their homes, businesses, and beyond.

Our commitment to customer service means that your satisfaction is our ultimate concern – that means we will be honest and open with you about the repair/replacement situation for your heating and air units. And, because we are a factory-authorized dealer of some of the leading names in the HVAC industry, our NATE-certified technicians can repair any system – or replace it with one guaranteed to give you years of comfort. Please contact us today to experience the Conditioned Air Systems difference: 770-536-7509.

Conditioned Air Systems

Ensure Your Home’s Temperature is Stable Year-Round

At Conditioned Air Systems, we’ve been helping homeowners throughout north Georgia stay comfortable – no matter the weather outside – at peak efficiency since we opened our doors in 1983. And we’re always happy to help you achieve that same satisfaction.
Trane units outside home