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At a time when it seems like we have new jargon and acronyms flying at us all the time, it’s easy to get bogged down in “information overload.” One term you may have heard in the past is “HVAC” — perhaps you heard it used by a landlord or a technician to describe your air conditioner, but is that all this term means? In reality, it’s a bit more complex than just the way you get cold air. Good HVAC is a fundamental element of modern building design and an essential contributor to how you stay comfortable at home. So what is HVAC? Let’s break it down piece by piece to make it easy to understand.


Breaking Down the Main Elements of HVAC Systems


HVAC is an acronym that breaks down into three component parts: heating, ventilation, and air conditioning. Right away, we can see that HVAC isn’t a complex concept: it’s a simple catch-all term for the systems we use to control the climate of interior spaces, whether that means temperature, humidity, or even air quality. No matter whether it’s the dead of summer and swelteringly hot outside or if snow flurries fill the air, HVAC systems work hard to keep us comfortable.


With a basic answer to the question of  “what is HVAC?” established, let’s look at each component of the acronym in greater depth, then explore the constituent parts that make it all happen. 




Most homes, except those in specific climate zones, will need some way to heat interior spaces during the autumn and winter months. Even some areas that typically didn’t have high levels of heating demand in the past may need these solutions as extreme winter weather patterns evolve. Today, we’ve largely moved on from fireplaces and wood-burning stoves. Modern heating options typically use the same “forced air” system of blowers and ducts that air conditioners use. Heating can include:


  • Natural gas or propane furnaces and condensing furnaces
  • Electric resistance heating
  • Heating oil-fired furnaces
  • Radiant heating systems, such as boilers and radiators




Without keeping your windows and doors open all the time, there used to be no easy way to remove “stale” air from interior spaces and to replace it with fresh air. The “V” in “HVAC” stands for ventilation, and its goal is to solve this problem — to make it easier to exhaust air to the outdoors while also bringing in a fresh supply as needed. Ventilation systems can range from the very basic, as in most homes today, to the highly complex, such as those needed to provide adequate ventilation in large office buildings and high-rises. 


Air Conditioning


The “AC” of HVAC is familiar to nearly everyone. Air conditioners use special chemicals and physical processes to create a cooling effect on metal coils over which air blows. Air conditioning is essential not only for controlling the interior temperature of a space, but for also controlling its humidity. The air conditioning process naturally pulls moisture out of the air, making your home more comfortable.


How Do the Parts of an HVAC System Work?


With a clear sense of what each part of HVAC stands for, let’s take a quick look at how the individual components work in a broad sense. Check out more in-depth information to learn about the specific hardware elements of HVAC systems, such as ducts, blowers, and returns.


Furnaces function by burning fuel and exhausting the hot gases of combustion into a “heat exchanger,” a large series of twisting tubes. The hot gas transfers or “exchanges” its heat to the tubes. Air blowing over these tubes warms and flows into the home until the air temperature matches the thermostat temperature.


Air conditioners work on the principle of the refrigeration cycle. A chemical refrigerant undergoes compression and expansion, absorbing and releasing latent heat in the process. This process takes place partially outdoors and partially indoors. The key element is when the liquid refrigerant turns to gas in evaporator coils. Like in a furnace, air blows over these coils, cools, and then goes on to cool the home.


Ventilation can take the form of active exhaust fans or passive vents that allow air to escape to the ambient environment outdoors.


What is HVAC? Our Connection To Comfort

Next time you reach for the thermostat to adjust the temperature and you hear the rush of air through your vents, think about the magic of HVAC and how it allows us to always enjoy comfort at home or work. When you don’t need to wonder “what is HVAC?” you can also more capably identify potential issues based on changes in operation. Knowing when to call a professional technician for servicing and assistance ensures you can more easily avoid major headaches and equipment failures in the future. Be sure you always know who to call for help, and always make an effort to connect with licensed, insured, and highly experienced service providers so this critical system gets the care it needs.