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You’ve probably heard of the term HVAC at some point in your life. There is nothing wrong with not being aware of its definition and how it works. After all, it only affects you once you own a property and need to install a system for your home. Consider this article your crash course in the basics of HVAC. We’ll explore what “HVAC” stands for, look at different types of HVAC systems, and run down the key details you should know about heating or cooling an interior space.


What is HVAC?

HVAC stands for Heating, Ventilation, and Air Conditioning. Essentially, an HVAC system is just the umbrella under which a building’s central heating system, central cooling system, ductwork, vents, and other associated components fall. Primarily, the goal of an HVAC setup is to provide the perfect indoor environment regardless of what the outdoor conditions are. Heating and air conditioning are self-explanatory elements of this equation. Ventilation, meanwhile, refers to the process of exchanging air to provide high-quality air indoors.

As occupants in a home breathe out carbon dioxide, there is no way of the gas escaping other than via the windows. However, since the outdoor conditions are often either extremely hot or cold, you don’t want to expose your interior to those elements consistently. Ventilation allows for the fresh, oxygenated air to flow through the indoors. Additionally, it removes bad odors, moisture, and other contaminants in the air to create a healthy environment for occupants. Thus, HVAC plays a vital role in preserving indoor air quality for a home.

One thing that is useful to understand is that you do not necessarily need to install combined heating, air conditioning, and ventilation system in your home. While these systems often come as a packaged deal—and while most people do opt for a combined system—each element of the HVAC system can also work independently.


The Need for HVAC

Every year around three million HVAC systems are replaced in the United States, with about $14 billion spent on repairs or services. These systems account for almost half of the average household’s energy consumption. As a result, selecting a high-performing system is critical to regulating energy usage and ensuring that household bills remain as low as possible.


The Components

Even though they’re referred to under the broad, umbrella term of “HVAC,” there are individual components in each system that do the work of keeping your home warm in winter and cool in summer. Heating requires a heat pump or a furnace. There is a possibility of using both via a duel fuel system. Cooling requires an air conditioning system.



The furnace takes the most space in the HVAC  or split system —and perhaps more importantly, consumes the most energy. It contains ignitors or burners that are responsible for heating air. Air is transported through the heat exchanger and then propelled through a network of ducts to the rooms throughout the home.


Heat Pumps

On the other hand, heat pumps extract air from the outside and transfer it to refrigeration coolant. The coolant absorbs the heat from the outside air and then uses it to heat your home. Even if it is very cold outside—say, 20 degrees—the air heat pump can still extract and absorb the heat from the exterior air and use it to provide indoor heat.


Air Conditioning

Primarily, the air conditioner is responsible for cooling and monitoring the air through the thermostat. Most air conditioners have split systems where one part is situated outside the property, and the other is inside. There are various types of air conditioning systems available to suit the unique needs of a property. Some AC units, for instance, are window AC—compact devices that sit in an open window and play the role of cooling, ventilating, and dehumidifying a small space. While window units work for small apartments or single rooms, though, they aren’t sufficient for whole-house cooling in most cases. A central air home or business air conditioner, which uses ducts to distribute cool air to vents throughout a building, is the more effective option for larger buildings.


As we’ve demonstrated, HVAC systems are more than just agents for warm air cooling or cold air heating. They also provide clean, quality air for occupants of a building. This process can occur because of the oft-overlooked ventilation aspects of your HVAC system.

Two types of ventilation can occur in a home or commercial building. The first option is natural ventilation: opening your doors and windows to allow fresh air in and provide an opportunity for the bad, carbon dioxide-filled air to flow out. The second option is mechanical ventilation through an HVAC system. While most buildings tend to see some of both types of ventilation, outdoor temperatures, weather conditions, air pollution, or other factors make it difficult for any home or business to be adequately ventilated just through the use of open doors and windows. For one thing, modern buildings are more air-tight—a design feature that helps with energy efficiency, but which also makes it more difficult for air to pass through naturally. Hence the need for a mechanical system.

During HVAC-aided ventilation, the air is drawn into an air handler unit after going through filters that remove dust, dirt, allergens, and other contaminants. After this process, the clean air is sent to be heated or cooled and finally distributed either through a network of ducts or directly into rooms throughout the building. The same ducts that are vital to air distribution in a central heating or cooling system play the role or removing and filtering contaminated air.


The Air Conditioning System Explained

The ultimate goal of air conditioning is to cool the inside, creating an environment with ideal temperatures. The system uses its major components—including an evaporator, a condenser, a compressor, and an expansion valve—to operate much like a refrigerator would.

To put the process into even simple terms, picture a large open water tank. Over time, the tank receives water via various sources. However, your goal is to maintain a particular level of water in the tank. To operate efficiently, the tank will need an outlet at the bottom end to release excess water as new water is added. Apply the same principle to air conditioning, where the water tank represents a room, and the water in the tank is heat. There are multiple sources of heat inside a room, but you require the temperature to be regulated at a consistent level. The outlet at the bottom of the tank represents your air conditioner, which assists in cooling the room through the removal of heat.



To maintain the efficiency of your HVAC system, it’s recommended that you regularly service the system to ensure it is fully operational. Duct cleaning is essential and should be done regularly to preserve a healthy indoor environment and an energy-efficient HVAC system. Working with the right HVAC contractor can help you navigate every step of the process, from HVAC system selection and installation to ongoing care and maintenance.