HVAC 101: Everything You Need to Know [pdf]

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Last Updated on March 16, 2023 by Noaman Adenwala

What is HVAC System?

HVAC primarily stands for Heating, Ventilation, and Air Conditioning. This system supplies heating and cooling to residential and commercial buildings. HVAC systems are found everywhere from single-family homes to submarines. They are usually done in new construction. This system use fresh air from the outside to ensure high indoor air quality.


HVAC systems include several types of equipment, including Stoves, Boiler, or Heat Pump – To produce heat that is used to heat indoor spaces. Devices can target rooms, zones, or entire buildings. Heaters use different methods of heating a space (conduction, convection, or radiation) and use different kinds of resources to generate heat. Heating is typically not a primary concern for HVAC in data centers, but it is a critical factor, especially in cold climates where heat is required to protect components such as outdoor units and chillers. A comprehensive ventilation system is essential for an effective HVAC.

Ventilation is a separate mechanism from heating and air conditioning but works in tandem with both to maintain the airflow needed to effectively heat or cool a building. It also provides fresh air by replacing indoor air with outdoor air. Ventilation also plays a role in filtering the air and maintaining proper humidity levels, depending on the heating or cooling system. Adequate ventilation is especially important in data centers where air conditioning is used in conjunction with cooling the IT infrastructure. Depending on the device type and layout, data centers use different strategies for system ventilation and cooling.

HVAC systems contain specific equipment used to cool the circulating air. Approaches to cooling can vary greatly from commercial space to commercial space. For example, an air conditioner can be installed inside a building or outside, such as on a rooftop. You can also use water instead of coolant for temperature control. In addition, in conjunction with the ventilation system, they serve to filter the air and control humidity. Data centers rely heavily on-air conditioning to ensure that their IT infrastructure is functioning properly, and they use various strategies to cool and ventilate their systems.

HVAC Basics

Heating or cooling space is not the only purpose of an HVAC system. Instead, it improves indoor air quality and provides comfort for everyone in the building. There are many different types of HVAC systems, but they all start with the same basics. First, fresh air is supplied from outside or inside the house. This process is called aeration and is done in two different ways. Natural ventilation exists in most homes and refers to the normal way air enters and exits through windows, doors, vents, and other openings. This air exchange is necessary to replenish oxygen and remove odors, carbon dioxide, and excess moisture.

Mechanical ventilation uses a mechanical system (V in HVAC) to allow air to flow in and out. In the past, most homes had good natural ventilation from gaps and cracks during construction and door openings. However, modern architecture has produced much more enclosed homes, making ventilation an increasingly important factor in HVAC systems for homes. As air is taken in, it is drawn into the air handling unit where work begins. Here, the air is drawn through filters to remove dirt, dust, allergens, and other particles.

Next is convenience. Air is heated or cooled and excess moisture is removed. As soon as the air is clean, fresh, and at a comfortable temperature, it will be supplied to your home. For a central system, this means moving to another room through a network of channels and registers. In other systems, this usually means being led directly to the room.

How Does an HVAC System Work?

The three main functions of an HVAC system are interrelated, especially when it comes to acceptable indoor air quality and thermal comfort. Heating and air-conditioning systems are often one of the most complex and large-scale systems in your home, but it’s easy to tell when they stop working. There are nine parts to an HVAC system that you should familiarize yourself with: air circulation, filters, exhaust terminals, ducts, electrical elements, outdoor units, compressors, coils, and blowers.

Air Return:

Air return is part of the system that marks the beginning of the ventilation cycle. This return draws in air, pulls it through a filter, and directs it into the main system. Pro tip: Dirt and dust can easily accumulate on the filter, so be sure to dust it regularly.


The filter is the second part of the air return into which the air is drawn. Pro tip: Change the filters regularly to keep your system in top notch condition.

Exhaust Outlets:

Another part of the system is the exhaust outlet through which the exhaust gases produced by the heating system are discharged. Pro tip: Inspect chimneys and flues annually and adjust as necessary.


Ducts are that parts through which heated or cooled air flows. Pro tip: Clean the ducts every 2-5 years to keep everything in perfect condition.

Electrical Elements:

This part of the system can be tricky, but it’s often the first to run into problems. Pro tip: If anything isn’t working, check to see if the thermostat breaker has tripped or if the battery is dead.

Outdoor Unit:

This is probably the part of the system that comes to mind when someone mentions the HVAC system. A fan that provides airflow is located in the outdoor unit. Pro tip: Make sure the unit is free of dirt and vegetation, as vegetation can cause serious problems if sucked into the fan.


As part of the outdoor unit, the compressor converts the refrigerant from gas to liquid and sends it to the coils. Pro tip: If something isn’t working right, check your compressor. It is often the cause of many system failures.


Coils, which are usually part of the outdoor unit, cool the air as it flows, with the help of a refrigerant. Pro tip: Inspect the coil annually. If it freezes, you should check the filters and/or refrigerant level.


The fan draws warm air through the body of the unit. Pro tip: The more efficiently the air moves, the more durable the system will be.

Detailed Video on HVAC:

Video Explanation of HVAC

What is Included in an HVAC System?

Now that you know HVAC stands for Heating, Ventilation, and Air Conditioning, these are the three main components of the overall system.

  • Boiler or heating element
  • Piping systtem
  • Air conditioner

A heating element usually refers to an oven or boiler. Includes piping system for heat-carrying fluids, or tubing if using a forced air system. Aeration elements can be either natural or forced, and if forced, they are also primarily used for air purification purposes. As many of us know, the third and final element in the HVAC system is the air conditioner, the exact opposite of the heater. The main focus is to remove existing heat from inside the home.

Difference Between HVAC and Air Conditioning?

Surprisingly, we get this question a lot. So, what’s the difference between an HVAC and an air conditioner? Air conditioning is actually the last part of HVAC, but it is often used interchangeably with regard to any type of heating or cooling device in the home. Think of HVAC as one big term and air conditioning as one piece of the puzzle.


What does HVAC means?

HVAC stands for Heating, Ventilation, and Air conditioning

What is the difference between AC and HVAC?

The system that cools the air is the AC unit, and the system that heats the air and expels the moisture through the vents is called as a HVAC unit.

What is the purpose of HVAC?

The main purpose of heating, ventilation, and air conditioning (HVAC) systems is to maintain good indoor air quality and provide a comfortable temperature through proper ventilation through filtration.

What are the three main functions of HVAC?

The three main functions of heating, ventilation, and air conditioning are interrelated and specifically the need to provide comfortable temperatures and acceptable indoor air quality at reasonable installation, operation, and maintenance costs.

Is HVAC mechanical or electrical?

HVAC or Heating, Ventilation, and Air Conditioning is a part of the mechanical discipline.

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