What is HVAC system, and how does it work?

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HVAC systems have now been vogueing in recent times and are also still steadily gaining a lot of popularity not just in households but also in commercial spaces. While HVAC systems are now one of the most commonly used systems, only a few actually know what they are, how to operate them, or how they differ from standalone heating systems, air conditions or ventilators. So here is a brief description of what HVAC is and the uses of HVAC.
Well, if you look at HVAC, it is nothing but an acronym that stands for Heating, Ventilation, and Air Conditioning Systems. Its main function is to regulate thermal comfort and air quality, which are essential for human beings’ survival. With three different parts to it


During the cold weather, it is quite hard to control the temperature. Heating however is a process where you can get to heat the interiors of your house during really cold weather. This is done by increasing the temperature with the help of systems such as HVAC. The cold air present in the room is removed and the system tends to blow the hot air which tends to heat up the place.


Ventilation or ventilating is referred to as the process where you exchange or replace air in any space such that you get high indoor air quality. This process also helps you to get great temperature control, oxygen replenishment, and removal of various unwanted moisture, smoke, heat, dust, and airborne bacteria from your place. Ventilation is also a great way to remove any bad odour from your home and keep good air circulating continuously in the house.

Air Conditioning

Air conditioners are a device where they help cool down the temperature of your space while also removing heat. It also helps to remove humidity from the space which makes it more comfortable to stay in the space. While people mostly get air conditioning through standalone air conditioners, there are also systems such as HVAC systems that consist of integrated AC systems that allow reverse valves to control both heat and coolness of the space.

Components of HVAC systems

A complete HVAC system is an entire system that consists of more than one component. In fact, there are multiple units and parts both outside and inside of your home that all work together to ensure the complete home comfort that you require. While there are a lot of components in the HVAC system here are a few of the ones you are most likely to come across in the system along with what these components of HVAC system do.

Heat Pump

Unlike its name, a heat pump is a device that can both heat and cool your home. They tend to use refrigerant to absorb, transport, and release heat. They can also help reverse the flow of refrigerant based on whether you need to heat or cool the area. Heat pumps are mostly powered by electricity and not fossil fuels.  

Air conditioner

Air conditioner tends to cool your home by removing out any excess humidity from your house and transferring it outside.


Furnaces help create heat by burning a fuel source, which is mostly either propane or natural gas. The heat they create is also distributed evenly throughout your home, and this is done so that the indoor temperature can be increased.


Ductwork is a system of pipes which are also called ducts that help carry and distribute air from units such as air conditioners, furnaces, and heat pumps.


The thermostat which is present inside your home allows you to control your indoor temperature. When you change the temperature on your thermostat it signals to the rest of your system that your home needs to be either cooler or warmer.

Air handler

Air handlers are the ones that circulate both cool and warm air formed by other HVAC units throughout your entire home so that the desired temperature can be easily reached in every home.

Common uses of HVAC systems

The HVAC is more than just any upscale or fancy air conditioner that you install in your house. It consists of multiple functions such as ventilation, heating, and AC all in one system. This has led to multiple uses of HVAC systems right from residential to commercial uses of the same. Here’s a brief account regarding the same.


As far as residential use is concerned, you get to keep your home cool during the warmer months while you get to keep it warm during the cooler months. This system also finds their presence ubiquitously, gracing homes and even confined spaces while also ensuring there is optimal environmental comfort. One of the best parts of using HVAC systems for residential purposes is that they allow better quality air without having to compromise on the bill part.


Commercial buildings often require strong ventilation, heating, and air conditioning systems so that they can maintain comfortable temperatures across large spaces. While the residential units tend to cool single homes, office properties need quite heavy-duty-based equipment that has a capacity of hundreds of tons. Building owners must carefully evaluate the different options of HVAC systems before they select one that fits the needs of the building.


Industrial HVAC systems are used in any facility that requires cooling down, warming up, or improved flow of air. Typically there are one or more units that are attached to your facility to provide an efficient cooling or warming effect. These units are also coupled with a ducting system that helps process the air and distribute it equally to all of the facility.  An additional benefit of attaching such a system is that it allows positive pressure within the building, hence reducing the amount of air that is contaminated entering the facility.

How Does an HVAC System Work?

The operational principle of an HVAC system tends to involve the intake of fresh air from the surroundings which is then cooled or heated before they are again circulated throughout the indoor spaces. This may also include an individual room or a big building such as an educational institution, airport, house, or even an office.

An inclusive HVAC setup consists of both a heating and a cooling unit along with a duct system designed to convey air that has been either cooled or heated. Now, let’s take a look at the functions of each unit individually.

Heating process

HVAC consists of heating processes such as convection, conduction, and radiation while using equipment such as heat pumps and boilers. This is important, especially in cold climates, for survival or for the various temperature conditions required. The system also consists of various components such as heat pumps, boilers, or furnaces that help generate warmth for either the entire structure or for a particular zone. This again requires resources such as propane, electricity, natural gas, or heating oil that will help the equipment to work.  

There are various types of heating systems, such as follows:

  • Forced air systems – Forced air systems transfer heat into the air, and this air is then transported throughout the house. The system is mainly operated with the help of an electric furnace and requires the burning of fuel oil, propane, or natural gas.
  • Radiant heating system – Radiant heating systems are often also called hydronic heating systems because they have to heat water to produce heat. This boiler then pushes off the hot water through a system of radiators, which eventually heats the air in each room.
  • Geothermal heating system – Geothermal heating systems are those which consist of geothermal pumps that draw in heat from a nearby water source or from beneath the ground. These systems are more efficient than other pumps and require minimal electricity to operate.

Ventilation process

In HVAC, the ventilation system helps maintain clean and consistent airflow, whether outdoors or indoors. It also collaborates with the cooling and heating systems to ensure proper temperature control. Bringing in fresh air from outdoor areas ensures proper air quality, too. It is, however, important for effective HVAC systems to help in humidity control and air filtration. HVAC systems are most commonly seen in places such as parking garages, where the systems clear out carbon dioxide gas by using large fans. In places where there are large amounts of IT equipment, ventilation works along with cooling systems to maintain an ideal temperature.

The types of ventilation systems seen commonly can be provided as follows:

  • Natural ventilation – This refers to the ongoing supply of air from a natural source, which is actually one of the most ideal ways to get fresh air within a building. These, however, depend on natural forces such as thermal buoyancy and wind pressure to drive the air throughout the building.
  • Mechanical fan ventilation – Mechanical fan ventilation consists of fans installed directly into the windows or into the air ducts of the building to help conduct air either towards the inside or to the outdoor area. This provides the building with internal air that is extracted through the fan in a controlled manner.
  • Smoke ventilation – In public buildings, it is one of the important criteria to attach a smoke ventilation system which helps mainly during an event of fire. This also allows to removal of the thick build-up of smoke in the building if there’s a breakout of fire.

Air Conditioning process

HVAC also consists of the third system which is nothing but the air conditioning system. This is one of the important systems, especially in hot and humid weather. In such scenarios, effective ventilation is required, along with proper cooling effects. Water could also replace coolant to help with temperature control. Data centres such as IT companies rely heavily on IT operations via ventilation and cooling.

  • Central AC – Central AC is a type of AC that consists of only one central source of cooling, which is distributed to every part of the house with the help of ducts. These types of AC units tend to consist of an evaporator coil that absorbs all of the heat from the air in your house.
  • Portable AC – A portable AC is one of the standalone pieces of equipment that is portable and can be used indoors to air condition a place. To ensure proper working, exhausting warm air out of the space is important.
  • Split AC – These split AC units help cool or heat the house with no ductwork being involved and are one of the most efficient ways to cool the house. While split AC can be put throughout the house, they are only attached to a room where ventilation and cooling are especially needed.

Types of HVAC Systems

HVAC systems consist of two categories such as ducted or ductless. In a ducted system, there is the presence of a main unit that pushes the air through the series of ducts to cool or heat the building. In the case of ductless, however, lacks air ducts and uses alternative methods to distribute equally throughout the space. Here are a few other types of HVAC systems that are commonly seen.

Split systems

Heating and cooling split systems are two of the most commonly used types of HVAC systems that are used in residential buildings. They also consist of two separate components, one used for heating and the other for cooling. There is only a single thermostat that controls the temperature for the entire structure. The heating system in this type is gas-powered and tends to use an evaporator to push the heat through a building’s duct system. The cooling system, on the other hand, uses the coils, compressors, and refrigerant to cool air, and there is a fan that directs the hot air out.

Hybrid systems

A hybrid split HVAC system has the same cooing unit and structure as that of the split system however does not only rely highly on gas to create heat. While its heater can burn gas, it can also utilize electric power. Electric heating however is often slower and is less powerful than compared gas-powered options. One of the main features of this type is that it reduces energy consumption.

Duct-free systems

Duct-free systems as the name indicates do not consist of ducts to transfer the air. These units consist of a compressor, condenser, refrigerant, and an indoor air handling unit. While they could be expensive to install however they often help reduce energy costs and consumption over time.

Packaged systems

Packaged cooling and heating systems are not as common as the split system but the small size of these systems is what makes them better for small areas where there is not much space. The cooling and heating components are placed in a single unit and generally stored in the attic space or near the building’s foundation. Also since there is only a single unit, it is easier to maintain.

Maintenance and Care of HVAC Systems

Paying for the bills utilized by the HVAC systems might be high. However, you do not need to spend extra if you ensure proper maintenance and care are provided to your HVAC systems. Dirt and neglecting the system are what causes inefficiency and system failure most commonly. This again leads to extra expenses, which you definitely do not need. Here are a few ways to take care of your HVAC systems:

  • Ensure that you get annual pre-season checkups so that your system is ready before the season starts.
  • Inspection and changing of air filters will help reduce energy costs and also save your systems from failure.
  • Installing a smart thermostat is also one of the ways to automatically adjust the cooling and heating temperature settings for better performance.

Choosing the Right HVAC System

Choosing the right HVAC system for you highly depends on a lot of factors, such as where you live, the size of your home, the price range, and more. The best HVAC system also depends on your comfort preferences, such as whether you require a system that is energy efficient or quiet or one that can control humidity. Based on these factors, it is easier to determine which type of unit will be the best for you.


Well, now you know exactly what is HVAC what are the components of HVAC systems and how they work. This brief explanation is sufficient for you to understand which one is the perfect unit for your home. Having separate units for heating, cooling, and ventilation may seem way too expensive. This is why most people tend to opt for HVAC systems that have all the necessary requirements in a single piece.


What is the difference between AC and HVAC?

The main difference between an AC and an HVAC is that the HVAC consists of three functions such as heating, ventilation, and air conditioning. Whereas in an AC there is only one function which is cooling the air.

Is HVAC only for AC?

No HVAC is a system that does not only work for AC but also for other functions such as ventilation and heating.

What is an HVAC system in a building?

The HVAC system installed in buildings is a type of system that helps with cooling, heating, and ventilating air functions.

What is an HVAC engineer?

An HVAC engineer is one who installs the system and helps service it while checking the air quality and temperature systems.

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