HVAC Breakdown Repairs

How Does A Commercial HVAC System Work?

Understanding your commercial building’s HVAC system is an important detail for many reasons, not the least of which is keeping the system humming along, so you aren’t stuck baking in the summer when something goes wrong, costing time and money. Today, we’ll explain some details about commercial building HVAC systems, how they work, what to expect for maintenance and more. 

In order to control the environment inside your commercial or industrial facility, you need a commercial HVAC system. This type of equipment is specifically designed to handle the complexities of a large-scale operation heating and cooling. Therefore, it’s important to understand how commercial HVAC systems work to help you choose the right one for your needs.

Although the core principles of refrigeration remain the same, cooling a large building is a challenge.

The bigger your building is, the more opportunities there are for waste. For example, a large building may have hundreds of feet of ductwork, and clogs can develop anywhere within that sub-system. That, in turn, impairs airflow, reduces HVAC results, and makes the system work harder. Looking for Commercial  HVAC Melbourne? Look no further, Outline Air Melbourne has you covered.

With that in mind, greater square footage increases the maintenance needs of the entire HVAC system. It is also more important that the system be planned and installed correctly. It must not only meet today’s needs but be operated to maximize efficiency in the long term.

What is an HVAC System?

HVAC Commercial Domestic Air Conditioning Solutions
HVAC Commercial Domestic Air Conditioning Solutions

HVAC stands for Heating, Ventilating and Air Conditioning. HVAC systems help to control the temperature, humidity and air quality within a building to provide a comfortable environment.

First and foremost, HVAC stands for heating, ventilation, and air conditioning. This system provides heating and cooling to residential and commercial buildings. You can find HVAC systems anywhere from single-family homes to submarines, where they provide the means for environmental comfort. Becoming more and more popular in new construction, these systems use fresh air from outdoors to provide high indoor air quality. The V in HVAC, or ventilation, replaces or exchanges air within a space. This provides a better quality of air indoors and involves removing moisture, smoke, odours, heat, dust, airborne bacteria, carbon dioxide, and other gases, as well as temperature control and oxygen replenishment.

So now that you know what they are, the next question is: how do they work?

The heating aspect of an HVAC system is produced by using radiators or supply air systems within the commercial building. Ventilation is accomplished by extracting contaminated air out of the building while maintaining clean air. It also circulates the internal air and removes any excess humidity. Mechanical systems like fans are typically used during ventilation. Finally, cooling systems lower the temperature and help maintain proper humidity levels within the commercial building.

What Is A Commercial HVAC System, And How Does It Work?

Heating, ventilation, and Cooling systems, otherwise known as HVAC systems, are an integral part of modern buildings. HVAC systems are in charge of keeping temperatures comfortable (usually around 72 degrees), humidity consistent (between 40-60%), and indoor air quality high (keeping C02 to less than 1000PPM). 

There are several different types of commercial HVAC systems, but in general, these systems operate similarly:

  • Air conditioning units lower the temperature by passing air through refrigerant or water-cooled systems, also removing excess moisture from the air in the process.
  • Heating systems essentially work opposite to air conditioning/cooling systems, where air passes through systems that heat the air using water, radiator coils, or gas.
  • Ventilation systems keep the air clean by circulating air with fans and passing air through filtration systems.

Commercial HVAC systems in buildings contain interconnected systems that provide heating, ventilation, and cooling to individual floors or other areas within the structure. Commercial HVAC systems usually include heat pumps that extract heat from the air or water for heating purposes. Water source heat pumps contain pipes that carry water throughout the building. Rooftop units are typically on the roof of the building, but they may also be on the ground. They work to put the conditioned air into the building. Chillers generate cool water that is distributed by pipes to air cooling coils. Heaters within commercial HVAC systems come in two different types: Radiant heaters that utilize infrared radiation and furnaces that burn fuel to heat the air within the structure.


As the heating system engages, combustion gases are created by the system’s burners and moved into a heat exchanger. The air from within your commercial space is blown across the heat exchanger, where it is warmed before being dispersed through your ductwork to various parts of the building.

For HVAC systems with furnaces, the thermostat will start the heating process by signalling the furnace. Next, a gas valve within the furnace will open to ignite the gas burner. Next, the heat generated from the burner is then used to heat the heat exchanger. The heat is then transformed into the air as it flows through the exchanger.

Once the heat is turned into air, it is distributed using an internal motor and fan attached to the furnace. Finally, the heat is sent through the ductwork located throughout the commercial building.


Ventilation is a necessary component of any HVAC system, allowing fresh air to enter your commercial building and contaminated air to exit. In the absence of adequate ventilation, the indoor air would become stale, odours would linger, and there would be a higher rate of mould and mildew growth. In addition, harmful byproducts created during the combustion process are vented to the outdoors through flues and vent pipes. At the same time, fresh air is circulated to remove particulates and remove excess moisture.

HVAC systems would be pointless without proper ventilation. Ventilation allows the correct amount of fresh air to enter your commercial space, regardless of heating and cooling procedures. Without this fresh air, you could be subjected to odour, mould and other contaminants in the air.

It works by releasing harmful contaminants created during the heating and cooling process via flues and vent pipes while allowing new air to enter in a controlled manner.


Air conditioning utilizes the process of refrigeration to cool the air by removing the heat from it. In addition to lowering the air temperature, this process also serves to maintain appropriate levels of humidity, using a water-cooled or air-cooled system.

Air conditioners within the HVAC system will use refrigeration to cool the air. First, refrigerants or substances used to absorb the heat start in a gas form. Next, a compressor is used to compress the gas, raising the temperature.

Once the gas is properly pressurized, it is transferred into a condensation coil, releasing the heat and changing the gas into a cooler liquid. Finally, a blower takes in the warm air and releases it over an evaporator. The liquid becomes a cooler gas again, absorbs the heat from the air and effectively cools it.

Air Return

Your air return is the part of your system that marks the starting point of the ventilation cycle. This return sucks in air, draws it through a filter, and then passes it into the main system. Pro tip: Make sure to dust your returns frequently, as debris and dust can easily build up on your filters.


Your filter is the second part of the air return through which the air is drawn. Pro tip: Make sure to change your filters regularly to keep your system in tip-top shape.

Exhaust Outlets

Another part of your system is the exhaust outlets, where the exhaust created by the heating system is expelled. Pro tip: Check your chimney flue or vent stack annually and tune it up if necessary.


Your ducts are the channels through which the heated or cooled air passes. Pro tip: Get your ducts cleaned every 2 to 5 years in order to keep everything in working condition.

Electrical Elements

This part of your system can be a bit trickier, but often problems originate here first. Pro tip: If something isn’t working right, check for a tripped breaker or dead batteries in your thermostat.

Outline Air Pipes
Outline Air Pipes

Outdoor Unit

This is likely the part of your system you think of when someone mentions an HVAC system. The outdoor unit houses the fan, which provides airflow. Pro tip: Keep your unit clear of debris and vegetation as it can cause serious problems if plants are sucked into your fan.


As a part of the outdoor unit, the compressor is responsible for converting refrigerant from a gas to liquid and sends it to the coils. Pro tip: If something isn’t working quite right, check your compressor. It is often the cause of many system failures. Check out our range of Domestic Air  Conditioning Melbourne to help with your problem. 


Usually, another part of the outdoor unit, coils cool the air as it passes through with a little help from the refrigerant. Pro tip: Check your coils annually. If they freeze up, you may want to check your filter and refrigerant levels.


The blower draws in warm air through the main section of the unit. Pro tip: The more efficiently this air moves through, the more durable your system will be.

What Are The Different Types Of HVAC Systems?

If you’ve looked into replacement, repair, or maintenance of your buildings’ HVAC system, you’ll know that there are an overwhelming number of combinations of different types of systems. While this is true, all of these various types fall into 3 main categories:

Single Split System 

This is the most popular and affordable type of HVAC system, found most commonly in smaller commercial buildings. These systems allow individual control of the heating and cooling for each space, making it ideal for offices with server rooms or restaurants. 

This popular, affordable option is ideal in smaller commercial applications such as a restaurant, storefront, or small office configuration. A single-split system allows for individualized heating and cooling control for each room, and in larger areas, they can work together to control the environment.

This system will likely be configured to include an air conditioner, furnaces, and an evaporator coil. In addition, it can be controlled using a thermostat or a direct digital control (DDC) system.

These systems typically include air conditioners that pass air by refrigerant lines and furnaces in one system that circulates air throughout the space via air ducts. The drawback of single split systems is that for each space you wish to control separately, you’ll need an outdoor unit – taking up precious space.

Multi-Split System 

Multi-split systems operate similarly to the single split system but offer much higher energy efficiency and a much smaller outdoor footprint. Multi-split systems allow you to connect up to 9 indoor units to one outdoor unit. These systems also include sensors that detect temperature changes and can adjust as needed, consuming far less energy. 

Heat pumps in this type of system are also designed to move air to work with the natural flow of warm air into cool areas, saving money and energy. However, these systems do require more installation time, so the cost of installation can be higher.

VRF and VRV System 

VRF (variable refrigerant flow) or VRV (variable refrigerant volume) systems are best for larger mixed-use type buildings, such as larger office buildings or hotels. 

A variable refrigerant flow (VRF) or variable refrigerant volume (VRV) system utilizes either heat pump or heat recovery technology. A heat pump system provides either heating and cooling, which may be beneficial for large open areas. In contrast, a heat recovery system can provide both heating and cooling simultaneously and is ideal in applications where the space is divided into multiple rooms.

Heat Recovery VRF systems can provide heating and cooling to different spaces at once, using warm air “waste heat” from areas of the building and delivering it to where heat is required, especially great for buildings with lots of smaller rooms. Heat pump VRF systems deliver either heat or cooling and are best for larger open areas. 

What Is Included In An HVAC System?

Since we now know that HVAC stands for heating, ventilation, and air conditioning, we know those are the three main parts of the entire system.

The heating element usually refers to a furnace or boiler. It includes a pipe system for the fluid carrying the heat or ductwork if you’re working with a forced-air system.

The ventilation element is either natural or forced, and when it is forced, it is more often than not used for air cleaning purposes as well. Our exclusive range of services for HVAC Maintenance will help you in many services, including Installation, or Maintenance, or Service & Repair.

As many of us know, the third and final element of an HVAC system is air conditioning which is the exact opposite of heating. Its main focus is to remove the existing heat from the interior of the home.

How Long Do HVAC Systems Last?

In a world of constantly changing technology, as well as changing environmental conditions both indoors and out, HVAC systems require different kinds of care – and you may be tempted to upgrade more frequently. 

Now that you understand exactly what an HVAC system consists of, you’re probably wondering how long a new one will last you. Of course, this really depends on the equipment to know how long the system will last. But, if you keep up with your recommended annual maintenance, your equipment will last you for years and years to come. 

The current commercial HVAC units should last 10-15 years. Some of the factors that impact the longevity of your HVAC include:

  • Usage demand over the years; climate of your area
  • Quality and efficiency of the system
  • Proper installation and maintenance


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