How Does An HVAC System Work | The Different HVAC Systems

HVAC Controlling Heat

Most homeowners consider when it comes to the heating and air conditioning of their houses that it should keep them and their families warm in the winter and cool during the summer season.

This is where the HVAC system helps out. A sound HVAC system helps you provide thermal control and indoor comfort for you and your loved ones.

Does HVAC control heat? Yes, HVAC, which stands for heating, ventilation, and air conditioning, controls the operation of all the heating and air conditioning systems. It regulates heat, but it also helps to keep your indoor spaces cool during the summer season.

This article will discuss all the basics of an HVAC system from different parts that help regulate the heating and cooling of your indoor spaces. It will also discuss the different capabilities in terms of heating, ventilation, and air conditioning systems.

What Is An HVAC System?

Heating, ventilation, and air conditioning system, a system intertwined that provides heating and cooling to many residential and commercial buildings.

You can easily spot HVAC systems anywhere from single-family homes to many submarines where necessary environmental comfort is required.

In addition, HVAC systems became more popular in the construction field as these systems use fresh air from the outdoors to provide high-quality indoor air.

The V in the HVAC system stands for ventilation, and it is the process of replacing or exchanging air within its allocated space.

This will eventually provide better quality for many breaths of air indoors, and it involves the removal of different smoke, odors, heat, dust, moisture, airborne bacteria, carbon dioxide, and other gases.

How Does An HVAC System Work

An HVAC system has three main functions related to one another. It is especially true when providing better indoor air quality and thermal comfort.

Unfortunately, your heating and air conditioning system is usually one of the most complicated and extensive systems in many residential and commercial spaces.

This is why when it stops working, you will know soon enough, and this is where you need to be familiar with different parts of the HVAC system.

So here are the essential parts of your HVAC system that you should be familiarized with in case of an emergency that needs to be taken care of:

Heat Exchanger

The heat exchanger is the part of the housing for your furnace, and it basically just absorbs all the heart and warms cool air when your thermostat activates your furnace.

The heat from combustion will arise, and all types of furnaces have heat exchangers, including your electric units. Therefore, it is among the most critical components that need solid stainless steel with temperature-resistant alloys.

These temperature-resistant alloys will prevent all cracks and other damage, and some modes actually have a special duct to let cool air enter the heat exchanger faster.

If you happen to have a problem with your heat exchanger, it could lead to a carbon monoxide leak which can cause headaches or even death.

Air Return

Air return is the part of your HVAC system that marks the starting point of the overall ventilation cycle. This return sucks in air, and it draws it through a filter and then passes it into the central HVAC systems.

It is always recommended to dust your returns frequently as some debris and dust can quickly build up on your filters.


Speaking of filters, your filter is the second part of the air return through which the air is drawn. Always make sure that your filter is cleaned or changed regularly to keep your system in good condition.

Exhaust Outlets

Another part of your HVAC systems that you need to know is the exhaust outlets. The exhaust was created in the exhaust outlets, and it is being expelled by the heating system.

Many professional HVAC technicians recommend constantly checking your vent stack annually to ensure everything is all good and perform a tune-up if necessary.


Ducts are known to be the channels through which the heated or cooled air passes. Many recommend that the ducts be cleaned every 2 to 5 years to keep everything in good working condition.

Electrical Elements

This part of your HVAC system is where it gets tricky, and most of the time, all problems originate here. If something is not working right, check for a tripped breaker or dead batteries in your thermostat.

Outdoor Unit

It is the part of your HVAC systems you think of when someone mentions an HVAC system. The outdoor unit is the one that houses the fan, which can provide airflow.

If you want to maintain it properly, you need to keep it clear of debris. Check also if there is any vegetation around it as it can cause severe problems if plants are sucked into your fan.

Condenser Coil Or Compressor

Your compressor or condenser coil is a part of your HVAC system that is installed outside your home. A condenser is the one responsible for cooling your home by releasing heat into the outdoor air.

This phenomenon happens when the condenser coils compress and condenses the refrigerant from a gas state to a cold liquid state.

Simultaneously, a fan will blow over the compressor to disperse the heat and cool the refrigerant faster. Finally, the HVAC system will send the liquid refrigerant through an aluminum or copper line to your evaporator coil.

Evaporator Coil

The evaporator coil is among the essential parts of your HVAC system, and it can be found inside your system indoors air handler.

Your HVAC system will bring refrigerant to a series of small nozzles, and then these nozzles spray the liquid refrigerant for the substance to quickly evaporate into a gas.

This will absorb heat and then lower your home’s temperature so you can enjoy your coy indoor spaces.

On the other hand, heat pumps work like air conditioners, and they have the same parts. They are usually responsible for reversing the process of heat transfer during winter to bring heat from outdoor air to your home and get rid of the cold air.

However, using heat can make your air dry, and it can irritate your skin and eyes. This is where the humidifier will come in handy to make your home more comfortable and prevent all these problems.


A thermostat is a defining factor that can sense when your heater or air conditioner will turn on and off, and it can serve as the control for many HVAC users.

It is mainly connected to your entire system through different wires, and usually, people place their thermostat near the center of your home.

Many heating and air conditioning systems have more than one thermostat, and each thermostat can control different zone areas.

This can help you save energy by only heating or cooling a small portion of the occupied area, and all members of your household can choose the temperature that is comfortable for them.

In addition, having a programmable thermostat can help you set your thermostat to change its temperature automatically. This can save you money, time, and energy, and some models can even set a different schedule depending on the day it is.

Blower Motor

Right after the air in your heat exchanger reaches a standard temperature, your electric blower motor will now power the fan that can force the warm air into your home’s ductwork and in all the rooms in your home.

It is where combustion ends before the blower motor ceases to work, so all the warm air in your ductwork and heat exchanger will get to the rooms of your home before the motor shutdowns.

A variable-speed blower motor can actually run at different speeds to control the flow of air around your indoor spaces.

It is the one responsible for monitoring your HVAC system and compensating for different problems. Since most variable-speed blower motors can reach total speed capacity, they are not as noisy, and they can quickly lower your humidity more effectively during the summer.

Combustion Chamber

Oxygen is needed to achieve proper combustion, and your furnace adds air to fuel what is inside a combustion chamber.

The heating cycle will start when a small amount of air and gas mixture enters the combustion chamber for many gas furnaces. The glow stick or a pilot light will ignite the mixture, and it will burn in a controlled fire as more gas and air move inside the burner.

A glow stick is actually an electronic ignition system, while a pilot light can act as a tiny tube that constantly releases a small amount of gas as fuel for the flame. Glow sticks light automatically, but many homeowners have to relight pilot lights if they go out. Also, many older furnaces have pilot lights because they need to use more gas than glow sticks.

The Different Systems Of An HVAC System

HVAC is a primarily used term in the heating and cooling industry, and it stands for heating, ventilation, and air conditioning.

These functions are usually combined into one system in many modern homes and commercial buildings.

The ulterior goal for an HVAC system is to provide thermal comfort and acceptable indoor air quality, whether it’s cool or warm air. All cooling and heating systems have three essential components:

  1. A piece of equipment that is responsible for removing and adding heat to the air
  2. A machine that can distribute the air in every place in your home
  3. A controlling device that can easily manipulate your temperature

Both air-conditioned cool air and warm air coming from your furnace often use the same distribution and control to your HVAC systems.

Although having an HVAC system might be complicated, breaking the system down into its core component can help it to simplify a little bit.

Air Conditioning

Air conditioning is responsible for making your home cooler, and this is by drawing heat energy out of the house and then transferring that outdoors.

In hotter states like Colorado, the most common residential central air conditioner is a split system. There is an outdoor metal cabinet that is mainly placed on a concrete slab next to the foundation.

It contains the condenser, the compressor, and the condenser fan, and having an indoor cabinet only contains the evaporator.

The compressor is responsible for pumping the heat transfer liquid, and it is typically a Freon refrigerant between the evaporator and the condenser.

The liquid refrigerant will then evaporate in the indoor evaporator coil and pulling the heat out of the indoor air. Next, the air handler in the furnace is used to blow the cooled air through your home duct system.

When the blower starts to run, it draws room air from different parts of your house through air ducts.


The furnace is responsible for pumping cooled air throughout your home in the summer and hitting your home during winter.

Most air conditioners are powered by electricity, but some furnaces are being fueled by natural gas. If you look into a home furnace, you will notice that it is divided into three parts:

  1. The first one is the burner, heat exchanger, vent, and draft inducer.
  2. Safety controls and devices
  3. Blower

All of these parts work together to be able to keep your furnace running effectively and efficiently.

The heating process begins when your HVAC system combines air with fuel, and the electronic igniter sparks the mixture.

Next, most of the hot gas will begin to rise through the heat exchanger, usually positioned above the burner. It will then heat the air, which is circulated throughout your house.

Next, an electric fan is situated inside the furnace, and it pulls in air. This will come through a large grill that is typically located on the main floor of the house.

Before air gets into the furnace, it goes through the furnace filter to remove dust and other different particulates. The exchanger then hears the air that is very quick as a result of high-temperature flue gas.

The hot air will then be forced out of the furnace and through the ductwork into your home’s indoor area. The resulting flue gas usually used to create heat is now vented through the vent piping, and then it will be discharged through the outside wall or roof.


Ventilation is one of the most critical parts of the HVAC system, and it is known to provide proper ventilation in your home for comfortable and healthy living spaces.

It is a combination of processes for exchanging and replacing the surrounding air in a confined space. Natural ventilation is known to be when the air enters your home through doors, windows, and skylights.

Mechanical ventilation uses some devices like exhaust fans, which are responsible for exhausting air out of your house in specific locations.

On the other hand, the HVAC system uses air ducts to provide a balanced airflow system throughout your indoor living spaces.

Another more balanced ventilation system is HRV, the Heat Recovery Ventilator, ERV, Energy Recovery Ventilator. Both of these draw in outside air and exhaust room air through a system that exchanges heat.

These systems are great for newer efficient homes that have good windows, doors, and insulation. The result is efficient ventilation control and more oxygen replenishment, and the removal of moisture, odors, smoke, heat, dust, and some airborne bacterias.

The Thermostat Controls It All

The thermostat is the brain that is behind your HVAC equipment. Although most homeowners might not know the inner workings, they do know what controls it.

Even the most straightforward HVAC thermostat is generally composed of an external switch that can control the heat, cool, or shut it down completely.

For example, some designs have an on/auto switch that can turn the blower fan on constantly when heating or cooling is running.

Nowadays, there are many electronic and programmable thermostats, becoming more common in today’s modern home.

This features multi-day settings, multi-period settings, hold, override, and even a furnace filter change reminder.

In addition, even newer models are equipped with Wi-Fi ability and technology that allows you to control your thermostat using any devices such as your laptop, smartphone, and tablet.

Having a programmable thermostat will be able to keep your HVAC system optimized. If you have an HVAC system that is a little bit older and questioning its efficiency, it might be time to pair it with some programmable thermostat.

It will reduce the workload of your system, and it helps your system work at its finest.


To sum it up, besides heating, ventilation, and air conditioning, many smaller components make up the best HVAC systems. All of these are actually important to keep your system working efficiently and correctly.

Ensure to have an annual check-up to keep your system at peak performance, and it can lower HVAC system cost over time.

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