If you’re like most homeowners, you probably know it’s essential to install an HVAC system in your home or office. This system ensures the indoor environment is conducive throughout the year to live or work comfortably. But have you ever taken the time to determine how the HVAC unit works? The truth is you aren’t the only misinformed one, but it’s advisable to know more to make sound decisions when buying or servicing an HVAC unit. This post will assist you to know what’s what.

What’s an HVAC Unit?

This piece of equipment is designed to heat, cool, and ventilate commercial or residential properties no matter if your home is using natural gas, propane, water, electricity, or home heating oil. When you get your HVAC unit, you are assured of having a comfy indoor environment and getting quality air. The system attains this by eliminating smoke, heat, moisture, odors, airborne bacteria, dust, carbon dioxide, and other harmful gases, controlling temperature, and replenishing oxygen.

How Do HVAC Units Work?

By now, you must be wondering how HVAC units manage to perform all these tasks simultaneously. The most crucial thing to understand is that the system moves air in or out of the building. As the warm or cool air is pumped into the house, it’s filtered to remove excess moisture, gas, and other harmful elements. To make sure your system works efficiently you must clean your HVAC regularly.

Below, we shall examine each sub-system and its function to make it easier to understand how an HVAC system works. Remember, the unit functions as a whole to provide good thermal comfort and indoor air quality regardless of the weather conditions outdoors. Some of the main parts include:

Air return

This HVAC component marks the beginning point of a ventilation cycle. It sucks air in, draws it via the filter, and delivers it into the main system. Returns need to be cleaned out regularly because dust and debris build up easily on the filters.


Although an air conditioner can still function without a filter, dirt and debris collect on the other components and damage them or reduce the unit’s efficiency. The quality of air supplied indoors would be poor too. So, ensure your unit has a filter, and change the part often.


Ducts are the channels that accommodate the cool or hot air as it passes through into the building. The ducts need to be cleaned occasionally to ensure you get quality air.

Exhaust outlets

This component is designed to expel the exhaust created by the HVAC unit. To ensure it functions optimally, you’ll need to check the vent stack or chimney flue yearly and tune it up regularly.

Outdoor unit

This component is probably what comes into your mind when an HVAC system is mentioned. It houses the fan that provides airflow and condenses the unit when it becomes hot due to the overheated refrigerant. Ensure debris and vegetation don’t accumulate on the outdoor unit as they can get sucked in and damage the fan.


This is the system’s control center, and its main function is to read the indoor temperatures and tell the unit when to turn off or on. It allows users to change temperature settings depending on their requirements.


Found in the outdoor unit, the compressor helps convert refrigerant from gas to liquid, then sends it to the coils.


Another component found in the outdoor unit cools the air with the refrigerant’s help. Coils need to be inspected annually, and when they freeze up, you should examine the filter or refrigerant level.


The component draws in warm air via the unit’s main section. It also works with the furnace, pulls air back for re-cooling, and circulates cool air into the building.


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