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How Does HVAC System Works?

    How Does HVAC System Works

    Your home or apartment has an HVAC system and you likely use it every day. With that being said, you may take it for granted. You don’t understand how it works and you may not care. However, there are many people who do. By learning more about HVAC equipment, you can enter an exciting career field, learn how to help others, and make decent money.


    How Does HVAC System Works 2024

    How Does HVAC System Works

    Do you know how your HVAC system works? If not, you’ve come to the right place. In this in-depth guide, you’re going to learn more about HVAC systems and how they work.

    Multiple Components

    At the end of the day, you have to understand that your HVAC system contains many moving components. This equipment works together to ensure that your home remains a comfortable temperature. It would be difficult to try to understand this equipment as a whole.

    Instead, you should try to gain a basic understanding of each piece. Once you’ve done that, you’ll understand what the equipment does and how it works together to power your HVAC system.

    Below, you’ll learn more about the HVAC components that are integral to keeping your home comfortable.


    Most homeowners only tinker with the thermostat. This equipment hangs on the wall. When you want to turn the system on and off, you use the thermostat. If you want to adjust the temperature, you’ll have to use the thermostat. You have to understand that the thermostat is responsible for sending messages.

    When your home reaches the desired temperature, the thermostat will know it and it’ll send a message to the other components. This will turn the HVAC unit off and ensure that it stops operating. Without a thermostat, you would not be able to control the system or it would operate around the clock.


    Now, not everyone will have a furnace. And, everyone that does have a furnace might not have the same furnace. For instance, there are oil furnaces available, gas furnaces, and even electric furnaces. That being said, most of these components work in a similar fashion.

    The furnace is the component that is responsible for creating the heat that drives the hot air into your home or building. Whether you have an oil, electric, or gas furnace will determine how exactly it does that. Gas furnaces work by drawing natural gas through a supply line. The gas is ignited in the system’s combustion chamber. The heat will then be released through the ductwork via a fan.

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    Oil furnaces pretty much work in the same manner. In fact, the only real difference is that it uses oil to create heat. The oil is pumped into the burner where it is combined with air and ignited to create heat. This heat is then dispersed throughout the ductwork via a fan.

    Now, electric furnaces are where things get a bit different. Instead of using gas or oil, they utilize electricity. This might be more expensive, but it does provide a cleaner type of heat since there are no fumes or combustion.

    Heat Exchanger

    The heat exchanger is the component of the system that is entirely responsible for heating the air before it is sent out through the ductwork. Only oil and gas furnaces will contain this type of component. An electric furnace will contain heat strips.

    That being said, the exchanger is a system of metal walls or coils that get heated via the heating element. Air is then blown through the heat exchanger either from outside or via a return duct. As the air travels through the exchanger it becomes heated and is then dispersed through the ducts.

    Blower Motor

    The blower motor was mentioned a bit above and it is without a doubt one of the most integral components of any system. Without this component, your system would be dead in the water. When your heat exchanger reaches a certain temperature, the electric blower motor will power on. This is a circular fan that looks like a hamster wheel. It spins and forces air through your home or building’s ductwork.

    When you feel air coming out of the vents, it is the blower motor that is forcing it out. When your thermostat reaches the desired temperature, it will tell the fan to shut off. The fan usually runs about 90 seconds after the call is read to turn it off. This allows the system to efficiently disperse all the hot or cold air in the ducts before shutting down.


    All systems will contain a condensing unit, but they may appear differently. If you have a furnace, you also have a condenser that sits outside. Some people will have an entire package unit outside where the condenser is housed. If you have a furnace your condenser will be separate.

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    And, that’s okay, it just means that it works a little differently. That being said, this component is part of the cooling system. It can also be part of the heating system if you have a heat pump, but that is where things get more complicated.

    The condenser cools the home by releasing heat into the outdoor air. If you walk outside on a hot day while the unit is running, you should feel hot air coming out of the top of the unit. And, this is the hot air from inside the home being pushed outside. This happens because it compresses and condenses the refrigerant from a warm gas to a cool liquid. While it is doing this the fan will be blowing air over the compressor to disperse this refrigerant.

    Evaporator Coil

    If you have a furnace the evaporator coil will be part of the indoor unit. This is where the condenser sends the cooled refrigerant. It is basically a coil of u-shaped tubes that get cool. In fact, this component works somewhat like the heat exchanger. The evaporator will house cool refrigerant and the fan will blow across the coil, sending the cool air into the home.

    The evaporator is basically a metal box located right on top of the furnace, usually, and gets cool. It works by evaporating the refrigerant in the heat, which causes the air to turn cold. This cold air is then forced through the duct system by the blower motor. While this is taking place, the refrigerant is being sent back out to the condenser to be cooled again.

    Refrigerant Lines

    The refrigerant lines are the ones that are entirely responsible for circulating the Freon throughout the system. If you have a split system with an inside furnace and outdoor condenser, you’ll likely see two refrigerant lines connecting the two. Even if you don’t see them, they are there.

    They carry the refrigerant to the condensing unit in the form of a gas and return it to the evaporator coil in a liquid form. These lines are usually round and can vary in size. They’ll vary from 3/8 to ¼ or ¾ to 5/8 or even 7/8, depending on the size of the unit. The bigger the unit, the bigger the lines.

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    You’ll find that most ducts are using for both the heating and cooling cycles of the system. This is not always the case, but it is usually the case with most modern systems. That being said, the vents that blow out the air in the home are attached to this ductwork. The ductwork is usually installed in the attic, basement, or walls.

    Each vent in the home or building is a branch that comes off the main ductwork. Think of the ductwork as a spider or an insect with six legs. Ductwork is similar, except it will contain more than 6 branches. These ducts are usually made of aluminum, although they can be effectively constructed of a variety of materials.

    Air Filters

    Speaking of return ducts, you are likely more than familiar with the air filter or filters. Most systems usually just contain one or two filters, but there are some systems that will house a return in every room with the supplies. These systems are unique, but they are out there.

    That aside, since the air is being recycled through the building or home, the HVAC air filters catch dirt and debris. In fact, that is what they are specifically designed for. They are designed to catch this dirt and debris before they get to the system.

    This helps keep the evaporator coil clean so that it will work more efficiently. Making sure that your filter is changed on a regular basis is one of the best ways to make sure that your system runs as efficiently as possible. Another way is to make sure that the condenser stays clean.

    Working Together

    Now that you’ve learned about these components, you’ll have a better understanding of how they work together. Whether you have a split system, zoned system, or duct-free system, each component is critical.

    If something goes wrong with one, you can guarantee that nothing will work as intended. So, you’ll need to hire a professional to fix the minor problem so your HVAC system can work as intended once again.

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