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How Does My HVAC System Work?

Your HVAC system is a sophisticated collection of intricately moving parts that work together to help keep your house comfortable all year round. Each part from the largest to the smallest has a unique function in cooling hot air. When you call the experts at USA Home Improvement, you're calling professionals who are 100% knowledgeable about how even the most complex HVAC systems work.

Your HVAC system controls the temperature, humidity, and air quality in your home. It's the system that keeps you comfortable whether the weather outside is cold or hot.

If you've ever been curious about exactly how AC systems work, check out the information below.

Parts of an HVAC system

Listed below are the main parts that make up your HVAC system.

Heat Exchanger

The heat exchanger is the part of the AC that heats the air that enters the furnace from inside the ductwork or from outside your house. Gas burners or electricity power the heat exchangers, and they use electric coils to heat the air.

Evaporator Coil

Your air conditioner's evaporator coil is responsible for cooling hot air that flows throughout your home. The coils start cooling when the temperature inside the house begins to get warm. The evaporator coils then send the chilled air through the furnace blower and into the ductwork, where it cools the space.


The furnace is the part of your HVAC system that pushes heated air throughout your space. Your furnace is probably hidden away in your basement, attic, or utility room. The furnace can run on several different types of heat sources, including oil, gas, or solar power.

Condenser Unit

The condenser unit is located on the outside of your house, and it holds the refrigerant gas that's been cooled. When the gas has been compressed, it's turned into liquid. That liquid then moves from into the evaporator coil, where it cools the air.


The vents are responsible for sending the air from the HVAC system into the different rooms of your house. They are usually wood or metal.


The thermostat is responsible for managing the temperature inside the house. Sensors throughout the house, along with the thermostat, tell your HVAC system to either heat or cool the air. You can manually operate the thermostat or program it to function automatically.

Refrigerant Lines

The HVAC unit's refrigerant lines are responsible for taking liquid back and forth between the condensing unit located outside the house and the furnace situated inside the house. These lines are usually copper or aluminum.


Your HVAC system's ductwork is responsible for distributing air throughout the system as well as your house. It's located in your walls or ceilings.

Types of HVAC Systems

There are several types of HVAC systems to choose from:

Duct-free split HVAC unit: This type of system doesn't use ducts. It's a good option for homes that don't have ducted heating systems or for rooms that can't accommodate ductwork.

Heating and air conditioning split system: This is the most common type of HVAC system, and its parts are located both inside and outside of your house. The AC portion of the unit chills refrigerant on the outside of your house, and the furnace works with a fan and coils on the inside of the home. This system's ductwork carries air throughout the house, heating or cooling it.

Zoned HVAC system: With a zoned HVAC system, you can cool down or heat up different areas of your home by manipulating dampers within the ductwork. The dampers, or valves, can block airflow according to how you set them. This system allows you to control airflow and heat or cool specific areas.

Knowing exactly how your HVAC system works can help you keep it in good condition. And you'll have a better idea of what's going on when something goes wrong. If you have any questions or concerns about your HVAC system, reach out to the specialists at USA Home Improvement at 844-468-7244. They can help ensure that your HVAC system continues to run smoothly.