Key Components of Your HVAC System & What They Do

September 15, 2015


A basic knowledge of how your HVAC system works is important for better operation and maintenance.

st. louis thermostat

A good HVAC system ensures the comfort of your family throughout the year. It is important for every home owner to know the components of their HVAC system, and what they do to keep you cool in the summer and warm in winters:

Furnace: Your furnace is a key component of your HVAC system and very likely the largest. It occupies a lot of space and is usually placed in the basement, attic, cellar, or in a purpose-built closet. It supplies air that is distributed to different rooms in the home. It can use any of the four heat sources including combustion sources such as propane, natural gas, coal, oil, a heat pump, electric resistance, and solar energy.

Thermostat: In simple terms, a thermostat is the user interface that gives homeowners control over the temperature in their home. It is usually placed on the most accessible wall of the house. There are different types of thermostats available in the market including manual, programmed, and WiFi enabled thermostats. When the temperature drops or rises too much the thermostat triggers the evaporator coil and condensing unit or heat exchanger to start circulating temperature controlled air.

Evaporator coil: This is a component that cools the air when the thermostat is set to a lower temperature. It is generally placed in a metal box on the exterior of the furnace, and it performs the same function as an automobile radiator to generate cool air that is circulated throughout the house.

Heat exchanger: Your heat exchanger is located inside the furnace’s housing. It switches on when the furnace is triggered by the thermostat to generate warm air. It first pulls in cool air and heats it before circulating it via the ductwork.

Refrigerant lines: These lines carry a coolant to the condensing unit vaporized in the gas form and turns it into liquid form before sending them to the evaporator coil. These are narrow tubes made of temperature resistant metal such as aluminum or copper.

Condensing unit: This is connected to the evaporator coil and is installed on the outside of your home and filled with refrigerant. After the refrigerant is cooled into liquid form by a heat exchanger, the condensing unit sends the liquid to the evaporator coil so that is again evaporated into gas form.

Ductwork: The system of ducts that carry cool or warm air to the various rooms of the home.

Vents: These are the rectangular outlets transferring cooled or heated air from the ductwork to the individual rooms of the house. These are made of temperature-resistant material and are often located close to the ceiling. They usually have slats that direct temperature controlled air downward. These slats can be controlled or closed as required.

Some basic knowledge of what components make your HVAC system is important for its better operation and maintenance.

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