Written by Columbia HVAC

Back to Basics: How Does My HVAC System Actually Work, Anyway?

HVAC systems may seem like confusing and complicated pieces of machinery, but it’s worth getting to know how these important systems work in your home. You’ll learn how to identify any problems that occur and know when to call in the professionals at Columbia Heating and Cooling.

The most common type of HVAC system is one with central heating and cooling components. These two components work together to help keep the temperature of your home regulated and comfortable. Read on to learn more about how each of these components work to heat and cool your home.


A central heating system starts with a primary heating appliance, which in most cases is your furnace. You’ll likely find your heating appliance located in the garage or basement. Depending on your heating appliance and your region, your system will run on gas, oil or a hybrid of both types of fuel.

Furnaces contain the following critical components:

Burner: Delivers and burns fuel.

Heat Exchanger: Set of tubes or coils that act as the part of the furnace that heats the air.

Blower: Source of pressure that moves the air through the air ducts and into your home.

Flue or Exhaust: Pipe that pushes hazardous byproducts of combustion away from your home.

Your furnace works when fuel is turned into combustible gases, which are generated by the burners. These gases are passed through the heat exchanger that works to heat the air. Once the air is heated, it is pushed by the blower through a system of ducts, which is then delivered to the rooms of your home.


If you have central cooling in your home, you likely have a split system. A split system is made up of an outdoor cabinet, which sits outside of your home, and an indoor evaporator coil, which is typically installed with your furnace or primary heating appliance.

Refrigerant: Chemical that absorbs heat from the environment and transitions it from a low-pressure gas to a high-pressure liquid, and back again. The chemical produces a cooling effect while expanding or vaporizing.

Indoor Evaporator Coil: Works as a “heat exchanger” to evaporate refrigerant as it absorbs heat from indoor air that passes over it.

Compressor: The compressor pressurizes the refrigerant, turning it into a hot, high-pressure gas.

Condenser Coils: Gas leaves the compressor and flows into the condenser coils. The refrigerant releases the heat absorbed from your home. A fan blows over the condenser coils so that the refrigerant loses heat.

Your air conditioner works when warm air blows across the indoor evaporator coil. The energy from the heat transfers to the refrigerant inside the coil and is then pumped into the compressor to begin the cooling cycle. Heat absorbed from the refrigerant is pushed to the outdoor unit while cool air is blown through your air ducts.

Other Parts and Components 

Your furnace and air conditioner work together and often utilize the same components to help regulate your home’s temperature. These are some of the shared parts:

Air Return Vents. The air return vents in your home are an important part of your HVAC system. These vents draw air in and pass it through the filter. It is then passed through to the main system that either heats or cools the air.

Filter. After the air is drawn in through the air return vents, it is passed through your HVAC’s filter. This helps clean the air and filter out any dust particles or allergens. It is important to check and change your air filter at least once every 3 months.

Ducts. The air ducts in your home are the pathways that heated or cooled air travel to reach the various rooms of your home.

Need help to decide what central heating and cooling system is right for you? Your local HVAC specialists at Columbia Heating and Cooling are ready to help you find the perfect system for your home. Give us a call today to get a FREE replacement quote!