How does an HVAC System Work?


Living in a climate like Vancouver, we are used to drastic changes in the temperature outside. While we can’t do much about the temperature outdoors, we have become accustomed to adjusting the temperature indoors to keep us comfortable — we can make it cool in the hot summer months and warm on those chilly fall and winter evenings.

But have you ever thought about what it is that keeps you warm or cool? Even though you make use of and are almost always surrounded by an HVAC system, you might not know that much about it. We thought we’d come up with a simple explainer on how it is the system works.

You might already know that HVAC stands for heating, ventilation and air conditioning. It’s the system in your home or office that heats the air up or cools it down while ventilating the air at the same time. Your central heating and cooling systems are two separate things, but they work through the same duct system in your home and are matched to work in tandem since they are never on at the same time.

Related Article:  What Heating System is Used to Heat Your Home?

First, let’s go over your cooling system. The most common kind is a split system made up of two parts — an outdoor cabinet unit where you can find a condenser coil and a compressor, and an indoor evaporator coil, which is usually installed in conjunction with your furnace or air handler. The compressor is an important component of the system because it pumps a chemical called refrigerant through the system which is crucial in cooling the air.

On hot summer days, the warm air blows across the indoor evaporator coil. The heat energy transfers to the coil that houses the refrigerant and it’s that transfer that cools the air. Then the refrigerant is pumped back to the compressor, starting the cycle again. Meanwhile the heat that the refrigerant has absorbed is sent outside while the cooled air is moved inside. Put simply, the air is cooled as it’s forced over the unit’s cooling coil, and then sent through the air ducts throughout your home. And voila! You are now cool and comfortable on those hot, muggy days.

When the weather turns to fall, however, you don’t exactly want cool air being manufactured and pumped inside your home, instead you want to feel warm and comfortable, which is when your central heating system comes into play.

Your central heating functions off of a primary heating appliance, like a furnace, that you’ll likely find in your basement. Furnaces are made up of four components:

  • Burners that deliver and burn fuel
  • Heat exchangers
  • Blower
  • Flue to get rid of byproducts

The type of fuel that the system utilizes depends on where you live and what it needs to function, most commonly either gas or oil, or sometimes both.

The system works when the burners create combustion gases by burning the fuel, which is then passed through a heat exchanger. When the cool air in your home is forced across the heat exchanger it becomes warm. The warm air is then blown through the system of ducts in your home (the same ones your air conditioner uses) and distributed to various rooms. Now on those chilly winter evenings when it feels like the rain will never stop, you are nice and cozy with the flick of a switch.

We hope you found this simple explainer interesting and helpful. If you have any questions about HVAC repair or installation or how it works, we are happy to help with all of your heating and cooling needs.