It’s easy to think of your HVAC as a single system—and in fact, HVACs are often referred to that way, even by professionals in the heating and cooling industry. However, an HVAC is made up of several different systems, each of which have specific functions. The more you know about different types of HVAC systems and how they work, the better you’ll be able to take care of your own. We’ve put together a quick guide that will help you learn the basics.
By the time you’ve finished reading this article, you’ll understand how to differentiate between the four types of HVAC systems that come together to create your heating and cooling infrastructure. You’ll also know a bit more about the main components in each system, which will help you identify problems when they occur and better understand the work your HVAC technician performs.
The Four Main Elements of HVAC Systems
An HVAC contains the following four systems, which work together to balance the climate and control the air quality in your building:
1) The Air Conditioner. Air conditioners perform two different but equally important functions. Firstly, they make the air in your building cooler when the weather outside becomes too hot to handle. Secondly, they improve the overall quality of the air inside your building, which can improve the health of occupants as well as their comfort.
Air conditioners use a chemical called refrigerant to perform their work. Refrigerant travels through several different components, which cause it to change states. As it does, it absorbs heat and moisture from the air in your building and releases it outside. The result is that the humidity and temperature in the building are both lowered, resulting in better air quality and greater comfort. Here are a few of the major parts in every central air conditioner:
- The compressor, which squeezes refrigerant and adds pressure to it while it’s in a gaseous state.
- The condenser, which allows the gas to release its stored heat to the outside air and change into liquid form.
- The expansion valve, which lowers the pressure of the now-liquid refrigerant on its way to the evaporator.
- The evaporator, which allows the liquid to absorb heat from the air around it, raising its pressure until it turns into a gas and enters the compressor again.
2) The Furnace. The furnace burns fuel to make the air in your building warmer, which can be a great comfort when the weather outside turns cold. Furnaces may use one of several different heat sources, but the most common by far in the United States burn natural gas.
The following components are essential to the way a central gas furnace functions:
- The gas valve, which supplies the fuel the furnace burns to warm the air.
- The pilot light or igniter, which lights the gas.
- The burner, which mixes the fuel with air to create a steady stream of burning fuel as the furnace is warming the air.
- The heat exchanger, through which toxic fumes and byproducts exit to the air outside your building.
3) The Ducts. Ductwork is essential for any central heating or air conditioning system, as it provides the network through which treated air travels to different rooms in the building. Maintaining the ducts in your building is one of the most important parts of keeping your furnace or air conditioner functional and energy efficient.
Ducts should be cleaned every one or two years by a licensed professional so that material does not build up inside and clog them. Clogged ducts can prevent air from moving through your building properly, which can, in turn, confuse your thermostat and cause your air conditioner or furnace to work harder than necessary. As a result, you may experience premature wear and tear or an emergency breakdown. It’s also a good idea to change the air filters in your HVAC each month so that material is less likely to enter the ducts in the first place.
4) The Thermostat. The thermostat can be considered the “brain” of your furnace. It tells the HVAC whether to use the air conditioner or the furnace to treat the air in your home until it has reached a set temperature, then turns it off when that temperature has been achieved. Some homes even have “smart” thermostats, which track the habits of a building’s inhabitants and learn to regulate their HVACs for the ideal balance of comfort and cost-effectiveness.
Four Types of HVAC Systems, Many Responsibilities
Your HVAC is a complicated apparatus, and all the systems it uses to keep your building comfortable should be properly maintained. Use what you’ve learned here to pay closer attention to your system, and to understand the work your contractor does during regular service calls or repairs. With luck, you’ll be able to keep your air conditioner, furnace, ducts and thermostat working properly for a long time to come.