Most of us take comfort for granted when it comes to keeping our homes or businesses heated and cooled. As long as whatever system is in place works, we don’t necessarily care how the heat or air conditioning gets to us. But what if maintenance is needed? How can you tell what type of HVAC system you have?
To determine the type of HVAC system you have, look for the number and placement of installed units, the piping configuration to and from the unit(s), and whether ductwork and vents are evident. Contact a heating and air service if you’re still unsure about the type.
At some point in time and for various reasons, you may need to know what type of HVAC system you have in your home or business. In this article, we’ll discuss the types of systems and how you can tell which one you have.
Types of HVAC Systems
HVAC stands for Heating, Ventilation, and Air Conditioning and is used to describe the different ways that an indoor area is heated and cooled.
HVAC systems can be found in most buildings or inside spaces, and even in transportation systems like your car, the local bus, or subway train.
Besides moving air for temperature control, HVAC systems also filter and clean that air to maintain good indoor air quality.
HVACs help control humidity levels inside the space so that you are comfortable—not too dry, not too damp, or sweaty.
There are five main types of HVAC systems. The basic workflow of each one is the same:
- Bring in the air (from inside or outside) to the air handling unit.
- Send the air through the appropriate unit to be heated or cooled.
- Filter the air so that it’s free of allergens, dust, dirt, and other yucky stuff.
- Adjust the humidity of the air for optimal levels.
- Get the perfect air into the awaiting space.
Here’s what to look for when trying to figure out what type of HVAC system you have. We’ll go into more detail about each one later in the article.
|Characteristics of HVAC Systems||Split- Furnace/A/C||Split – Heat Pump||Hybrid Heat Pump||Ductless (Mini-split)||Packaged|
|Outdoor unit with fan and compressor||X||X||X||X|
|Two pipes from outside unit to building||X||X||X|
|Encased piping from outside unit to building||X|
|Indoor blower unit||X|
|Small air blower unit in each room||X||X|
|One unit with fan, compressor, blower||X|
Heating and Cooling Split System
The most popular type of HVAC system for residential heating and air conditioning is the split system. The split system consists of two units, one inside and one outside.
Let’s take a look at the two basic configurations you’ll find in a split system.
Furnace and Air Conditioner
With this setup, an air conditioning unit is installed outside to provide cool air inside the building on hot days. The A/C unit works in conjunction with a furnace inside to supply heat when needed.
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Usually located in an attic or under the house, most furnaces use natural gas, but some run on oil or propane. The furnace uses combustible fuel to generate warm air.
Think of it like this: the central air conditioning system uses the furnace’s forced-air system to deliver its cool air building-wide.
This split system’s closed-loop configuration circulates refrigerant, which is cooled or heated depending on the need.
Air is cooled by the refrigerant in the A/C unit or heated by a fuel source in the furnace to reach the desired temperature.
Warmed or cool air is then sent out into the ducts to blow into the interior space.
If you think you have a furnace/air conditioner design, look for an outdoor unit with a large fan plus another unit inside the building, powered by natural gas or oil and connected to ductwork.
The heat pump is a misleading term since this type of system is not used only for heating.
In fact, a heat pump is very much like an air conditioner, but when its function is reversed, it can also supply heat. One unit can efficiently provide both heat and cool as needed.
Heat pumps are most often installed in more moderate climates where the temperature stays above freezing most of the time.
The heat pump is outside, and, on the inside, you usually find an air blower instead of a furnace for moving the air into the home.
If you think you have a traditional heat pump system, your inside unit will only move air. It won’t generate heat, and you will not have a monthly bill for a fuel source.
Hybrid Heat Pump Systems
Since a heat pump can only effectively provide heat when the outside temperature is above 40 degrees Fahrenheit, a backup heat source may be used in areas where the temps routinely drop to near or below freezing.
A hybrid heat pump system uses two sources to provide heat to an interior space: the heat pump for moderately cold weather and a (usually gas) furnace for more severe cold. This system automatically switches to the furnace when temperatures dictate the need.
If you think you have a hybrid heat pump system, look for a heat pump installed outside and a furnace installed in your attic or under the house.
Ductless Mini-Split System
A ductless system is used to heat and cool specific zones within an interior space. It typically consists of a heat pump to produce cooled and heated air or, sometimes, just an air conditioner for cool only. There is no furnace option with the ductless system.
Individual air blower boxes with temperature controls are located in the rooms that need treated air. Each outside unit can run up to four air blowers, which can be installed on walls, ceilings, or floors.
If you think you have a ductless mini-split system, look for a separate unit mounted in each room. Each small box has a control panel allowing you to adjust the temperature for that space.
Packaged Heating and Air System
A packaged system means just that. All the components for heating and cooling are contained in one large unit.
The big box is usually installed outside near the foundation or on a flat roof. It has a blower to move air in and out.
Packaged systems are most often found in commercial settings on larger buildings. They can be used in a residential setting, but it’s not that common.
If you think you have a packaged system, the dead giveaway is that you only have one large unit installed outside or on the roof.
Other Heating and Cooling Systems
A few other systems are worth mentioning in our HVAC discussion. One, geothermal, is not found very often due to its initial high installation cost.
The others, baseboard and window units, and radiators are more common.
Geothermal Heat Pump System
A geothermal system functions similarly to other HVAC systems except that it uses the relatively stable ground temperature to help with the heat transfer needed to produce warm and cool air.
Pipes are buried in the ground at least 12 feet down; this is called a ground loop. Water with refrigerant runs through these pipes to facilitate the transfer of heat.
This refrigerant is circulated through a heat pump to supply the treated air to the interior space.
If you think you have a geothermal HVAC system, you’ll see that the outdoor heat pump has a pipe going from the unit into the ground and a second pipe coming out of the ground and reentering the unit.
Baseboard Heating System
Baseboard heaters use convection to draw cooler air into the unit, send it over the heating element, and then blow it into the room. They run on the standard electrical circuits already in place in a building.
A window unit is typically used for air conditioning. Installed in a window and powered by the home’s electricity, it uses one fan to blow air over an evaporator to get cool air. The second exterior fan cools off the condenser by blowing air over it.
Some newer A/C window units are also able to provide warm air for a room.
A steam radiator is a heat source only. It uses the heat from warm water or steam to heat the surrounding air. Radiators are most often made of metal since it is an excellent heat conductor.
If you’re like most people, you enjoy the modern convenience of being able to heat and cool your home without chopping wood for a fire or sitting on a block of ice to stop sweating. It’s safe to say we’re grateful for the HVAC options available to us.
HVAC may seem complicated to the average homeowner, but it really is fairly simple. With the small number of system types and a few distinct differences among them, it won’t be hard to figure out which one you have.