HVAC systems

A Detailed Guide on the Different Types of HVAC Systems

If you’re in the market for a new heating and/or cooling system, you may be overwhelmed by your choices. Fortunately, you’ll find all the help you need in the following HVAC systems buying guide.

The comprehensive list below describes all types of HVAC systems that are commonly used today. You’ll learn all about how they work and what features they provide. We’ll also tell you the ideal type of residence/climate that each system is suited for.

Furthermore, we’ll touch on the installation cost and efficiency of all these systems as well. Discover which HVAC system is right for you with this guide.

Types of Cooling Systems

There are about 8 main types of residential AC systems, each with pros and cons of their own. Here is a brief overview of their features and advantages.

Central Air Conditioners

The most common AC system for houses is the central or whole-house air conditioner. These systems include one indoor and one outdoor unit. 

The refrigerant in the indoor evaporator unit absorbs heat from the indoor air. The cooled air is blown to each room in the house through the ducts. Then, the indoor unit pumps the refrigerant, with the heat it absorbed, to the outdoor unit.

The outdoor compressor unit compresses the refrigerant to cool it back down. Then it sends the cooled refrigerant back into the house to start the cycle over again.

These are usually incorporated into one with the home’s furnace or heating system. These systems are convenient, effective, and inexpensive to install. But they aren’t quite as efficient as some of the other systems.

Window Units

Window units work the same way as central AC. However, they are comprised of only a single unit that is half inside and half outside the building, installed in a window.

These are even more common than central AC because they are the system of choice for most apartment complexes. They are usually cheaper to install than central AC since they include no ductwork.

But they are mostly only effective in very small or single-room dwellings like a studio apartment. To cool multiple rooms in a large home would require more than one window unit.

Through-the-Wall Air Conditioners

These are essentially the same as window units except they are installed into a wall of the building instead of a window. This type of unit may be installed as an alternative when there are no suitable windows in which to install a window unit.

Portable Air Conditioners

Another single-unit system that works like a window AC unit is the portable air conditioner. The main difference is that it can be picked up and moved to other rooms in the house at any time. 

These are the cheapest air conditioning solution. But they’re not quite as convenient as they sound.

Like window units, they still require a window to let out the heat they pull from the indoor air. This means you’ll have to seal the open window area around the exhaust port somehow. The process is a lot more involved than simply placing it in a room and plugging it in.

Swamp Coolers

Swamp coolers or evaporative coolers use ancient technology to cool air with water instead of refrigerant. These units pull hot indoor air through water-moistened pads that cool the air down.

These are cheap and surprisingly effective, but only in very hot and dry climates. Naturally, the water in the cooler humidifies the air while cooling it. Thus, swamp coolers are a bad choice for already humid climates.

Types of Heating Systems

Now, we’ll look at the most common heating solutions for homes. Since heating is generally a much simpler process than cooling, there are fewer types of heating systems than cooling systems.


This is the most common residential heating system. It uses electricity, heating oil, or natural gas to heat indoor air.

Then it blows the air through the ducts. If the building also uses central AC, the furnace will use the same ducts. 


Instead of circulating heated air, boilers circulate heated water. The water in boilers works a similar way (but in reverse) to the refrigerant in central AC units.

The heated water or steam is pumped to radiators throughout the house where they give off heat. This cools the water down. So, it is pumped back to the boiler where it can be heated again.

Space Heaters

These small heaters are available as portable units or permanent installations. They simply use gas or electricity to generate heat, warming the immediate area. Each of these units is only useful for heating one small room.

Combination Heating and Cooling Types of HVAC Systems

Finally, there are some HVAC systems that use a single unit to both heat and cool the building. All of these use very recent, and very efficient, technology.

Hybrid Systems

These systems are so named because they are powered by both electricity and fossil fuels using hybrid technology. This is said to make them more energy-efficient than other cooling systems.

In summer, they work like central AC to pull heat from your indoor air and blow cooled air through a network of ducts. In winter, they reverse the process, pulling heat into the home from outside.

Geothermal Systems

Geothermal systems work almost the same as hybrid systems, except they use no fossil fuels. Also, instead of pulling heat from the outside air to heat your home, they pull it from a geothermal coil installed far underground. In the same way, in summer, heat is pulled from your home and transferred to the earth surrounding the coil.

Mini-Split Systems

Lastly, ductless mini-split systems are becoming more and more popular because of how efficient they are. Rather than using one large system with a series of ducts to reach every room in the house, mini splits use multiple small systems and no ducts.

Each indoor unit works like the indoor evaporator unit of a central AC system. They pull heat from each room in the house individually and transfer it to a single outdoor compressor unit. This process is reversed to heat the home in winter. 

What makes this so efficient is that each system is only responsible for cooling one room. This requires a very small amount of energy.

Plus, if one side of the house tends to be warmer, only the units in that half of the house will run more often. Central AC would keep trying to cool the whole house simply to reach half of it. Also, the lack of ducts eliminates the possibility of duct-related energy loss.

Furthermore, each room has a separate thermostat. So, each room can be set at different temperatures. Units in empty rooms can be shut off.

However, despite their efficiency, they can be very expensive to install if you need many indoor units for your home.

Keep This Guide

If you’re currently shopping for heating and cooling solutions, don’t forget about this guide. Also, if you have a friend who is wondering about the different types of HVAC systems, please share this page.

Now, click here to learn about The Various Parts of an AC Unit and What They Do.

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