What Are The Types of Air Conditioners?

What are the types of air conditioners available? A question many people ask when buying an air conditioner for the first time.

I remember the first air conditioner that I bought back in 2015 when I moved to Dallas, one of the hottest places in the country (source). I was new to such high heat; back home in Minnesota, the highest temperature we ever got was about 50°F!

But when I got down to buying an AC, I was baffled by the vast array of possibilities. The sales guy ran hoops around me, and I was about to buy something expensive. Luckily, I had the good sense to walk out of there before I committed to anything.

I spent the next couple of days researching online and talking to friends. I learned a lot, but it took a while; there was no single overview to explain all the details and differences. Therefore I thought, why not put together a definitive guide to answer your questions?

The Types of Air Conditioners

I have classified ACs into 8 broad segments, based on their usage, external features, size, and technology. Let us explore each.

1. Central Air Conditioning

Central AC is perhaps the most common and popular form of air conditioning, especially in large homes. It is a very efficient way of cooling many rooms and spaces simultaneously.

Central AC works in a somewhat different way than other air conditioners. A cooling compressor, usually placed outside the house, is responsible for the cooling process. 

The air is cooled in the same way as other AC configurations: through the use of a refrigerant-based coil. However, once the air is cooled, the AC sends it into the house using a duct system that runs through every room.

Warm air is carried back to the cooling unit through the same ducts and gets pushed out through an exhaust. Central ACs can use the same old system of ducts that runs through most houses to heat from a central furnace.

Advantages

• Adjust the entire homes’ temperature through a single system.
• Central ACs can provide cleaner and less humid air
• Central air conditioning is much quieter than portable or window ACs

Disadvantages

• Central ACs can be inefficient. If you need to use only one room more often than others, a central AC will end up making you spend for cooling the entire home, whereas it would be much more efficient to put in just one window or split AC.
• Centralized AC may cost anywhere between $5,000 to $15,000, depending on the size of the house.
• Ductwork can be costly if you have to put it in from scratch
• The ducts require much more intensive and regular maintenance than most other forms of air conditioning.

Related article: What Temperature Should I Set My Air Conditioner

2. Window Air Conditioners

Perhaps the most common type of air conditioner is the ubiquitous window ACs that you can see in many places in Texas. Window air conditioners work on two cycles: room air and hot air. 

Room Air Cycle

The AC uses a special liquid called refrigerant. The air conditioner turns the refrigerant first into a gas and then back into a liquid. In the process, the refrigerant cools down. This liquid refrigerant passes through a system of evaporator coils inside the AC.

The ACs blower sucks in hot air from your room and passes it over the cold refrigerant coils, causing the hot air to cool down (and lose its humidity as well, since the water content condensates on the coils carrying the refrigerant). This cold air is then pushed back into the room, making the room cooler and less humid.

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Hot Air Cycle

The hot air cycle is the other side of the coin. The refrigerant in the previous cycle sucked the heat from the room air but became hot, turning into a vapor form. It needs to be cooled down again to reuse it.

Firstly, the compressor of the AC converts the vapor refrigerant back into liquid form. The compressor then sends this liquified refrigerant to the condenser unit at the back, exposed to the external atmosphere (the part hanging out of the window). It consists of condenser coils and another blower.

When the refrigerant passes through condenser coils, it cools down due to the air from the atmosphere outside, losing its heat to the air outside. Which blows out from the back (if you ever stood behind a window AC, you know what I am talking about).

The AC further cools down the refrigerant through a process known as throttling, and then the whole cycle is repeated.

Advantages

• Window ACs are usually quite cheap. You can easily get a 12,000 BTU window AC for under $400
• Most window ACs are much more energy-efficient than comparable split ACs or other options. 
• They do not take up space in your room, unlike portable ACs and evaporative coolers.
• You can reinstall them from one room to the other, unlike Wall ACs. You can even remove them in the winter months if you want access to your window.
• Window ACs are good for supplemental cooling, where you avoid using a central AC (which cools the entire home) and instead cool the room where you are currently sitting. This localization saves you a lot of money on your electricity bill.
• Window AC maintenance is quite simple. You have to clean the air filter and the coils, and that’s about it. Most compressors will work well for 5-10 years.

Related articles:
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Disadvantages

• Window ACs can only cool one room, so they are not a great solution if you have a large home.
• You will lose one window and thus the sunlight and airflow.
• While they are energy efficient, their cooling power is usually limited. The best you can hope is to cool one room at a time.
• A less commonly understood disadvantage is that they are an easy way for burglars to enter your home, particularly if you place the unit near the ground floor.
• Window ACs can be noisy. If you are a light sleeper, you should think twice about getting a window AC installed.
• They leave a trail of water dripping down, and depending on the location, your neighbors will be affected by this dripping water. You can usually rectify this by putting in something to collect the water or attaching a drain pipe that runs down to the ground.

3. Ductless Mini Split AC

Ductless mini-split ACs, as the name suggests, split the conventional air conditioner into two parts: an indoor unit and an outdoor unit.

As I had explained earlier, an AC works in two cycles: the room air cycle (evaporative process) and the hot air cycle (condensation process). The concept of a split AC is to separate these two processes in different places. The condensation process and the compressor involved in it are noisy. Having that part outside your room or in a separate location connected by insulated lines significantly reduces noise in the room.

Operating a split AC may cost anywhere between $4,000 to $10,000, depending on the tonnage and the installation size.

Advantages

• As mentioned above, split ACs are very quiet.
• A single large outdoor unit can control multiple indoor units, thereby effectively replacing the ductwork needed for a central AC configuration. 
• You can control each indoor unit’s temperature and operation separately.
• Compared to central air conditioning, split ACs can be a cost-effective alternative in the way described above.

Disadvantages

• If you already have ductwork in your place, split ACs will be a costly proposition when compared to central ACs,
• The tubing between the indoor and outdoor units limits where and in how many rooms you can install the AC. Beyond 50 feet, the refrigerant that needs to run between the two units may have too large a change of temperature.
• Installing split ACs requires a bit of modification to the building, which may not be possible in managed residences.
• It is best to get split ACs installed by an expert since you might end up voiding manufacturer warranties if you install them independently.

4. Wall Air Conditioners

Through-the-wall air conditioners use the same technology as Window ACs, but instead of venting out air from all sides, they only expose the back of the AC to the outer atmosphere.

Wall AC Installation

Installing a wall AC requires planning and approvals (especially if you’re not the homeowner). They are permanent fixtures. 

You need to cut a hole in a wall that faces the exterior of the house. You then install a sleeve inside this hole, which can support the weight of the AC (the wall may not be strong enough to carry this weight). 

Advantages

• You don’t lose the usage of your window. Secondly, if your room does not have a window, then a Wall AC may be the best option for cooling the room.
• Since you create an airtight seal around the wall AC, your room is secure for the winters, and the AC works more efficiently.
• They are usually quieter than Window ACs.

Disadvantages

• It is a permanent fixture, so there is no portability at all. You will probably need permission to install such a fixture in your room.
• Installation requires expertise, and professional expertise always costs money.

5. Portable Air Conditioners

Portable air conditioners are another example of a standalone unit with all its components in one place, unlike split ACs or Central ACs. They usually have casters attached for easily moving them around. Portable ACs cool either a single room or a smaller area.

They use almost the same technology as window ACs for cooling, using a cooled refrigerant to cool down room air and expelling hot air generated in the process through a vent in a nearby window. They usually have a small drain tank that collects moisture from the dehumidified air.

Portable ACs come in two varieties: single and dual hose.

Single Hose

A single-hose portable AC pulls warm air from inside the room, cooling it down and then expelling excess warm air outside using a hose and vent system. Single hose systems use up less electricity than dual hose ones.

Dual Hose

The dual hose, as the name suggests, uses two hoses. One hose is pulling in fresh air from outside the room, which the AC cools down and circulates inside the room.

The other hose takes excess heat and humidity from the room and sends it outside using the exhaust hose and vent.

Dual hose systems are usually more robust; they cool better and more quickly than a single hose.

Advantages

• Portability is the most crucial advantage of these ACs. You can install and reinstall these ACs anywhere you like in the home. It takes minimal effort and time.
• They are pretty inexpensive. Most portable ACs will cost you less than $500, assuming you are looking for something under 12,000 BTU.
• In buildings where the building management disallows modification to the home, portable ACs are the best solution.
• Portable ACs are cost-effective. If you have a small apartment room (<500 square feet), the cheapest combination is to get a room heater and a portable AC for all-year comfort. Some portable ACs come with a heating unit also built-in, which can be a great option.
• They are energy efficient. For cooling a small-sized room, you need not spend a lot of money running a central AC.

Related articles:
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Disadvantages

• Portable ACs are limited in their ability to cool. Due to their small size and the need for portability, these machines cannot cool a large area.
• Just like window ACs, these machines can be a bit noisy.
• You have to keep draining out the water from the collector tray in most portable ACs.

Related article:
5 Quietest Portable Air Conditioners

6. Evaporative Coolers or Swamp Coolers (aka Ventless AC)

Evaporative coolers or swamp coolers (also known as ventless portable air conditioners) have a long and colorful history. They work on a very ancient principle that the earliest civilizations in the world have also used.

Evaporative coolers use the natural process of evaporation for cooling. They pull in hot, dry air from outside, pass it through a moistened pad that absorbs the heat from the air, cooling and humidifying it by as much as 20 degrees. 

They then recirculate this cool air back into your room, creating a gentle but somewhat moist breeze. You may feel it as something similar to sitting near a beach or a waterfall. 

Where Should You Use a Swamp Or Evaporative Cooler?

Evaporative coolers work best in hot and dry climates like the southwest states. They add moisture to the air, which can feel damp if you live in a humid state.

Advantages

• Since the process is natural, evaporative coolers are energy efficient. They use nearly ten times less energy than other ACs and cost much less.
• Unlike portable ACs, there’s no installation or venting needed. Just add water to the tank, and you’re good.
• Air conditioners use refrigerants for cooling, which is depleting our ozone layer. Swamp coolers are completely eco-friendly since all they use is water.

Disadvantages

• They don’t work well in hot and humid climates.
• It’s important to keep a door or window open to create a fresh air supply when running the cooler inside. Otherwise, it will circulate humidified air in the room.
• You have to replace the water in the evaporative cooler regularly. 
• If you are using it outdoors, there is a chance of bugs and mosquitos accumulating in the water, so it’s important to keep cleaning out the water tank.
• It would be best if you also kept changing the pads almost every two or three seasons.

7. Package Terminal Air Conditioners (PTAC)

If you have stayed in many hotels, you might have sometimes noticed a package of air conditioners installed between a window and the flooring of a room. This device is known as a PTAC.

Apart from hotels, you can find PTAC’s in many places such as assisted living facilities, hospitals, and other commercial establishments.

Much like wall ACs, PTACs have a part facing the outside of the wall. However, they are entirely self-contained and do not drain out water because they have a condenser fan that converts condensed water into water vapor again through external heat. 

PTACs are a convenient option for commercial establishments where central air conditioning is not an option. You can also use them in residential settings.

Advantages

• PTACs are much more energy-efficient than HVACs, especially for smaller establishments.
• They do not need any ductwork, significantly reducing costs.
• They save a lot of space because they are installed entirely in the wall, do they not occupy your window.
• Most PTACs have both heating as well as cooling in a single unit.
• If you have a room that has a lot of sunlight, wasting the central ACs power to lower the temperature of one room is not energy efficient. Instead, you can cut off the central AC and install a PTAC in the room.
• Since they are not centrally controlled, hotel room guests can choose their temperature.

Disadvantages

• If you were to consider using PTACs for every room, you would find that doing it in more than 2 or 3 rooms will quickly become more expensive than central AC.
• PTACs can be louder than regular split AC.

8. Geothermal Heating and Cooling

Geothermal cooling is a revolutionary, zero-emission, zero-ecological-harm technology for both heating and cooling your home. If you think geothermal heating is an obscure thing, consider this: more than 50,000 new homes use geothermal systems every year. 

The basic principle of geothermal heating and cooling is this: the ground below the earth’s surface (about four to six feet below) maintains a temperature between the range of 45 to 75°F. Its temperature is always less extreme than the temperature on the surface.

A looped polyethylene pipe runs from your home to a place underground that circulates water between the house and a heating pump. 

During the winters, the water absorbs heat and gets warm. This water is then heated further by compression and is used to heat the home.

During summers, the device uses a reverse process. The heated water from your home comes to the ground, loses its heat, and cools, and then cool air circulates in your home.

Advantages

• The most important advantage is, of course, eco-friendliness. You do not need to burn fossil fuels to produce electricity for heating or cooling. Neither are CFC chemicals released during the process.
• The same system can both heat and cool your home.
• Compared to other renewable sources of energy such as wind and solar, geothermal energy is more reliable. 

Disadvantages

• Currently, this method of cooling is very expensive. It can cost anywhere between $30,000 to $50,000 to install in a large-sized home.
• During the process of digging, some greenhouse gases inside the earth’s surface get released.

Types of Air Conditioners: Wrap Up

Bringing this information piece to a close, I hope that I have answered your questions regarding the types of air conditioners and which ones will be fruitful for your specific needs and situation. 

If you have more questions, please drop in a comment below, and I will try to get back to you as soon as possible!

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