How Do Portable Air Conditioners work?

The working mechanisms of a portable air conditioner are very similar to that of a refrigerator. The only difference between your fridge and portable AC, therefore, is just that the fridge cools its inside while the AC cools the outside as well. 

A portable air conditioner works by pulling in hot air, cooling it and then blowing it back into the room. Some air conditioners have the option of condensing the water vapor in the air thus effectively dehumidifying the room. 

How Do Portable Air Conditioners Work?

The main parts of a portable air conditioner are the:

• Fan – moves the air into and out of the AC
• Refrigerant – cools the hot air
• Compressor – compresses the refrigerant

These three parts work together in the following steps:

1. The spinning motions of the fan draw hot and humid air from the room into the air conditioner. 
2. The hot and humid air is cooled by the condenser coils. These coils have a cold refrigerant inside them and are made of a thin metal which allows for the transfer of heat between the refrigerant and the air around them. 
3. The cooling of the air also condenses the moisture in it into water. This water can then be eliminated either by the AC itself or collected and manually removed. 
4. The cold and less humid air is then blown back into the room. 
5. With time, the hot air heats up the refrigerant in the condenser coils into a gas. This relatively hot gas is compressed back into a cold liquid ready to cool the hot air from the room again. The heat generated by the compressor when cooling the air is then vented from the air conditioner with any hot air that isn’t cooled after going over the condenser coils. 

This process is repeated over and over again with on-device settings being used to vary various parts of it such as increasing the speed of the cooling, dehumidification and others. The procedure is the same no matter the type of air conditioner but portable AC units have all these parts and processes in one single unit. 

Types of portable air conditioners

Portable air conditioners are categorized based on how they vent the hot air and moisture, how they cool or warm the indoor air among other aspects. The main types are as follows:

1. Number of hoses

Based on the number of hoses the AC has, the categories are as follows:

a. Single hose portable air conditioner

Single hose portable AC units work by drawing in hot and humid air then send out the excessive hot air and water vapor through a single hose. The problem with this setup is that it creates negative pressure indoors since it’s drawing air from the room but not replacing it with air from outside to fill the void created. 

Single hose portable air conditioners are effective in small rooms where the pressure difference won’t be easily noticed. They are also cheaper than dual hose portable air conditioners. 

To have the best service from a single hose portable AC, limit its access to hot air from other rooms or areas by closing the door when its in use.

b. Dual hose portable air conditioner

Dual hose air conditioners have two hoses with one drawing in air into the air conditioners and the other one acting as the exhaust hose. This setup eliminates the issue of negative pressure in the room since the air drawn into the AC is equal to the air vented out. 

Dual hose portable air conditioners are thus suited to larger rooms. They are more energy efficient and provide quicker cooling than single hose AC units. They are, however, costlier than the single hose air conditioners

2. Drainage categories

Do you have to drain water from a portable air conditioner? Yes and No as it all depends on the type of portable air conditioner you have. The condensed water needs to be eliminated from the air conditioner regardless of the type of air conditioner. There are different portable air conditioners with different ways of doing so as follows:

a. Self evaporating portable air conditioner

For this model, you don’t need to drain or empty the condensed water. Instead, the air conditioner evaporates then vents out the steam with the rest of the hot air from the work of the compressor. It means you simply have to turn it on and you’re good to go as it needs very little maintenance. ACs made by Avallon, Whynter and DeLonghi have this feature. 

b. Gravity drain with or with no condensate pump

The gravity drain type of portable air conditioner eliminates the condensed water through a drain hose attached to it. The water moves downwards through gravity hence the name. You can then direct the drain hose to a drainage system or other location as you see fit. 

The second type of gravity drain system has a condensate pump that pumps the condensed water into another location such as your sink. This works best when you don’t have a drain near the location of the air conditioner.

See also: Why Your Portable AC Fills Up with Water Too Fast

c. Collection bucket (tank)

The last type has a tank or bucket in which the condensed water collects. After a while, you have to turn off the air conditioner then empty the tank before it overflows. 

3. Ventless portable air conditioner

Often called the ventless air cooler, ventless portable air conditioners are equipped with a water tank or reservoir. The water in this tank is evaporated to cool the house down. The tank also collects the water collected as the AC cools the air. 

4. Windowless portable air conditioner

A windowless portable air conditioner doesn’t need to be placed close to a windowsill as they can be connected to the window through a single hose system and still work effectively. These air conditioners can also be used to remove odors from a house although they take quite long to work and cool large rooms. They work quite well in combination with central air conditioners. Their main advantage is their ease of installation. 

5. Portable reverse cycle air conditioner

This type of air conditioner can be switched to draw air from outside to warm the inside of the house instead of cooling it. This means that the portable reverse cycle conditioner can be used to cool and warm the house at different times with a switch. This feature saves on the cost of buying an independent heater. 

How to install portable air conditioner

A portable air conditioner is easy to set up and use since you primarily need to have these three:

• An opening to the outdoors such as a window, door or ventilation hole. 
• Space near the opening to the outdoors. 
• A power outlet near the location of the air condition. An 115/120 Volt outlet is enough for AC units with less than 14,000 BTUs capacity. For those above this rating, you may need an independent circuit to avoid power overloads. 

To install a portable air conditioner, follow the steps below:

1. Choose the right location

This should be close to the window where you can you can easily install the exhaust vent to point outdoors. 

2. Connect the exhaust hose to the AC unit and the window

The exhaust hose should be on the back of the air conditioner with the other end connected to and exhausting away from the house to the outdoors. 

3. Connect the power cable to the power outlet

Make sure the power outlet has the right rating to avoid overloading the circuit. 

4. Turn on and adjust the air conditioner accordingly

With everything in place, turn on the air conditioner then change the settings to what you want depending on the weather and time of day. 

How to vent a portable air conditioner without a window

Most portable air conditioners will require being vented through a window with the exhaust hose being pointed outside the house. The hose is usually between 4 and 7 feet long which is long enough for most setups.

This, however, isn’t the only way to vent a portable air conditioner since you can also use a sliding door for the same purpose. Given that most window kits aren’t long enough to fit the entire height of a sliding door, you will need the following:

• An extension kit for the air conditioner vent
• Plywood or Styrofoam to fill any empty void created

One of the most commonly asked questions about this aspect is “can you extend the exhaust hose on a portable air conditioner?” The answer is yes, you can extend the exhaust hose on a portable air conditioner although only to the extent allowed by the manufacturer. Beyond the recommended length, the machine won’t be operating efficiently and it might overheat and void the warranty from the manufacturer. 

Other methods of venting a portable air conditioner include through:

• A hole in the wall
• A chimney
• A drop ceiling

As long as the hot air can be eliminated from the room, the AC unit will work fine. 

What size air conditioner do I need?

If you’re wondering what size of an air conditioner you need, the guideline is as follows:

• Small rooms: for rooms up to 300 square feet, you should get an AC between 7,000 and 10,000 BTUs. 
• Medium-sized rooms: rooms between 350 and 700 square feet large will require between 11,000 and 14,000 BTUs for the AC. 
• Large and commercial rooms: commercial applications will have different sizes depending on the type of building it is. Large rooms will have AC unit rated 14,000 BTUs or more in general. 

This sizing guide works for offices and homes alike. 

Common features for portable air conditioners

Some of the most common features on portable air conditioners include:

• Dehumidify/Dry Mode: the AC extracts moisture from the indoor air but doesn’t cool it down. 
• Timer: you can set the start or stop time for the AC unit with this feature. 
• Oscillation: the AC unit will rotate its air vents side to side to cool the room evenly. 
• Auto Mode: this setting keeps the temperature of the room within the set range by turning the AC on or off or changing other settings. 
• Fan Mode: this setting only circulates the air in the room without changing its temperature. 
• Remote: with a remote control, you can control the AC from afar. 

Not all AC units will have all these features though. 

How make a portable air conditioner work better 

The best maintenance for portable air conditioners includes the following aspects:

• Keep the condenser coils clean. When they get dirty, the rate of heat transfer between the air and the refrigerant is significantly reduced. This also reduces at the rate at which air is cooled in the house. 
• Clean the air vent grill by wiping it down with a piece of cloth. This prevents air blockages in the vent. 
• When using a portable AC unit that has a collection bucket or a ventless AC, you need to empty the bucket/tray at least once a week and wash the tray each time you empty it. This prevents the growth of mold on the tray and inside the AC unit. 
• The air filter for the AC unit should be cleaned every fortnight (2 weeks) to prevent clogging which will reduce the effectiveness of the air conditioner. Only put it back into the AC unit after it has fully air dried. 
• Clean the outside of the air conditioner every one or two months. When cleaning the exterior, unplug it then use a wet cloth that is lint-free. Use a mild soap or detergent for this purpose and make sure water doesn’t go inside the AC unit. 
• If you won’t be using the AC unit for a while, store it in its original package or cover it with a piece of cloth then store it on a raised platform. 
• Place the unit in the room correctly which is close to a window for the best experience. 

These tips will keep your portable air conditioner in good working conditioner and for longer. If you live in a dusty area or have pets and lots of lint in the home, these exercises should be done more often. 

FAQs

• Can a portable AC unit cool more than one room?

A portable AC unit can be used to cool more than one room if the AC is large enough and the two rooms are connected. 

• Do portable air conditioners work without a window?

Portable air conditioners can work without a window although you will still need to provide a way to vent the hot air outdoors. You can use a door, drop ceiling, hole in the wall or chimney to vent the AC. 

• Do all portable air conditioners have to be vented out a window?

All portable air conditioners have to be vented outside although they can use a window or other vent. 

• Do you have to put water in a portable air conditioner?

Most portable air conditioners don’t need water to be put in them to work. However, ventless air conditioners need a tank of water in them to work. 

• Are portable AC units any good?

Portable air conditioners can cool a room quite well although the heavy units aren’t so efficient. While portable AC units are better than simple fans, they’re not as effective and efficient as window AC units. 

• How loud are portable air conditioners?

Most portable air conditioners will produce between 40 and 60 decibels of noise. That is a bearable range for most people. 

Tim David

HVAC tech with over 30 years of experience. Retired and doing repair work on the side around Madison County, AL.