How Do Portable Air Conditioners Work?

Are you ready for summer? You might have big plans and have also scheduled some downtime. Summer also means heat and humidity. Are you ready for that? There are a few ways people beat the heat. Some go to the beach and cool off in the water. Others might take a cold shower. But all of us want to live in a home that has a comfortable temperature and environment.

To meet this end, homeowners use air conditioners. But there are many types! Central HVAC systems, window units, and portable air conditioners are all valid solutions. In this article, we are going to focus on portable air conditioners. Recently, we’ve been talking a bit about air conditioners here at Refrigerant HQ. Hotter temperatures will soon arrive so we want to make sure you understand your options when it comes to cooling your home. Now, let’s dig a little deeper. We’re going to explain exactly how portable air conditioners work.

Knowing how portable air conditioners work has many benefits. You will know how to fix them. You will know how to maintain them. You will even know why a certain part fails in the system and how to prevent it. Knowing how a portable air conditioner works can allow you to choose the best unit for your needs.

In this article, we’ll cover topics such as why portable air conditioners need to be vented to the outdoors. We’ll also cover the proper ways to vent the unit. Portable air conditioners let out more than cold air. They let out moisture, condensation, and heat as well. We’ll go over how to control the extra exhaust. What about the different parts of the unit? We’ll cover the major parts such as the compressor, condenser, and yes, our very favorite topic, refrigerant. Portable air conditioners can lower your monthly energy bill! We’ll explain how. And before we finish, we’ll go over some frequently asked questions regarding the inner-working of portable air conditioners.

The operation of a portable air conditioner is very detailed. But we’ll make sure to go step-by-step. Are you ready to learn more about these units?

How to Vent a Portable Air Conditioner

Portable air conditioners require venting. Before we talk about why they need venting, let’s cover how they should be vented. For now, just know that these units have an exhaust hose that needs to go out of the home.

Portable air conditioners are famous for being able to be installed quickly. And on a hot day, you’ll be happy they do! After removing the pieces (there aren’t many) from the box you’ll put it together. The exhaust hose is one of the few major removal pieces. You already know that the hose needs to be connected to the outside of the home. Therefore, first, you need to decide what room you want to cool. Does the room have a window? If so, you found the perfect place to set up your portable air conditioner.

The unit comes with a venting window kit adapter. It is normally a rectangular-shaped piece of plastic that screws onto the exhaust hose end. This adapter is meant to fit securely in a sliding window. Your window may slide vertically or horizontally. It doesn’t matter which way your window slides as long as you can fit the window kit adapter in place. Here’s the good news: the window kit adapter is adjustable. Some adapters slide to become wider or shorter. Others are able to be cut to make them fit in the window. Once you find the right size, it’s time to secure it in the window sill.

The exhaust hose should be as straight as possible. It should not be tangled. This is so the exhaust from your portable air conditioner is able to move outside without being impeded in any way. If the exhaust hose is impeded or doesn’t work properly, the exhaust from the unit could stay in your home.

One last note is that the exhaust hose should not be lengthened in any way. The portable air conditioner may only be able to push the exhaust a certain distance. And that distance is probably not much longer than the exhaust hose. I understand that you might be to position your portable air conditioner in a certain part of your room. However, the unit must stay close to the window for it to work properly.

Why Portable Air Conditioners Needs Venting

To know this, you have to know how these units work. The easiest way to explain this (and we’ll get more detailed later) is that the portable air conditioner simultaneously removes warm air from the home (via the exhaust hose) and cycles cool air back into the room. This is the real reason these units come with an exhaust hose. If they didn’t, the warm air would simply stay in the room! It wouldn’t make much sense, then, to use one of these units without a way to get the warm air out of the home. Remember folks, that air conditioning isn’t about creating cold air but about removing the heat from the room.

The portable air conditioner releases more than just warm air. Moisture and condensation are also emitted from the machine. These are just two more reasons why an exhaust hose is needed. Excessive moisture and humidity can cause mold which brings another host of problems. Let’s take a closer look at how moisture and condensation play a role with the portable air conditioner.

Moisture, Condensation, and Draining

Portable air conditioners pull moisture out of the air in a room. They do this along with pulling out warm air. The moisture isn’t always exhausted through the hose and out of the home. Instead, many portable air conditioners come with a removable condensation or drip tray. Every so often, the tray should be removed and the liquid condensate can be poured down a drain. If the tray isn’t removed it will overflow. However, many units will notify you if the tray fills up too much.

Some of the higher end portable air conditioners do not have a drip tray that needs to be emptied often. These units have a condensation exhaust system which typically takes care of any moisture and condensation. They way it works is simple. The units remove water vapor which is collected during the dehumidifying and cooling process. These portable air conditioners are called auto evaporation units. An example of a higher end unit that does this is the Honeywell MN10CESBB.

Whynter 14,000 BTU Dual Hose Portable Air Conditioner
Whynter 14,000 BTU Dual Hose Portable Air Conditioner

The Honeywell MN10CESBB is a unit with 5,500 BTU which will cool a room up to 450 square feet. This unit is perfect for bedrooms or rooms with a similar size. 80.1 pints of moisture are removed every 24 hours. If you want a portable air conditioner that runs by itself and requires almost no maintenance, the Honeywell MN10CESBB is the perfect choice for you.

Another option is the Honeywell HL14CHCS. This unit has 8,500 BTU which is enough energy to cool a room up to 700 square feet. An added bonus with this unit is that it doubles as a heater. You might live in an area with hot summer and cold winters. If so, this unit might be the perfect choice for you. This unit removes 111 pints of moisture every 24 hours.

What type of portable air conditioner do you prefer? Removing the tray is incredibly easy to do. On the other hand, some people prefer the auto evaporating units with almost no maintenance. The price difference between the higher end models and the standard ones is minimal. For a higher end unit, you can expect to pay another $100 or so. It’s also important to consider the additional features that higher end units have. Those might be worth the extra hundred or two hundred dollars.

How it Works

You know that you should vent a portable air conditioner. And you now know the proper way to vent it. You even know that these units emit moisture and condensation. Now, it’s time to take a closer look at the major moving pieces in this machine. How does it work? There’s a lot under the hood. Let’s get started.

First, you should know of the major components in a portable air conditioner. These include a compressor, condenser, refrigerant, condenser coils, evaporator coils, and blower. Each of these components has a job to do. Without any of them, the portable air conditioner would not work. Let’s start with refrigeration. After all, it’s our favorite topic!

Portable air conditioners work by removing humidity in the air. This helps to cool the room. Refrigerants play a key role in this process. The refrigerant is a gas or liquid depending on the state which can quickly move from a low pressure to a high pressure situation. It can also quickly change from a gas to a liquid and back to gas form. When the refrigerant cycles through the system it’s a cool, low pressure gas. The refrigerant first goes through the compressor.

The compressor quickly pressurizes the refrigerant. In doing this, the compressor converts the cool refrigerant into a heated gas. When the refrigerant is pressurized, it squeezes the molecules of the gas together. This helps to create the higher temperature of the gas. The closer molecules come together means the higher pressure the gas will become. Next, the gas will travel through condenser coils.

It’s time for the gas to be cooled down again. And that’s the job of the condenser coils. It’s also time for the gas to become a liquid! When the gas cools down it dissipates and become a liquid. This happens because the volume of the gas expands. It’s important to note here that the gas-turned-liquid still retains its high pressure. Before the gas moves on, it has to pass through a small, narrow opening. The high pressure of the liquid helps it push through this small opening. Next, it’s time for the liquid to lose some pressure. And that’s the job of the evaporator coils.

The evaporator coils quickly depressurize the liquid. In doing so, the liquid becomes a gas again. The condenser coils in the last step cooled down the gas. With the liquid going through the evaporator coils and becoming a gas, the gas cools even more. The evaporate coils are the last component the gas goes through before exiting the portable air conditioner.

When the cold air exits the portable air conditioner it mixed with the warm air in the room. Air, whether warm or cool, continuously cycles through the portable air conditioner. It does this even when the room is cold. Any excess moisture and condensation should go through the exhaust hose and to the outdoors. Remember, some units have a condensation tray. However, higher-end models are better at removing most moisture and condensation from the home.

How Portable Air Conditioners Lower Your Energy Bill

Knowing about the money you can save it just as important as knowing how a portable air conditioner works. Well, you’re in luck because we can talk about that too!
One of my favorite things about portable air conditioners is how efficient they are. What I mean is that they can cool a room within minutes. With a central HVAC system, it usually takes a bit longer to cool the room. That’s because the HVAC system is working to cool the entire home along with the room you want.

Even if you have an HVAC system, a portable air conditioner can save you money. Let’s say that you spend most of your time in one room in your home. Instead of running the HVAC system all day, you can run the portable air conditioner. By doing this, you will save energy you’d instead be using to cool the other rooms you aren’t using.

When HVAC systems get older they don’t work as well as they did when they were new. Older HVAC systems could take longer to cool a home which uses more energy. The more energy you use during the month the more expensive your monthly energy bill will be. Instead of replacing your HVAC system, which could cost thousands of dollars, you could buy a portable air conditioner for only a few hundred dollars. The unit isn’t necessarily meant to replace your HVAC system. However, it could be a great solution to supplement your central air system. These units are also a great solution to cool a garage, loft, or out building for your property. I personally use one of these for my workshop that’s a few hundred feet away from my home. I’ve got power routed out and a window. That’s all I need!

Portable air conditioners are easy to move around the home. They do require minimal installation when it comes to venting out a window. Some people choose to buy two units instead of one for convenience. Multiple units are also a good option for those who have limited mobility.

Frequently Asked Questions

If you’re considering buying a portable air conditioner you probably have a few questions. We’ve listed a few of them below to help you with your consideration. If you have additional questions feel free to contact us. We can help you choose the perfect portable air conditioner for your needs.

• Which portable air conditioner is good for a bedroom?

To answer this question you should know the square footage of your room. Portable air conditioners are sorted by BTU. For example, a bedroom should have around 7,000 BTU. You might want to read our article What Are The Best Portable Air Conditioners?. We’ve listed our favorite portable air conditioner choices for different rooms sizes based on BTU level.

EdgeStar AP12000S Portable Air Conditioner
EdgeStar AP12000S Portable Air Conditioner

• Should I choose a portable or window air conditioner?

Portable and window air conditioners are similar. They both cool a room have similar price points. Depending on cost, they might include a multitude of features. Portable air conditioners are more versatile than window units, which move sits tightly in place. To compare the differences between the two in greater detail you should read What Are The Differences Between Portable And Window Air Conditioners?.

• What is required to install a portable air conditioner?

Each portable air conditioner is different. That being said, you’ll need a window or other place to install your exhaust hose to the outdoors. Most portable air conditioners don’t require any additional tools. You may be required to cut a window kit adapter to make the hose fit perfectly in place. But many units also have adjustable window kit adapters. Before buying a unit, make sure you research the requirements of the unit and if any additional tools are required.

• Will the portable air conditioner cool multiple rooms?

This question can be answered if you know the total square footage of the rooms. The most important factors are the following: the square footage of the rooms, the BTU level of the portable air conditioner, how close the rooms are to each other, and where the unit is placed. A 7,000 BTU unit will cool a bedroom which is between two-hundred and fifty to three-hundred and fifty square feet. For two bedrooms of the same size, you’ll need to double the BTU level to 14,000. You must also take into consideration the placement of the portable air conditioner and any obstructions such as a wall. The best place for the unit to be would be in the middle of both entrances to the room. Otherwise, choosing a more powerful portable air conditioner should do the trick.


Let’s put it all together now. Knowing how a portable air conditioner work can help you appreciate what it can do for you. And here’s the most important part: it will cool your room!

It’s not hot and humid outside yet. But it will be. Will you be ready for the days when the temperature will be over one hundred degrees? Consider your HVAC system, if you have one. Depending on its age and how effective it is you may also want to consider buying a portable air conditioner.

The area you live in is also important. If you live in a warmer area closer to the equator you’ll probably only need a portable air conditioner. However, if you live in an area that has hot summers and cold winters you might want a portable air conditioner and a  portable space heater. The good news is this: you can buy units that have both features combined! This will save you money and space in the room you want to cool and heat. You can even leave the unit in the room all year since you’ll use it during opposing seasons. Our preferred pick is Black and Decker’s BPACT14HWT.
As it gets warmer we’ll make sure to write more about air conditioners and how they will benefit you most. I hope you enjoyed the article. Check back soon for more!