Use A Portable Air Conditioner As A Dehumidifier – A Complete Guide

Living in a humid environment will pose numerous health risks to you, making a dehumidifier a must-have for many households.

Many electronic devices nowadays are multifunction, so people always wonder if they can use one as an alternative to another. For example, many friends have asked me if they can use a portable air conditioner as a dehumidifier. 

While portable air conditioners can help dehumidify the air, they are not as effective as dehumidifiers at removing moisture.

I will explain the dehumidifying function of different types of portable AC and guide you on when you should use a portable AC or dehumidifier. 

Why can a portable aC be used as a dehumidifier?

As I just mentioned, you can use a portable ac as a dehumidifier. In this section, I’ll explain why this is possible.

To begin, you should have a fundamental understanding of how these two devices function.

How does a portable ac work?

The portable ac looks like a bigger portable dehumidifier but can not only dehumidify the air but also cool the room down. The air is drawn into the machine by a fan and then passes through the evaporator coils, which are very cold. 

This causes the air temperature to fall, and when the temperature reaches the dew point, the air becomes saturated, and the water vapor in the air condenses into liquid.

After finishing this process, the cooled air will get into the room, and the water will be collected in the tray and expelled outside. 

How does a dehumidifier work?

The air gets into the dehumidifier with the help of a fan. When air enters the machine, it comes into contact with the evaporator coils, where condensation forms and the atmosphere is dehumidified.

Then it will go through another coil – condenser coil, which can heat the air, ensuring the air is at room temperature when it returns to the room.

The working principles of dehumidifiers and portable air conditioners are similar in that both use an evaporator to cool the air and remove moisture through condensation.

Therefore, you can use a portable AC as a dehumidifier because it is able to get rid of some moisture in the air. However, because it is not designed for that purpose, it is not as effective at removing moisture as a dehumidifier.

How is a portable AC with a “dehumidifier mode” work?

If you look at the control board, you may find an operation mode called “dry mode” or “dehumidifier.”

This is a mode the manufacturer provides for you to dehumidify the air specifically. That is to say, this portable AC has a built-in dehumidifier. 

The fan and compressor will slow down in this mode, giving the air more time to interact with the cold evaporator coils. As a result, more water vapor will condense, resulting in a lower humidity level in your room.

When this mode is on, you can see more water get out from the drain hose.

How to improve the efficiency of dehumidifying in a portable AC?

Whether your dehumidifier has a “dry mode” or not, there are some ways to make it more like a dehumidifier. 

Use an appropriate-sized portable AC in the room

Sometimes, the room is still very humid when the AC is on and the most common cause of this is the product’s size.

A portable requires 20 BTUs per square foot on average. While a small unit may be unable to cool the room and reduce humidity, an oversized unit will cool the room so quickly that the machine does not have time to dehumidify all of the air in the room.

As a result, to ensure your portable AC can dehumidify the room effectively, you should place your portable AC in a room of the proper size.

Leave the vent hose in the room

improve the dehumidifying efficiency of portable ac

The relative humidity level will rise when the room temperature falls. Since the portable air conditioner will lower the temperature, the moisture level may not change significantly. 

You don’t want to cool the room in the winter. In this case, leave the vent hose in the room so that the warm air offsets the cool air to some extent, allowing your portable AC to dehumidify the room without overcooling it.

This method is not applicable for an evaporative portable AC as the venting hose is also responsible for expelling the moisture.

Should you use a portable air conditioner or dehumidifier?

Again, the primary function of a portable air conditioner is to cool the room, whereas the primary function of a dehumidifier is to remove excess moisture from the air.

If you live in a dry but hot climate, a portable air conditioner is your best bet. A dehumidifier is the best option if you live in a humid but cold climate.

In other words, you should weigh the importance of removing moisture with the necessity of lowering the temperature.

If your home is overly humid all year, a dehumidifier is far more efficient than a portable air conditioner with a dehumidifying function. Aside from that, a dehumidifier is usually less expensive.

However, if you only want to combat the dampness in the summer on occasion, a portable AC can do the job and make you feel more comfortable on hot days. You can also save money on buying a dehumidifier.


Many people are aware that portable air conditioners have a dehumidifying function, so it is natural to wonder if a portable air conditioner can be used as a dehumidifier.

Fortunately, you can. Even though the dehumidifying effect is not as good as that of a specific dehumidifier, it can definitely remove some moisture. The reason for this is that both household appliances, let alone some portable AC models with a “dry mode,” use cold coils to condense the water vapor.

To make your portable air conditioner remove more moisture, choose one that is appropriate for the size of your room and consider placing the vent hose in the room if you do not want to cool your room at the same time.

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Liz Yang is the founder of Airsmartly. She has been working at home for a few years and realizes that the performance of the HVAC system plays such an important role in our life. She has tested a lot of products in person, like humidifiers, air purifiers, dehumidifiers, and ACs, and wants to share tips about using or troubleshooting these products with you. Her uncle is an HVAC expert with over 30 years of experience in the field, and often offers assistance when she is unsure how to handle a situation. He is also in charge of reviewing the articles on this site.

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