Which dehumidifier to choose? Check before you buy


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There are many devices on the market whose task is to dry the air of excess moisture. Their price range is quite significant, as is the functionality itself. Which device to choose so that it works perfectly for what we need it for and that we are satisfied with the purchase? You will learn more about it in this guide. 

Why do we need a dehumidifier?

The task of the dehumidifier is to remove excess moisture from the air. Most people are unable to feel a change in humidity of up to 30% difference. It is assumed that the room should have a maximum of 50 to 65 percent humidity. Air that is too dry can damage furniture, cause a dry throat, cough, difficulty breathing and even irritate our eyes. This is a problem that occurs most often in winter during the heating season – hot radiators and limited ventilation significantly dry the air. However, today’s entry concerns the problem on the other side of this percentage scale – excessive air humidity. I was inspired to write this guide by the recent flooding of my garage near a new housing estate and the need to purchase just such a device. 

The causes of excessive humidity in rooms can be very different. It should be remembered that to a large extent we ourselves contribute to increasing the level of water in the air. We exhale an average of 2 liters of water throughout the day, and when taking a hot shower, drying laundry, cooking – we can notice the mist that covers surfaces such as mirrors. Often, entering a room with poor ventilation, we can smell the characteristic musty smell.

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Meanwhile, excessive moisture is a big problem. It causes the appearance of mold and fungi that are dangerous to health, especially for allergy sufferers. It destroys furniture, wallpapers, fabrics, carpets, makes plaster fall off the walls and efflorescence appears on it. They are often difficult to remove and involve quite an expensive renovation. 

Additional causes may include leaks, flooding, incorrect ventilation of rooms or lack of it, incorrect insulation or thermal bridges. 

Dehumidifiers are designed to remove excess moisture from the air before it becomes a problem. They are also helpful in the event of flooding, more and more often, many people also use them to speed up the drying process of laundry. 

How does a dehumidifier work?

These types of devices literally suck the water out of the air, reducing its amount. However, water does not magically disappear and is most often condensed into a container hidden inside the device or removed outside using a special hose. There are several types of dehumidifiers available in the market. Often you can also find a division into household devices and for professional use, e.g. for construction. 

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Condensing dehumidifiers

These are those that cool the air below the dew point, which causes condensation, i.e. condensation of water. In such a system there is a compressor, heat exchangers, a fan and an expansion element. It works similar to an air conditioner. The fan blows warm and humid ambient air through the radiator, where the water condenses into a special tank. The dehumidified air is blown outside. The efficiency of such devices depends on the ambient temperature and humidity level. Efficiency is greatest at around 30 degrees Celsius and 80% humidity. As the average humidity in the room decreases, the efficiency of condensation dehumidifiers decreases. They will not work at temperatures lower than 5 degrees Celsius. These types of devices are quite popular due to the good price-performance ratio, relatively small size and high durability and versatility.

Absorption dehumidifiers

They are covered with a special silica gel that absorbs water. Unlike condensation dehumidifiers, it is not sensitive to low temperatures. It usually consists of a special drum covered with a hygroscopic substance. The dehumidifier captures moist ambient air and passes it through a rotor where moisture is deposited. The dry air is expelled outside and the process repeats. However, the biggest disadvantage of this type of devices is their high sensitivity to air pollution. It is not suitable for construction or finishing works. It also uses more energy.

Air dehumidifier – what to look for when buying?

There are many devices on the market from different manufacturers, which at first glance differ only in appearance. So what should you look for when buying a dehumidifier?


This parameter is provided with each sold device. In this way, the manufacturer informs about how much water a given dehumidifier is able to collect during the day. In the case of condensation dehumidifiers, we will most often see two parameters: both for a temperature of 30 degrees Celsius and 80% humidity (ideal conditions for such equipment) and for lower parameters, e.g. 25 degrees and 60% humidity. Different performance will be listed here. On the other hand, absorption dehumidifiers have a constant capacity at any temperature above freezing. 

Another parameter worth paying attention to is air flow. It is usually given as the number of cubic meters per hour. The greater the air flow, the greater the efficiency of the device (it will work better and faster). If we put a dehumidifier in a garage that is 16 square meters and 4 meters high, a device with an air flow of 300 cubic meters per hour will replace all the air in the garage almost 5 times. 


Among the features worth considering is the automatic start. Thanks to this, the device will turn on automatically when the humidity in the room rises too much. When the dehumidifier receives excess water, it will turn itself off and resume operation when necessary again. Such a function is useful because it does not require the user to supervise such equipment. It also saves energy and increases the service life of the dehumidifier. 

Another important function is the automatic interruption of operation when the condensate tank is full. Thanks to this, we can leave the device unattended and without the risk that after returning home, the dehumidifier will overflow and flood the room. 

More and more dehumidifiers also have a special laundry drying function. Thanks to this, it turns on its maximum power and the blower to maximally shorten the drying time of the hung laundry. This function can also be useful in places with poor ventilation, small rooms or bathrooms. 

A very useful option is the ability to adjust the power with which the device works. Thanks to this, we can save electricity and significantly reduce noise when the dehumidifier is standing in our bedroom. 


Noise is very important if we are looking for a device mainly for home use. The possibility of adjusting the power and adjusting various parameters, such as fan power, significantly reduces noise. After all, we don’t want to sleep or even spend the whole day with a rather loud device. However, if we buy a device that we will leave in the garage or in a renovated apartment – noise will no longer be such a problem. A useful function is also the night mode, which allows you to turn off unnecessary lighting and displays and significantly mutes the operation of a given dehumidifier. 


Industrial, construction and home dehumidifiers differ significantly from each other. They are distinguished primarily by efficiency, size, method of application (e.g. resistance to dust, etc. and price. There is no point in buying an industrial dehumidifier for home use. On the other hand, some dehumidifiers will not cope with conditions such as construction works. A large amount of dust for home dehumidifiers, it can clog filters and even a cooler. The target size of the room where you want to use such equipment is also important.

Tank capacity

Domestic dehumidifiers have built-in condensation tanks. Most often they have a capacity of 1 to 5 liters. Some models are also equipped with the possibility of connecting a hose (usually included in the set) to the drain from the dehumidifier. Then the device can work continuously as long as the other end of the cable is set to a drain or a larger tank. An important function that almost all dehumidifiers already have is the overflow switch, which makes sure that excess water does not get out of the tank and flood the room. 

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Condensation dehumidifiers for home use range from 250 watts to 500 watts in continuous operation. Those that have a built-in humidity sensor and automatic modes – do not consume so much energy and save money. On the other hand, much more electricity is needed for absorption devices, which consume up to twice as much energy as condensing ones. 

Let me know what you noticed when buying a dehumidifier – I’ll add these elements to the article above.

Jakub Markiewicz
Jakub Markiewiczhttps://jotem.in
Hi, I am the author of the Jotem.in blog and series of thematic portals since 2013. I have nearly 15 years of experience in working in the media, marketing, public relations and IT. If you are interested in cooperation, you would like me to write about something or test a product - let me know.
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