Last updated: August 9, 2021

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A good ultrasonic humidifier increases the humidity in the room where it is installed to a comfortable level. This function brings pleasant effects that should have a relaxing effect on your everyday life. The product world of humidifiers is still quite new and is currently very trendy, which is why new types and ways of humidification are being developed all the time.

One is rather inexpensive or the other rather efficient, so it is not wrong to get an overview. With our big test on ultrasonic humidifiers 2021 we give you a broad overview of ultrasonic humidifiers. We have compared many ultrasonic humidifiers on their advantages and disadvantages to help you find the right ultrasonic humidifier for you. Of course, we hope that this article is helpful for you, whether it is purely informative or related to a possible purchase.


  • Ultrasonic humidifiers create a higher humidity in your home which can bring many benefits, such as minimising dust in the air or small health benefits like less dried out skin.
  • Actually, you can probably distinguish between four different humidification options, which are evaporation, nebulisation, vaporisation and air washing.
  • Nebulisation is the method we would like to take a closer look at in this article. It is currently in vogue and is also the newest method of humidifying the room.

The Best Ultrasonic Humidifier: Our Choices

Ultrasonic humidifier: purchase and evaluation criteria

Of course, it is important to know which criteria can make the purchase decision easier. Especially for inexperienced customers it should be a great help to know which evaluation criteria are important for humidifiers that work with ultrasound. In the following, we have therefore listed the most important 5 evaluation criteria for humidifiers that work with ultrasound:


The performance of an ultrasonic humidifier is a very important, although not so easy to answer, topic. It is not so easy to answer because the output of humidifiers can generally be stated in two different ways. This is because the manufacturer is not given any specifications for standardisation, which is why the specifications can vary from manufacturer to manufacturer.

The capacity is either related to the room size in square metres, whereby an average height of 2.40 metres should be taken into account. With a lower ceiling, for example, a lower output would be recommended.

The other possibility is to specify the output in g/h, i.e. grams per hour. For a rather small room, 100-200 g/h are sufficient, but for a larger room, an output of 300-400 g/h would be recommended in order to achieve efficient humidification.


The volume of an ultrasonic humidifier is a particularly important evaluation criterion if the device is to be located in a sleeping or resting area. No matter how good the humidifier may be, if it is going to deprive you of sleep, the same would be inadvisable.

Ultrasonic humidifiers with an additional aromatic function are also very popular in meditation or massage rooms, as they can contribute to relaxation.

However, a distinctive background noise can also have a disturbing effect on the atmosphere. Here, 30 dB is a volume you can aim for. If this hum is still too loud for you, it is recommended that you look for a device with an additional night mode. In general, however, the most powerful units are usually the ones with the highest noise level.


The size of an ultrasonic humidifier should be taken into consideration, especially the size of the tank. By now, the size of the tank is actually always included in the running time of a device, whereby an ultrasonic humidifier with strong performance and a long running time needs a correspondingly large tank to guarantee this.

In the end, it is not the size itself that is a decisive factor, but the size of the tank alone.

A running time of about 20 hours is not bad here, as the germ load of a device is related firstly to the frequency with which you clean the device and secondly to how often the tank of the ultrasonic humidifier is changed.

Power consumption

With an average power consumption of about 30-40 watts, an ultrasonic humidifier compares very favourably with its alternatives. Nevertheless, excessive power consumption is usually unnecessary for a humidifier, which is why the average just mentioned should provide a good orientation for this criterion.

Additional features

Although not a must, additional features such as an extra-quiet night mode are of course attractive. In addition, some ultrasonic humidifiers have a built-in hygrostat for setting the relative humidity in the room, which enables precise adjustment of the humidifier.

A timer, on the other hand, is also a possible feature of an ultrasonic humidifier, so that the device switches itself off after a certain time during your absence, and the aromatisation of the room also expands the application possibilities of an ultrasonic humidifier.

Ultrasonic humidifier: frequently asked questions and answers

Ultrasonic humidifiers, or humidifiers in general, are still a fairly new product branch. It is therefore not surprising that there are many questions about this product. We will now answer the most frequently asked questions in order to better prepare you for a purchase or just to give you a better insight. Here are the most important questions:

What is an ultrasonic humidifier?

An ultrasonic humidifier is a humidifier that uses ultrasound to influence the structure of the water. Through this sound frequency, which is inaudible to us humans, tiny droplets can be detached from the water mass in the tank, depending on the intensity.


A compact humidifier provides a more pleasant indoor climate in your household.
(Image source: Anke Sundermeier / pixabay)

This leads to the mist that is produced by the device. This mist spreads bit by bit in the room and thus increases its humidity. If you add fragrance oil to an ultrasonic humidifier that is compatible with fragrance oil, a pleasant, discreet fragrance spreads in the room, which promises a calming effect.

What types of ultrasonic humidifiers are there?

We have split ultrasonic humidifiers based on the fragrance component. It is very difficult to identify many different types of ultrasonic humidifiers, as they themselves represent a subspecies of the various humidification options.
Type Advantages Disadvantages
Humidifiers Without attention to this additional function, pure humidifiers are usually better equipped. They usually have a larger tank, a longer average operating time and a higher output pure humidifiers do not have the option of adding a pleasant fragrance to the room, which is the biggest disadvantage. In addition, they usually have a more complex design, which makes them more difficult to clean and less compact
Humidifiers with essential oils humidifiers with this focus are usually more compactly built and much easier to clean. They are also usually less expensive. In addition, they usually have a plus in terms of lighting options or general aesthetics, although this is of course subjective additional features such as a hygrostat are almost never installed and they cannot compete in terms of performance either.

If you're looking for a smaller humidifier, it's more convenient to look for an ultrasonic humidifier right away, which allows you to use essential oils. With larger humidifiers, it's important to look for this, as it's usually a minor feature on the larger units.

However, the table listed here is not meant to make it seem as if no large device allows you to use essential oils. Mostly, however, in-house fragrance pads are used here.

What does an ultrasonic humidifier cost?

An ultrasonic humidifier is usually not expensive. However, there are a few exceptions, as a built-in hygrostat naturally increases the price. In addition, there are very different sizes, which makes the price vary even more from device to device.

The subdivision of the table refers to the focus of the device, as large humidifiers usually do not have compatibility with essential oils.

Type price range
Diffuser approx. 18 to 40 euros
Humidifier approx. 30 to 90 euros

What alternatives are there to an ultrasonic humidifier?

An ultrasonic humidifier mists your home to increase the humidity of your household.


Essential oils are a pleasant addition. An evaporator also provides a pleasant scent in the room.
(Image source: CK Khalon / pixabay)

This method is the latest of three commonly used humidification methods. Here we briefly present the other two alternatives.

The air washer; The last of the three options draws in the air by means of a fan, passes it through a water bath and then releases it back into the room. It is a very good alternative, but the unit needs to be cleaned often because it has a high limescale build-up.

Alternative Description
The vaporiser The vaporiser uses heat to convert liquid into steam, which is distributed in the room. It is a very hygienic method, but also a rather expensive device in itself and also an electricity guzzler.
The evaporator This alternative humidifies the room in a natural way and efficiently filters germs and dust from the air. However, the evaporation is very low compared to the other options.

The biggest advantage of an ultrasonic humidifier is the energy consumption of the device and the volume of the same, as the sound itself is beyond our hearing range. They are also quite inexpensive in comparison.

How do I clean an ultrasonic humidifier?

An ultrasonic humidifier is usually very easy to clean. In addition to the cleaning options in the respective operating instructions for your product, we recommend wiping the device with a cloth dipped in white vinegar to effectively remove limescale stains or oil residues.


Many compact humidifiers have a removable cap, which makes cleaning the product very easy.
(Source: Devanath / pixabay)

Afterwards, the device should be thoroughly washed again without vinegar to avoid keeping the smell of vinegar in the device. Alternatively, some sources also refer to citric acid, although it is recommended to use it sparingly There is nothing else to look for in an ultrasonic humidifier, as the tank is usually easy to remove.

Where do I set up an ultrasonic humidifier?

An ultrasonic humidifier can generally be placed anywhere as long as there is some space around the device.
If the humidification does not exceed 70 %, this is not a problem

However, it should be said here that the surface should be water-resistant, as unintentional water splashes can occur when the unit is filled.

For this reason, it is best to place your machine on a shelf or a rack, as this prevents the mist from driving directly into your nose before it can spread, but also prevents the machine from endangering surrounding sheets of paper.

What water do I use for an ultrasonic humidifier?

An ultrasonic humidifier can be filled with normal tap water. However, salt water is not recommended.
Distilled water is of course also suitable, but it is not a must.

An additional tip is to thoroughly inform yourself about whether and how you can introduce fragrance additives to your ultrasonic humidifier.

Many humidifiers have extra fragrance pads for an in-home aroma, others allow for direct delivery of essential oils, but some units are not designed for delivery of such aromas. Failure to follow such instructions may limit the operation of the unit or cause long-term damage.

How healthy is an ultrasonic humidifier?

In the meantime, ultrasonic humidifiers are actually no longer harmful to the health of a normal consumer if used properly. However, allergy sufferers should be especially careful when buying and using the device. In the past, there were products on the German market that carried an above-average number of germs into the air. Even today, with water contaminated with germs, it cannot be ruled out that these germs get into the room air.

Finally, an ultrasonic humidifier lowers the temperature in the room through the cold mist produced, which could possibly be a factor in heating.

In addition, limescale deposits in the form of dust can adhere to furniture, which is not harmful to health, but rather annoying. With regular cleaning, however, such problems are easily overcome.


Ultrasonic humidifiers are designed to make your everyday life more pleasant and provide a more comfortable indoor climate in your home. The way of working with ultrasonic humidification is not only very modern, but also quite cheap compared to other alternatives and also very quiet and efficient. It is important to consider whether you would like to have the option of adding a subtle scent to your room, which increases the relaxation factor.

All in all, there are three other alternatives apart from the ultrasonic humidifier, which, like the ultrasonic humidifier itself, have their advantages and disadvantages. Most importantly, an ultrasonic humidifier is easy on your wallet, works very quietly, which is great for your bedroom, and is very efficient, both in terms of plug-in and power.

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