Symbolic image of humidification
Lea Bieri , 21.11.2019

Which is the best system for air humidification? We clarify

A relative humidity level of 40–60% is considered ideal and recommended by doctors and medical experts. During the cold season, the humidity indoors can often drop to 30% or less. The main reason for this is that turning the central heating on significantly increases the difference between the temperature indoors and outdoors. The greater that difference, the drier the air in the room.

To find out whether the indoor climate within your own four walls is okay, you can measure the humidity using a hygrometer. If the indoor air is too dry, a humidifier can rectify this, creating a optimal indoor climate and improving well-being. In our blog article «10 reasons to get a humidifier», we point out when and why you should use a humidifier.

Hygrometer Selina by Stadler Form

Active and passive humidification

Every humidification system has the same goal: to add water to the air. There are four different systems which can be divided into two humidification categories: active and passive humidification.

With active humidification, temperature does not play a role. What that means is that water is added to the air regardless of the room temperature or the current level of humidity. Vaporisers and nebulisers are both types of active humidification systems. The advantage of an active humidification system is that it can increase the indoor humidity very quickly and efficiently. Therefore the devices in this category offer a high level of humidification performance. Active humidifiers are suitable for water with a soft to medium degree of hardness.

With passive humidification, the air is humidified depending on the room temperature and the current level of humidity. What that means is that with this process, the air only absorbs as much humidity as it actually needs based on the current temperature until it becomes saturated. This involves the process of evaporation – a natural process occurring in nature – which is carried out by means of the technology within the evaporator or air washer system. Passive humidification is suitable for all degrees of water hardness and is highly energy-efficient, without causing overhumidification.

The four humidification systems explained in simple terms

The water is brought to boiling point in the appliance using a method similar to the one applied in an egg boiler or a kettle, for example. Boiling the water produces germ-free water vapour which is emitted by the unit directly into the room and distributes optimally into the air.

The sterility of the water vapour makes vaporiser systems particularly suitable for allergy sufferers. When the water is boiling, it makes a soft bubbling sound that can be very relaxing. It is important for limescale to be removed regularly from vaporisers. We advise against using hard water or water from water softeners in vaporisers as the significant limescale and salt deposits would have to be removed from your appliance very frequently.

Humidifier Fred by Stadler Form

Ultrasonic nebuliser
As the name suggests, this type of humidification system turns water into mist. An oscillating ultrasonic membrane in the nebuliser atomises the water, turning it into tiny droplets. A built-in fan in the appliance transports them into the air as mist which humidifies the room air.

In principle, the mist emitted by the device is cold because the water inside it is also cold. This makes nebuliser systems suitable for nurseries. With this system, the process of humidification is made visible due to the mist, which is why these devices are also known as atomisers. Nebulisers are less suitable for use with hard water or water from a water softener. The first one mentioned has a high concentration of calcium which leads to significant limescale deposits in the device, along with the need for frequent removal of deposits. The second one mentions is enriched with a high salt content which can lead to white deposits accumulating around the device. It is very important for all humidifier systems – but particularly nebulisers – to be cleaned and descaled on a regular basis.

Humidifier Eva by Stadler Form

The way that an evaporator works is based on the natural principle of evaporation. The humidifier filters inside the unit are soaked with water. A built-in fan draws the room air inside the unit where it is guided through the moist humidifier filters. In the process, the air absorbs the humidity required according to the current temperature and humidity level, i.e. as it flows through, the indoor air absorbs tiny water droplets and then is released into the room air along with this humidity.

The evaporator system has two main advantages. Firstly, evaporators are very quiet, making them the ideal choice for quiet rooms such as bedrooms or offices, for example. Secondly, overhumidification is not possible with this system as the air is only enriched with as much humidity as it needs and is able to absorb based on the current temperature. With this system, the filters need to be replaced regularly.

Humidifier Oskar by Stadler Form

Air washer
This system is a combination of humidifier and air purifier. The principle of humidification belongs to the category of evaporator systems. The difference lies in the choice of the humidifying medium: the air washer uses permanently usable plastic discs and the evaporator regularly to be replaced paper and textile fiber filters. Air washers are fitted with a disc pack designed specifically to absorb humidity while also clean airborne particles. The discs which are known as humidification discs or evaporator discs rotate in the water. A fan sucks in the dry indoor air which is guided across the rotating wet discs. In the process, air pollutants such as pollen, dust or hair are deposited on the rotating discs. The disc pack continues to rotate and the particles are washed off in the water. The moisture still present on the clean part of the discs, from which any particles have been removed, is emitted into the air.

With this technique, the air is not only humidified but also cleaned from air impurities, making air washers ideal for allergy sufferers. Regular cleaning is important in order to rinse out the water base and remove the pollutants washed from the air.

Basic discs of humidifier George by Stadler Form

You have now been introduced to the four types of humidification system and know how they work. If you are still unsure as to which type of humidifier is right for you, then we recommend you to read the blog post «How to choose a humidifier» or to watch the video below.

Watch the video to find your perfect humidifier


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