The transition of a substance from a liquid to a gaseous state without reaching the boiling point requires energy. The substance draws this from the ambient temperature. This lowers the room temperature. Colloquially, this effect is called evaporation. Our body also makes use of this. When it is hot, sweat forms on the skin, which evaporates and cools. If there is some wind, for example through a fan (purchase advice), evaporation is further stimulated.
Now there are more and more inexpensive fans on the market that distribute fine water particles in the air, which then turn into a gaseous state. This increases the humidity and lowers the temperature. In buildings, especially well-sealed new buildings that already have a problem with too high humidity, they should not be used or only with the window open, which in turn reduces the cooling effect ad absurdum at high outside temperatures. In such environments, a dehumidifier (advice) or a split or monoblock air conditioning system (purchase advice) can help.
Evaporative coolers are cheap and comparatively mobile. You do not need a permanent installation such as split air conditioning systems and no hose leading to the outside for the exhaust air such as monoblock air conditioning systems. Usually there is a bowl for the water, which is pumped out and atomized and sprayed in front of a fan. This distributes it in the room.
The cooling effect is measurable. We position a digital temperature sensor half a meter away in front of various evaporative coolers: the powerful Honeywell CS10XE, the two tower fans Sichler 3in1 WLAN air cooler LW-480.wlan and VT-560.app as well as the Sichler WLAN standing spray fan VT -480.app. The following values are comparable for the devices; we limit ourselves to the Honeywell CS10XE as an example.
With the air cooler switched off, we measured 24.1 degrees. If we switch on the ventilation function, the temperature drops to 23.4 degrees after 30 minutes. If we now activate the cooling function, i.e. the spray mist with evaporation effect, the temperature is reduced to 20.4 degrees. These 3 degrees compared to pure ventilation are clearly noticeable. You immediately have the feeling of a refreshing and cooling breeze. This not only works in rooms, but also to a limited extent on balconies or terraces. Here, however, you should rely on a device with sufficient performance.
In the second test, we want to know how much an evaporative cooler cools down an enclosed space of around 20 square meters. Here the cooling effect is much less clear. None of the devices managed to lower the temperature of the room by more than one degree after cooling for an hour. After two to three hours, the opposite effect even set in. The temperature rose again slightly. Above all, you felt like you were in a sauna. The high humidity ensures that the perceived temperature appears higher than it actually is. Evaporative coolers, regardless of the price range, are unsuitable for actual room cooling. After all, the room is largely a closed system. If the temperature is to drop sustainably, an air conditioning system with an exhaust hose is required. However, putting ice cubes or cooling packs in the water can help.
Evaporative coolers should be cleaned regularly. Bacteria can form in the water tank and spread through the air via the fan. If you feel a biofilm on the inside of the tank, which is covered by water, cleaning is urgently required. In addition, limescale should be removed from the devices regularly in areas with hard water. Regular cleaning with a little vinegar helps against both bacteria and limescale. Some users even add a few drops of vinegar to the water.
Evaporative coolers are cheap, the first models cost less than 20 euros. Mostly they use a USB port for power supply, which makes the small fresheners particularly suitable for the desk. In them there is a wet pad in a water container, past which a fan blows a stream of air. The liquid evaporates and cools the air a little.
In most cases, they offer multiple speeds. The lowest should be quiet enough to run on the bedside table on very hot nights in the bedroom without disturbing sleep. In the following we show the cheapest table fans.
Pedestal fans with air coolers start at around 70 euros, but can also cost over 200 euros. As an example, we took a look at the Sichler WLAN stand-alone spray mist fan VT-480.app, which costs just under 150 euros at Pearl. They have a major advantage over tower fans with a cooling function: they are usually quieter in operation. We can confirm this in the test: at the lowest level, the fan scoops air through the room with a quiet whirring sound. If you switch on the humidification function, it gets a little louder. Nevertheless, the Sichler VT-480.app is one of the most affordable air coolers. When the humidification function is activated, atomized water emerges in the middle in front of the fan and is distributed throughout the room. This is clearly visible as a fog and a pretty cool effect.
Visually, the Sichler VT-480.app takes getting used to, colleagues compare it to a robot from the Star Wars parody Space Balls. His foot is knobbly, it is somewhat reminiscent of an oversized drop of water. The spray mist device with the black hose looks like a trashy copy of the Darth Vader mask. Elegant is different.
If required, the Sichler VT-480.app can be connected to the WLAN at home, has its own app and reacts to Alexa and Siri voice commands. Its fan head has a diameter of 40 centimeters. It shouldn’t be smaller either, otherwise the noise development will increase. If desired, it automatically rotates horizontally back and forth at a 90 degree angle. When buying, you should pay attention to this function called oscillation, as it distributes the cool air better in the room. Its water tank holds just under four liters. We do not recommend buying a device with a significantly smaller tank, otherwise it will have to be refilled too often.
Most large evaporative coolers come in a plastic box, similar to a tower fan. This makes them more compact than the fans with air coolers discussed above, but also louder. We looked at the Honeywell CS10XE, the Sichler 3in1 WLAN air cooler LW-480.wlan and the VT-560.app.
The Honeywell does a lot of things right. It is quite powerful at 100 watts, has a large ten-liter water tank, the air oscillates at a 90-degree angle and comes with an ionizer to improve the air quality. Still, it has two major drawbacks. For one thing, it doesn’t have any smart features. Given its price, we would have liked to be able to control it using voice commands. Nothing. The second and much more important point: The Honeywell CS10XE is really loud even at the lowest level. Sleeping next to him will not be possible for many. Even when watching TV, the humming noise is annoying.
The somewhat smaller Sichler LW-480.wlan is less powerful with 65 watts, but quieter. Even if not as quiet as a fan with a cooling function. Its tank holds four liters, an ionizer is supposed to clean the air, the swing function reaches up to 60 degrees. In contrast to the expensive Honeywell CS10XE, it listens to Alexa and Siri, and it also comes with its own app.
The Sichler VT-560.app also listens to Alexa and Siri and also has its own app. Thanks to a motor, it offers real oscillation of up to 45 degrees. An LED display shows the current room temperature. A dust filter is designed to filter dirt particles out of the air. The manufacturer specifies its evaporation volume at 322 milliliters per hour. However, the water tank only holds two liters.
Inexpensive evaporative coolers also bring something – if you sit right in front of them. The evaporating liquid provides significantly more cooling on particularly hot days than a fan without a water atomizer. However, the evaporative coolers are unsuitable for reducing the overall room temperature. Real monoblock air conditioning systems (purchase advice) would then have to be found here.
Anyone who wants to use an evaporative cooler in the office, for example, could be happy with a table fan with a cooling function, precisely because their purchase price is very low, sometimes under 20 euros. If a big solution is needed, tower evaporative coolers are usually more stylish, but unfortunately also significantly louder than fans with a water atomizer. In both categories you have to reckon with a stake of at least 50 euros.