Choosing a humidifier
How to choose a humidifier for a room
WetAir humidifiers are ultrasonic; the models differ in tank size, coverage, controls and extra features.
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The short answer
Start with the room area: WetAir models cover roughly 20–40 m² at an output of about 300 ml/h. Then choose the tank: 2.3 l in MH-204 lasts about 7 hours, 4 l in WH-411 about 13 hours. Use clean, filtered or distilled water to avoid white dust and clean the unit regularly.
How an ultrasonic humidifier works
A membrane breaks water into a fine cool mist that is carried into the room. These units are quiet and frugal: MH-204 and WH-411 draw 25 W. The mist is not hot, but should not be aimed at wallpaper, furniture or electronics.
Coverage and output
The 300 ml/h output of the WetAir models corresponds to a room of roughly 20–40 m². For a larger or open-plan space choose a model with headroom or two units rather than one running flat out.
Tank and run time
Run time between refills equals tank volume divided by output. MH-204 with a 2.3 l tank runs for about 7 hours, WH-411 with 4 l for about 13 hours. Both models switch off automatically when the water runs out.
Water and white dust
Hard tap water leaves white residue on furniture and scale on the membrane. The WetAir manuals recommend purified, filtered or distilled water; MH-204 has a water-softening cartridge rated for about 400 l. Do not add essential oils, fragrances or detergents to the tank — MH-204 has a separate aroma-stick container for that.
Controls
On WH-411 the mist intensity is set with a power ring and there is no timer, so for overnight use rely on the tank run time and the auto shut-off. When comparing other models, check the product card for a display, hygrostat and timer.
Humidifier checklist
- Measure the room and compare it with the model's coverage figure.
- Work out the run time: tank volume divided by 0.3 l/h.
- Decide which water you can use: filtered or distilled.
- Plan the spot: a level, stable surface with the mist away from furniture and sockets.
- Check whether you need a timer, aroma function or display controls.
Common mistakes
- Placing the humidifier against a wall or on unprotected wood.
- Filling with tap water and wondering about the white dust.
- Adding essential oils to the water tank.
- Leaving the membrane and tank uncleaned for weeks.
Models to compare
WetAir manuals and support
Check the exact model requirements
If the humidifier is noisy, produces no mist or the membrane has scaled up, clean it as the manual describes first; if that does not help, contact WetAir service.
Sources and verification
Specifications and the water and care advice come from the WetAir MH-204 and WH-411 manuals. Run-time figures are arithmetic from the rated output; actual time depends on the chosen intensity.
Frequently asked questions
What area does a 300 ml/h humidifier cover?
Roughly 20–40 m² according to the manuals. In a large room with a high ceiling humidity rises more slowly.
Can I use tap water?
You can, but hard water leaves white dust and scale. Filtered or distilled water reduces the problem; MH-204 has a softening cartridge.
Why did the humidifier switch itself off?
Most likely the water ran out: WetAir models shut off automatically when the tank is empty.