It does what it should and the air feels much better. But I really do not know how much more humid the air is because I do not have a good gauge.
It sounds a little bit. Most are rippling water as it circulates water all the time. But the buzz even a little. Nothing that directly interfere, however.
It does not seem to have any warning or auto shut-off when the water is out. This, combined with the level indicator on the side is extremely difficult to read, do you have to look to the drinker. One tank is enough, however, long time!
It is very easy to fill without spillage. No cap that needs to be opened, but only pours the water into the top of it.
I bought mine from Conrad via CDON and the delivered units HH210E4 and seems to be a little stronger than what is listed here. It is 41W and should lead to 24m2. Acc. carton there is a HH210E2 too so I guess it has the lower power given here.