Contrary to the positively expressed opinion of others, I find the noise that the part makes in night mode and level 1 really annoying, i.e. I hear the even clearly visible imbalance of the apparently only cheap plastic fan wheel - which possibly bends differently depending on temperature and humidity, which steel would not do so much and of course would also be more durable.ergo, it doesn't make a continuous sound, but a constant up and down--taken exactly, probably back and forth, Doppler effect and blaaa--with every rotation, is this the same with you--I'm only talking about level 1 and night mode, just to make it clear again, since somehow you always get answers to everything else here than you actually asked--?
It's "quiet" in itself, but it's not a constant, unobtrusive, bearable sound, but rather an annoying "up and down" sound. Do you also notice this with your device, or do I have a model that I should possibly return? 0.o
If I look at the edge of the fan wheel from above, I can even see how the thing is wobbling -- of course less than a millimetre, but still--, so I think that with today's industrialisation, you shouldn't be able to get fans that aren't perfectly round and unbalanced.So I just wanted to ask you quickly, do you also see this with your devices, how the edge always moves in and out a bit to match the annoying sound it makes at the slightest steps?
Do you have to accept this on a "Pro" model nowadays? 0.o It doesn't do me --and the pollution-- any good to go through the whole return procedure and then get back a device that is exactly the same - or, as is so often the case, even shittier, if they were all like that...
@Galaxus & @Digitec: For such cases it would be useful if you could post audio or video files here, so that others could compare it with their device, or that you can hear samples from others before you even buy a device! ;)
If the fan has an audible imbalance at low speed, then there is something wrong with the unit and it should be replaced. I have been using these air purifiers for many years and they have to be absolutely quiet in the automatic mode, nothing should hum or rattle.
However, I have already had two such air purifiers that made a humming noise for a few seconds at intervals of about 10 - 15 minutes, even when they were switched off. However, this did not come from the main fan but from the small fan that is installed in the particle measurement sensor. At first I couldn't explain where this noise was coming from, but then I found the references to the particle measurement sensor on the Internet. I ordered a new sensor from Aliexpress, which is super easy to replace, and since then it has been quiet again.
Back to the problem with the imbalance, something is wrong and the unit should be replaced. They should not be audible in the low setting. If the air purifier can be heard for a few seconds at intervals of approx. 10 - 15 minutes (sounds like an up and down hum), then it is the small fan in the particle measurement sensor. I would change the unit and then take the normal Air Purifier 4, the Pro is not absolutely necessary. Maybe even two 4 Lite are better, I also use two (older 3H), one is in the living room and one in the bedroom.
