It gets noisier, but still acceptable
We've been using this unit for almost 2 weeks now. It is getting noisier.  We are non-smokers and don't have pet so I can't comment on if the air's been cleaned or sanitized. We placed this unit in the 2nd floor bedroom and initially noticed a low humming noise, which was expected.  After about a couple days, the noise got louder because we could hear it from ground floor.  After 10 days or so a couple visitors asked if we forgot to turn off the water upstairs.  If it gets even louder then I will have to return it.<br /><br />I gave it 3 stars because the bedroom air seemed fresher after a night of sleeping with door closed.  I also like it that it can be turn 180 degrees after plugged in. I often let the light pointing downward so the light isn't too strong when I am sleeping.
Rating: 3 stars