I've had this filter for about two months.  At first I loved it--attractive, quiet, and efficient on the automatic cycle.  It's in my bedroom and the light is almost always blue (indicating clean air) but turned amber when we blew out candles, which gave me faith it was working.  However, two months in the noise has changed from a pleasant almost inaudible hum to a quiet but noticeable whine--kind of like an old fridge.  I'm hoping customer service has a solution.