1 filter included, I believe the service life is specified as 6 months, must be washed weekly

Yes, the Philips HU2510/10 humidifier is very quiet. In gentle sleep mode, it achieves a sound level of just 22.5 dB (A), which is as quiet as a whisper. This makes it ideal for use in bedrooms or other quiet environments. The appropriate filter is available at https://www.galaxus.ch/de/s2/product/philips-filter-fy119030-1-x-zubehoer-luftbehandlung-24717487.

Hello The appliance has a 3 position button speed 1 / off / speed 2 and stops automatically when there is no more water. Speed 1 is very quiet, almost inaudible.

My unit has a 2-pin plug.