The secret is the fan
When purchasing an Air Purifier it is important to consider the operational sound levels, particularly when it is to be used in a quiet space, such as a bedroom. With the newly developed fan and non-clogging Electrostatic HEPA filter this ensures noise free operation, not only in 'Silent'-mode but also during 'Turbo'-mode.
The MC55W presents no mechanical noise, as all you will only ever be aware of is the sound of air moving smoothly through the Air Purifier as the fan motor is actually an inverter driven fan which means that the motor is driven by Direct Current rather than AC Current. This results in a fan motor that has "no whine" that would normally be associated with an AC motor operation. This also means the Daikin MC55 is completely stable & vibration free.
In normal use you would set the Air Purifier to the "Auto" mode. Depending upon what the Air Purifier senses in terms of particles or odours the Air Purifier will adjust its fan speed accordingly, settling back to a low speed once good air quality has been achieved.
Daikin MC55W sound pressure level measured in dBA
Air purifying operation - Silent/ Low/ Medium/ Turbo dBA 19 / 29 / 39 / 53
Remember that a 3dBA increase is a doubling of sound so before you decide on which air purifier to purchase it is wise to consider the minimum sound levels you can expect, so do check manufacturers specification.