The sones rating applies to any appliance with an exhaust fan and is a measurement of how sound is perceived by the listener. The lower the sones rating, the quieter the appliance. One sone is equivalent to the quiet humming of a refrigerator, whereas a 4-sone rating would interfere with conversation among a group of people standing close by. If having a quiet appliance is a top priority, you should choose a microwave or range hood with a low sones rating.
Benefit of a low sones rating
Appliances that feature sones ratings