Quiet dishwashers feature insulation to absorb sound, spray arms that point inward and base-mounted motors. Dishwashers equipped with strainers, as opposed to built-in garbage disposals, also run quietly.
American dishwasher models include internal garbage disposals that grind scraps of food, which contributes to a high noise level. European dishwashers have strainers or filters to catch the waste, which allows them to perform quietly. Washing compartments made from stainless steel provide better noise insulation than tubs with plastic casing. European dishwasher brands also include base-mounted motors, which run quieter than the side-mounted motors commonly found in American-made dishwashers. Side-mounted motors are attached to the washing tub, and the tub amplifies the noise caused by vibrations from the motor.
Bosch makes quiet dishwashers that are built with three layers of noise insulation, which are made from cotton, bitumen and stainless steel. Bosch dishwashers feature spray arms that aim toward the dishes, which reduces noise by stopping pressured water streams from hitting the inside walls. The dishwashers also include a molded base designed to trap sound, which minimizes noise-causing vibrations. The motors in Bosch dishwashers are suspended from rubber hammocks that are engineered to reduce vibrations and noise. Bosch dishwashers also feature an EcoSilence motor that is engineered to work quietly without the use of brushes or friction.