Role of Insulation
Your home has insulation in the walls and possibly the attic to keep the air inside it cool during the hot summer months and warm during the cold winter months. While insulation helps maintain the temperature in a defined area, it also can muffle noise. Some dishwashers come with insulation wrapped around the exterior of the machine, but it is hidden from view after you install the dishwasher under the counter. The thicker the insulation on the outside of the dishwasher, the less noise from inside the dishwasher you will hear.
Fixing Noisy Dishwashers
A noisy dishwasher produces annoying or disturbing levels of noise while it is washing or rinsing dishes. Add insulation to the outside of the dishwasher or inside its front panels to try to reduce the noise. If you find that your dishwasher has insulation on the exterior or in the front panels, install a higher-grade insulation in place of the old insulation to further reduce or eliminate any noise the dishwasher produces while it is running.
You must move the dishwasher out from under the counter to wrap insulation around its exterior. This might involve disconnecting the water supply line if it impedes the dishwasher’s removal from under the counter. Always take care when moving the dishwasher across the kitchen floor, especially if it is made of vinyl, since dragging the dishwasher might lead to floor damage. Cut a piece of insulation that fits only over the sides and top of the dishwasher; applying insulation around the motor can cause the motor to overheat and fail. Keep the insulation in place by applying construction adhesive between the insulation and the dishwasher.
The dishwasher should have insulation behind a couple of its panels, which serves to dampen the sound of the dishwasher running. Remove the dishwasher door’s front panel by removing the screws on the door perimeter and then lift the panel up and off the machine. Remove the screws on the panel on the bottom of the front of the dishwasher by backing out the screws holding it in place and then pulling the panel toward you. If any insulation is present behind either panel, use the insulation as a template when cutting the new insulation.
While the insulation on the outside of the dishwasher keeps the noise level down while the dishwasher is running, the tub liner also plays a role in reducing noise. The liner is the material that is on the sides, back, top and bottom of the dishwasher’s interior or tub. A thin material like plastic does not muffle as much noise as a thicker and more rigid material like stainless steel. You can't change a dishwasher's tub liner.