It's called an insulation blanket and its main purpose is to muffle the noise made during operation. Since it's usually made of fiberglass, it provides some heat insulation too. You don't need it, but you'll probably find the extra noise to be annoying.
Common materials that are used to make dishwasher insulation include fiberglass, felt, foam. Newer insulation materials such as ceramic fiber provide better insulation against sound, heat, and vibration.
Cover the joint between the panel and the existing cabinetry, if it is visible, using caulking or wood putty colored to match your cabinets. Place a bead of paintable caulking all along the seam and smooth it with your finger. Paint if necessary to create a seamless finish.
Insulation around a built-in dishwasher reduces the amount of noise your dishwasher makes and is an essential part of the dishwasher installation. Insulation reduces dishwasher noise. If you think that your dishwasher is too noisy, check for insulation and add more.
A slight gap is necessary to let heat and moisture out without damaging your cabinets. Plus, you may block the dishwasher door from opening.
Make sure there is at least 27 inches of open space in front of the dishwasher for loading and unloading.
2. Tub materials: A dishwasher with a stainless steel tub is generally quieter than dishwashers with plastic tubs. Additionally, sound dampening on the outside of the tub helps to decrease noise.
If water has been leaking through the door the insulation will be wet. If so, replace the soap cup and the rinse aid dispenser. If not the wash arm or wash arm housing may have a hole in them. This will causing water to spray under the door, replace both of them because you may not be able to see the hole.
A standard size dishwasher is made for a kitchen cabinet opening that is 24 inches wide, 24 inches deep and 35 inches high.
Standard Dishwashers
The vast majority of undercounter dishwashers measure approximately 24 inches in width, 24 inches in depth and 35 inches in height with adjustable feet. This means that the rough opening in your cabinets must be 24- by 24- by 35-inch.
Many dishwashers have 1/2" - 3/4" gap or clearance to the counter top. This is not unusual. Many manufacturers require a certain amount of "clearance" to the top of the counter top/sides of the cabinets due to heat and humidity that comes of the machine. That's why I suggested a 1/2" plywood and nothing thicker.
Dishwashers need to have at least 2 feet of space between them and the wall. This is due to how hot the machine can get while it is running and the moisture it emits. Having a dishwasher too close to the wall will quickly result in mold and mildew building up on the sheetrock or paneling.
What is the smallest dishwasher? Compact dishwashers (also known as space saver dishwashers ) are smaller than the traditional 24-inch size. These dishwashers usually measure 18 inches. You can also opt for a single drawer dishwasher with 24-inch width and 17-inch height.
There are three main sizes available, according to width: 18, 22, and 24 inches. The standard dishwasher is 24 inches wide, while the 18-inch and 22-inch options are used mainly to save space in smaller kitchens, such as in apartments or common work/living areas.
Make sure any water has been pumped out of the tub. Cause of Excess Suds: Using the wrong type or too much detergent can cause excessive sudsing. The suds may push water out of the dishwasher causing leaks or flooding conditions. Only detergent specifically designed for use in automatic dishwashers should be used.
Inferior dishwasher soap or soap not designed for use in a dishwasher such as hand washing dish soap will cause too much sudsing. The excess suds build up around the door and can press through the door opening, leaking out past the door.
The suds cause the dishwasher to leak from the door seals and from the water level float.
A rating of 45 decibels or lower is virtually silent — similar to the volume of a low discussion in a library or quieter. Decibel levels between 45 and 50 sound similar to rainfall. Ratings of 50 or higher are equivalent to the level of a normal conversation.
Quietest - 38 dB
And finally, 38 dB is the quietest dishwasher rating on the market as of today.