Though it's normal for a dishwasher to make some noise, you don't want it interrupting your after-dinner conversation or quiet time. Insulation around a built-in dishwasher reduces the amount of noise your dishwasher makes and is an essential part of the dishwasher installation. If you think that your dishwasher is too noisy, check for insulation and add more.
Your dishwasher should come with an "insulation blanket" that wraps around the part of the dishwasher that sits in the counter. Some novice installers might mistake this insulation for packaging material and throw it away. It is thin and usually made of fiberglass. Since it's made to the exact size of your dishwasher, this is the best option for dishwasher insulation.
Additional Insulation Blankets
If you want more insulation for your dishwasher, you can purchase additional blankets. Look for one that matches the brand of your dishwasher for the best fit.
A built-in dishwasher is meant to fit snugly into your cabinet space. There may not be much room for additional insulation. Before making a purchase, pull the dishwasher out and measure the amount of additional space. Do not purchase more insulation than can fit in your space.
Better Sound Insulation
High-end dishwashers typically come with a thicker layer of insulation to prevent sound. The machine also may feature a higher quality construction that also can reduce noise levels. If noise is an important factor for you, consider purchasing a higher quality machine.