Any decibel rating lower than 60 is very quiet, with the lowest currently coming in at 43 decibels. Load them up. Some dishwashers allow you to wash as many as 12 place settings per wash. Look for a deep basin with flip-down tines to accommodate pots and big pieces, an adjustable upper rack for tall stemware and salad plates plus movable flatware baskets to accommodate the full load. Make sure it's hot enough for you.
Most dishwashers heat incoming water to fully activate the detergent.
Those listed as certified by the National Sanitation Foundation heat it higher than 150 degrees. This, however, is not long or high enough to meet commercial standards but will give you sanitized dishes, important if you're doing baby bottles or just want to help stop the spread of cold germs around your household. Wash fine china with abandon. To protect the finish on fine china and prevent crystal spotting, look for models offering a lower temperature wash. It doesn't completely activate the chlorine detergent that could damage the design.