You can choose between built-in, portable, full-size, and compact models. Measure the space you have available for the new dishwasher and take the dimensions to the dealer.
The best way to reduce sound is to add or improve insulation around the washing tub, door, toe panel, and access panels. Some models offer extra-quiet motors and vibration-absorbing materials, but you will pay more for those features.
If you always choose the highest wash cycle, you'll use more hot water and energy. There are many energy-efficient dishwashers with several available cycles for different types of loads. A delayed-start control lets you wash during less-costly off-peak hours. Read the Energy Guide labels for operating costs.
Angled control panels, large digital displays, wide push buttons, and soft-touch electronic controls are helpful. Consider elevating your dishwasher 12-18 inches to minimize bending as you load and unload. Be sure that detergent and rinse additive dispensers are large enough and conveniently located.
High-performance dishwashers have two or three spray arms that soak dishes with water from several levels and angles. In the spray arms, smaller holes tend to emit a more forceful spray. A central wash tower may improve washing performance, but you'll lose some rack space. A twin-pump system drains dirty water faster than a standard single pump.
Dish and glass racks are basically metal wires coated with nylon or vinyl. The tops of tines wear first, so check the coverage in those areas. Adjustable-height racks add flexibility. If you like to entertain, you'll appreciate models that hold 12 place settings (most hold 10). Special baskets, hooks, and trays are designed for knives, cooking utensils, and lightweight plastic items that might fly around during washing.
Dishwater tubs are made from plastic, porcelain-enameled metal, or stainless steel. Plastic resists chipping and rusting better than enameled metal, but it can discolor. Stainless-steel washtub interiors are durable and easy to rinse and clean, and the finish resists nicks, chips, stains, and odor buildup. Stainless steel stands up to abuse, so it looks new for a long time, and its natural sheeting action saves drying time.