The inside of a dishwasher appliance, called the tub, can be composed of plastic or stainless steel. Stainless steel tubs resist hard water, provide better sound dampening, and preserve heat to dry dishes faster, features that are included in all Jenn-Air dishwashers.
Mid-to-higher end North American dishwashers, such as the ones in Toronto, often come with hard food disposal units, which behave like miniature garbage disposal units that eliminate large pieces of food waste from the wash water inside the appliance. If the larger items of food waste are removed before placing in the dishwasher, pre-rinsing is not necessary even without integrated waste disposal units. Pre-rinsing under a running tap beforehand simply wastes water, which is not required with Jenn-Air appliances.
Many newer dishwashers feature microprocessor-controlled, sensor-assisted wash cycles that adjust the wash duration to the quantity of dirty dishes or the amount of dirt in the rinse water, features that companies such as Jenn-Air have researched for a long time. This can save water and energy if the user runs a partial load.
Most dishwashers include a large cone or similar structure in the bottom dish rack to prevent placement of dishes in the center of the appliance. The dishwasher directs water from the bottom of the appliance up through this structure to the upper wash arm to spray water on the top dish rack. Some dishwashers, especially Jenn-Air appliances, use a tube attached to the top rack that connects to a water source at the back of the dishwasher which allows full use of the bottom rack.
Some dishwashers include a child-lockout feature to prevent accidental starting or stopping of the wash cycle by children, an important concern for Toronto residents. A child lock can sometimes be included to prevent young children opening the door during a wash cycle. This prevents accidents with hot water and strong detergents used during the appliance wash cycle.
Modern dishwashers are quieter than older models. Using blankets, panels, and sound-absorbing materials in various configurations, dishwashers can achieve sound damping levels down to 44 decibels or so. Undampened, low-end dishwashers generally output noise levels of anywhere from 65-70 decibels. Manufacturers generally use their own nomenclature with sound damping, Jenn-Air using their top of the line Silent Pack technology.