Commercial dishwashers are considered to be one of the largest water and energy consumers in the commercial kitchen, often using more than two-thirds of the overall water use. The equipment can vary widely in size and shape. Classes of commercial dishwashers include under counter, stationary rack door type, rack conveyor machines and very large flight type (continuous conveyor) machines. Each of these product classes may employ single or multiple wash tanks, and use hot water (high-temp machines) or chemicals (low-temp machines) to achieve final rinse dish sanitization.
All commercial dishwashers have at least one tank that provides hot water with a temperature ranging from 110°F to 140°F (43.3 C to 60 C). High-temp machines require an additional booster water heater to provide sanitizing hot water above 82.2°C (180°F) during the rinse cycle. Lowering the rinse water consumption not only saves water, but also presents the most significant opportunity for energy savings for this product. The gallons/rack rating is a function of water use (in gallons per hour) and wash, rinse, dwell, and load time.
Since the life expectancy of a commercial dishwasher is 20 to 25 years, high efficiency units offer the potential for substantial energy and water use savings. The minimal extra cost for efficient dishwashers over standard models suggests a total lifecycle cost for efficient models is always a wise investment when a commercial consumer is already planning to replace the dishwasher.