A dishwasher is defined by DOE as a "cabinet-like appliance, which, with the aid of water and detergent, washers, rinses, and dries (when a drying process is included) dishware, glassware, eating utensils, and most cooking utensils by chemical, mechanical and/or electrical means and discharges to the plumbing drainage system."
Federal dishwasher standards were established by the National Appliance Energy Conservation Act of 1987, building upon earlier state standards. The original standards, which took effect in 1990, required that units have an option to dry dishes without heat. DOE set the first performance standards for dishwashers in 1991, which took effect in 1994, specifying an energy factor (EF) in cycles/kWh. Since that time, dishwashers have been included in two consensus agreements between manufacturers and efficiency advocates. The first agreement became part of EISA (Energy Independence and Security Act), which was enacted in 2007 and required an increase in the minimum energy efficiency of residential dishwasers and set the first-ever water efficiency standards. Standard-size dishwashers manufactured on or after January 1, 2010 must not exceed 355 kWh per year and 6.5 gallons of water per cycle and compact units must not exceed 260 kWh per year and 4.5 gallons per cycle. The second consensus agreement was negotiated in 2010 and formed the basis of DOE's May 2012 final rule. Standard-size dishwashers are required use no more than 307 kWh/yr and 5.0 gal/cycle; compact units no more than 222 kWh/yr and 3.5 gal/cycle. The standard took effect in mid-2013.
The standard is estimated to reduce energy use by 14% and water use by 23% compared to the current dishwasher standards. Consumers of dishwashers that meet the new standards can expect to save about $100 in lower energy and water bills over the life of product compared to today’s basic models. Lower utility bills will offset additional upfront costs within about two years.