The efficiency of a dishwasher is measured by a term called the
energy factor. The energy factor is somewhat similar to the
miles per gallon for a car, but in this case the measure is
cycles per kilowatt-hour of electricity. The minimum allowed
energy factor rating for standard capacity dishwashers is 0.46.
About 80% of the total energy used by a dishwasher goes towards
heating the water. So the best way to improve the efficiency of
a dishwasher is to reduce the amount of water needed to clean
the dishes. New dishwashers use about half the electricity of
25-year-old models. Most new dishwashers have a built-in booster
heater, which raises the water temperature of the water during
wash cycles to 140°F to kill germs and cut grease. While this
feature adds somewhat to the dishwasher's electric demand, it
enables you to lower the thermostat setting on your hot water
heater to 120°F. Each 10°F reduction in the water heater
temperature setting will save up to 13% of your hot water
heating bill and also reduce the d