Dishwashers often save energy and water compared to hand washing. Depending on the brand, dishwashers typically consume 7.5 to 12 gallons (28 to 45 liters) of water per normal wash. Hand-washing a day’s worth of dishes may use up to 15 gallons (57 liters) of water. One university study found that dishwashers consume about 37 percent less water than washing by hand.

Several steps can be taken for additional energy savings when using a dishwasher. The setting on a home’s water heater can be turned down to 120°F (49°C) if the dishwasher has a booster heater. While some machines feature a no-heat, air-dry setting, simply opening the door after the final rinse to let the dishes air dry will save energy. Prewashing the dishes before loading generally wastes water since most machines can handle even heavily soiled plates.