Earlier quoted context omitted.
American dishwashers don't have their own heater? Some do, some don't. The ones that do vary in ability by overall dishwasher quality. The ones that don't are hooked up to the kitchen's hot water line. This is considered more energy efficient because a home's hot water heater (whether electric, gas, or another fuel) is better at heating the water in a bulk capacity than a tiny heater in the dishwasher. The downside i…
Hot water from the house supply isn't that hot though? My dishwasher gets MUCH hotter than the hot water supply... and I don't think the heater is "tiny" I think it's a rather substantial element. The dishwasher also doesn't need to heat up a "bulk" amount of water, just the amount of water used for washing the current load of dishes.
Also the size of the heating element is irrelevant. What matters is the power dissipated. Most dishwashers in the US will use only about 900 watts of power even when plugged into a circuit that supports 1500 watts. In the EU they often hit 3000 watts. Even when just heating up a gallon or two of water that makes a huge difference.