[derda]

> Other countries' dishwashers are also connected to the hot water supply.

I think it is more a 110V vs. 230V household power issue. For 110V countries like the US the amps needed to heat up the water would be pretty high or the heat up would take very long. In Europe however I have yet to come across a dish-washer that is connected to the hot water supply.

[eru]

The US actually has 220V available in most households.

[sgerenser]

Yes, virtually all US households have 240V service. But virtually none of them have a 240V outlet where the dishwasher goes.