> Even if it's too high, it's not wasting compared to electrical heater, but possibly it break dish washer Why would it break the dishwasher? It would need a c

> Even if it's too high, it's not wasting compared to electrical heater, but possibly it break dish washer Why would it break the dishwasher? It would need a cold intake aswell, and to measure the water temperature on intake and mix it with cold water to get to the right temperature. > If it's too low (but not cold), then just additionally use electric heater in dish washer So now you need a hot water supply, _and_ an extra electric heater? That sounds like a bunch of extra complexity. > Still efficient than just heating cold water by electric heater. Electric heaters are remarkably efficient, and a dishwasher is likely well insulated. They're often closed loop systems, reusing the same water for the entire wash. The first dishwasher I found (for £350) on a national retailer advertises using under 10L of water, and 0.75kWh of energy per cycle. That's practically nothing.