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Comment by bakje | Hacker News Reader

> Your dishwasher, wherever in the world you may be, will start up by using whatever water it can get for an initial rinse of the dishes, and it will measure how dirty the water is after this initial rinse.

> Normally this water will be tepid. But if you make it hot by running your hot tap first, the hot water will rinse more dirt off the dishes than tepid water ...

I might be misunderstanding you, but this definitely doesn't apply everywhere.

I don't know how this works in the rest of the world, but in the Netherlands at least my dishwasher is only hooked up to the cold water, running my tap will have no effect on the temperature of the water my dishwasher receives.

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I can't speak for every person's experience, but what I believe is that most dishwashers being sold today, anywhere, are capable of being connected to domestic hot water, or cold water. They will work with both. That's not the same thing as saying every dishwasher being sold can do this, but check your instruction manual. Perhaps it can. As per a sibling comment, decide holistically if that would be a good idea or not.

Unless someone can point me to the existence of regulations saying something like "it's illegal to connect a dishwasher to a hot water line, it's gotta be cold water that the dishwasher heats up itself", then my expectation is that most dishwashers can be connected to either hot or cold, and will heat the water to the correct temperature.

Looking at EU regulations, as far as I can see, they don't regulate the intake temperatures that dishwashers have to accept. What they do regulate is energy usage labelling, and mandating there must be an "eco" mode, what the eco mode must do, and if you get to select multiple modes then "eco" mode must be the default. https://commission.europa.eu/energy-climate-change-environme...

> I can't speak for every person's experience, but what I believe is that most dishwashers being sold today, anywhere, are capable of being connected to domestic hot water, or cold water. They will work with both.

This is not my experience. Nowadays appliances such as washing machines and dishwashers, in Europe at least, only have a cold water inlet.

Apparently modern appliances use so little water overall that it's no longer efficient to connect them to a hot water supply, since they will stop drawing water before the hot water runs through the pipes, and therefore it just wastes the hot water.

Many European machines accept hot water. Any Miele does, and my entry level Bosch (in UK) accepts up to 60C but you have to set some obscure setting on the machine (the manual explains). But I find even cheap machines wash pretty well even without this, and you are right about it it being hot only if the machine is right next to the boiler.

I bought a new dishwasher (and it's not as good as the old one :/), in the instruction manual it says you can use some configuration to tell it it's hooked up to hot water.

It makes sense to hook it up to a hot water line, given things like solar collectors and heat exchangers heating / pre-heating water.

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