Running the hot water tap beforehand assumes that the dishwasher is hooked up to the hot water in the first place, which isn’t common everywhere.

Where I live this feature is called hot fill, I believe, and a lot of dishwashers don’t even support it. For those that do support its still generally not recommended to use it since the dishwasher now can’t do any rinsing with cold water, which is not only wasteful but I’ve heard the hot water can damage the water softener in your dishwasher.

But if you do hook it up to hot water (which is a lot more common in the US, I think) this makes a lot of sense.

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mitthrowaway2 2 hours ago | parent [-]

And lo, there is verily even more information presented in the video than this thread has yet revealed. For what Alec says in the video is that this purge-the-cold-water advice is specific to North America, and he even explains the reasons why!

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bakje 2 hours ago | parent | next [-]

Haha I have to admit I didn’t watch the whole video.

In which case my comment still stands for those who also haven’t watched the whole video, which is probably a fair amount of people

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krige 2 hours ago | parent | prev [-]

He does mention it has to do with voltage and heating systems. I think it's something he covered on his kettle vid.

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inferiorhuman an hour ago | parent [-]

He mentioned that it's not due to voltage but rather low current circuits. A 15 amp circuit translates to around 1,800 watts in the US and if you derate it to 80% of that like the NEC requires a continuous load you'd have around 1,440 watts available.

His argument is that appliance manufacturers are trying to simplify their lineup by making models that would work in homes without a dedicated circuit (15 or 20 amp). Although I can't think of a better argument that still doesn't quite sound right to me. The NEC has required dedicated circuits for dishwashers for quite a while now and IIRC that requirement has been for a 20 amp circuit for a few decades. Even though you typically only see 15 amp receptacles, kitchens have required 20 amp circuits for somewhere north of forty years.

I think a lot of his video is simply based on testing with crappy Whirlpool and AEG dishwashers. There's a reason why Bosch (and these days LG) dishwashers are pretty much universally recommended.

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Turskarama an hour ago | parent [-]

It's the same issue, if you have a higher voltage then you can get more power without increasing current.

For example in Australia a standard house circuit is 10 Amps, but because it's at 240V we can get 2400 Watts (realistically more like 2300) out of a _standard_ wall outlet that is in every room of your house.

	▲	inferiorhuman an hour ago \| parent [-]
		It's not the same issue. The vast majority of kitchens in the US have 20 amp circuits (so 2,400 watts peak, 1,920 watts continuous) exclusively. It's a bog standard receptacle (NEMA 5-20R instead of 5-15R) that's backwards compatible with 15 amp plugs. In fact these days most 5-15R receptacles have identical guts to their 20 amp counterparts save for the additional provision for a horizontal blade. The electrical code (NEC) has started moving towards requiring 20 amp circuits in other rooms and more 20 amp circuits in kitchens.