then_three_more@lemmy.world 2 weeks ago
Is this an American thing? Dishwashers run off the cold water and heat it up themselves over here.
then_three_more@lemmy.world 2 weeks ago
Is this an American thing? Dishwashers run off the cold water and heat it up themselves over here.
Rivalarrival@lemmy.today 2 weeks ago
Plumbing code in the UK (and parts of Europe?) allowed/allows hot water tanks to be open to the atmosphere, to prevent boiler explosions. The specific tanks in question are filled via float valve, much like a toilet tank. Being potentially exposed to airborne bacteria, fungi, and other biological material, water out of these tanks is not considered potable. If you have one of these atmospheric pressure heaters, you shouldn’t consume the water, or clean cookware, dishes, and utensils with it. Because they might be installed in buildings with atmospheric pressure hot water, dishwashers in areas with atmospheric pressure hot water tanks are designed to be connected to the potable, cold water supply, rather than a potentially contaminated hot water supply.
US does not allow atmospheric pressure hot water tanks. US tanks are under positive pressure, using T&P valves to protect against excess pressure and boiler explosion. The water in US hot water tanks is considered potable. Dishwashers in the US do have heating elements, but they are designed to be connected to a hot water supply.
This is also why UK taps typically have two spouts. The cold water side is pressurized; the hot water can be gravity fed. This causes two problems: 1. If there is any restriction in the output, cold water can backfeed the hot supply and overfill the hot water tank. 2. non-potable hot water can contaminate the cold water in a mixing valve, rendering the cold water non-potable as well.
Rothe@piefed.social 2 weeks ago
It has nothing to do with that. It is about the electrical system in the US not being able to supply water heaters in dishwashers and washing machines. Also the system you are describing is certainly a UK-centric one.
Rivalarrival@lemmy.today 2 weeks ago
That is a myth arising from US typical residential circuit standard being 20A @ 120V, or 2400W.
Major appliances are not limited to this typical standard. US/Canada have code for and commonly install dedicated 30A@120V, (commonly used for large through-window air conditioners) as well as 240V circuits rated from 20A to 80A. The North American electrical system typically provides 200A @ 240V to the residence. That’s sufficient for heating hot tubs and in-ground pools.
No, the decision to use hot water instead of cold water arises primarily from plumbing factors, not electrical.
Onomatopoeia@lemmy.cafe 2 weeks ago
It’s because I have never seen a dishwasher in the US designed for a high current circuit.
The standard is a single dedicated 15amp circuit for the dishwasher, because the standard dishwasher is designed to use the house hot water, so doesn’t need a larger circuit.
It has fuck all to do with the water supply,
then_three_more@lemmy.world 2 weeks ago
Sounds like a legacy thing. The vast majority of houses now have combi boilers so no hot water tank. Hot water is on demand. Which would also be why separate taps have pretty much disappeared from UK homes since at least the 2010s.
Though I do think it’s very likely that a big chunk of it is as the other commenter said, an electricity thing.
With the price of gas what it is over here at the moment I’m rather glad my dishwasher is electrically heating as I can run it even on a dull day and my pannels will provide a good chunk of the power.
Rivalarrival@lemmy.today 2 weeks ago
Exactly. UK and European legacy standards required cold water dishwashers; US legacy standards called for hot water dishwashers. Once that expectation took hold, it’s somewhat difficult to alter it. Builders install plumbing for their respective systems; consumers buy appliances to match their plumbing. It’s a vicious circle with little compelling reason to break it. Neither is objectively better; neither is objectively worse.
The overwhelming majority of households had gas-fired water heaters, because for decades, it was significantly cheaper than electric, and those gas-fired systems remain in place in a majority of homes. In that sense, it’s an electric thing.
In the sense that US circuits simply can’t handle the current requirements of a permanently installed heating appliance, that is a complete myth. Trust me, we know how to
wasteuse electricity.