• Mr_Blott@lemmy.world
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    1 year ago

    It’s because our dishwashers are massively more efficient and environmentally friendly.

    They use very little water, which they heat up themselves to save energy

    The only drawback is they take longer to clean the dishes, up to three hours

    But nobody would be so selfish as to demand their dishes be done quickly over preserving our environment, would they?

    • Nollij@sopuli.xyz
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      1 year ago

      Why would that save energy? It’s going to be resistive heat, which at best matches the water heater. Some models in the US include a heating element, but it’s more of a convenience. The vast majority are simply connected to the hot water line, since that’s why it’s there.

      Also, let’s talk numbers. From what I could Google, EU dishwashers use 1-1.5KWh/load, while US dishwashers use an average of 1.15KWh/load. Certainly there are more efficient models, but this shows that there isn’t a significant difference in energy usage between them.

      • orrk@lemmy.world
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        1 year ago

        your energy calculations are forgetting the energy cost of the pre-heated water, it’s the appliance equivalent of an offshore tax haven!

      • Mr_Blott@lemmy.world
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        1 year ago

        Your system - Add cold water to water heater and heat (using energy). Keep at required heat until needed, could be a whole day or more (using energy). Pump hot water through cold pipes to dishwasher, losing energy. Reheat (using energy)

        Our system - add cold water to device directly. Heat (using energy)

        I couldn’t explain it any clearer so I’ll fuck off now

    • Squizzy@lemmy.world
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      1 year ago

      I’m confused, our as in European dishwashers are more efficient and environmentally friendly?

      But wouldn’t it be even more so if the hot water that was stored and not being used was the feed instead of cold water? That was the temperature increase is minimal and a lot more efficient.

      The eco wash is the best wash on my dishwasher.

      • Rivalarrival@lemmy.today
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        1 year ago

        It has nothing to do with energy efficiency, and everything to do with UK plumbing. A building’s hot water system is presumed to be subject to environmental contamination, and not considered potable. Only the cold water supply is considered potable.

        It’s the same reason why they have separate taps for hot and cold water, while the US uses mixing taps almost everywhere.

      • Mr_Blott@lemmy.world
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        1 year ago

        The majority of our hot water is on-demand so no. Also, is it more efficient to heat the water, pump it through a potentially cold pipe, only to have to reheat it again? Nope,just heat it where you need it, and with a lower wattage heater

          • orrk@lemmy.world
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            1 year ago

            everyone, ever. unless you are running some industrial operations that require constant hot water, there is no reason for even a large family to be using water continuously, and hot at that

        • Rodeo@lemmy.ca
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          1 year ago

          Heating a volume of water a given number of degrees takes the same amount of energy regardless. Using a lower wattage heater is just going to make it take longer, not save any power.

          • Mr_Blott@lemmy.world
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            1 year ago

            Edit to explain in detail -

            Your system - Add cold water to water heater and heat (using energy). Keep at required heat until needed, could be a whole day or more (using energy). Pump hot water through cold pipes to dishwasher, losing energy. Reheat (using energy)

            Our system - add cold water to device directly. Heat (using energy)

            No idea how Americans can’t understand that most of the developed world is decades ahead of them environmentally 😂

            • Rodeo@lemmy.ca
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              1 year ago

              I understand the difference, I was pointing out the wattage thing doesn’t really make sense.

            • Rivalarrival@lemmy.today
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              1 year ago

              Using gas to heat water is considerably cheaper than using resistive electric. Especially when the electric was historically provided by coal or gas anyway.

              Burning gas to heat water into steam to turn a turbine to turn a generator to pump electricity to a resistive element inside a dishwasher is not nearly as efficient as just burning the gas inside a water heater and sending it to the dishwasher. The heat losses incurred while passing the water from a gas heater to the dishwasher are a tiny fraction of the losses incurred in the convoluted processes involved in traditional electrical generation.

    • Rivalarrival@lemmy.today
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      1 year ago

      No.

      The reason your dishwashers use cold water is because your hot water supply is not presumed to be potable water.

      EU regulations allows for gravity-fed hot water tanks in certain jurisdictions, open to atmospheric pressure, and thus possible contamination. They did this to prevent the possibility of exploding boilers.

      Since the building’s hot water supply is presumed unsafe, dishwashers are required to use the safe, cold water supply to generate their own safe, hot water.

      US regulations do not allow hot water to be held at atmospheric pressure. We use T&P valves to limit boiler pressures and prevent explosions. Our hot water is not exposed to environmental contaminants, and is presumed potable.

    • theragu40@lemmy.world
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      1 year ago

      I’m so confused. Whose dishwashers are you talking about? I’m in the US, you’re describing every dishwasher I’ve ever had, except that we always hook it up to the hot water line. Our unit takes very little water, it takes hours to run a load due to efficiency features. It has a heating element inside to take whatever water it gets and keep it hot for the cycle.

      I don’t really see why it’s any less efficient to use the hot water we are already heating with our water heater (which heats much more efficiently than a small electric heater would). The water originally arrives to my house cold, it has to be heated one way or another. My dishwasher is less than 10 feet away from my water heater, water is not losing appreciable heat on the way to the dishwasher.