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Most appliances, such as washing machines and dishwashers typically take cold water and heat it internally. This is probably the most efficient way on a grid connected house with electric water heating.

However, I have an offgrid house, and we use LPG (a.k.a. propane) for our water heating. (Others here on Sustainable Living may use solar hot water heating or a wet-back fire etc...). We use photovoltaics for our electricity, but we have to avoid any applications that involve electric heating, as this is a very energy intensive application.

So, my question is:

a) Are modern appliances still available that take a hot water feed?

and/or

b) Can modern appliances be connected to the hot water instead of the cold (potentially with a mixer so one could choose a hot or a cold wash)?

Also, does anyone know if internal water heaters be disabled?

Henry
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    I believe most washing machines have both a hot and cold water line. Regarding dishwashers, there's an interesting discussion over here: http://diy.stackexchange.com/questions/36674/what-would-happen-if-i-connected-a-dishwasher-to-a-hot-water-supply-line – LShaver Aug 25 '16 at 01:25
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    We have a washing machine connected to a "normal" cold + hot mixing tap without problems for years. I (manually) switch it to hot water for the main washing cycle and then later on to cold for the rinsing. Of course, your energy efficiency is gone if you forget to switch back to cold - unless you have (solar) hot water in excess. – cbeleites unhappy with SX Aug 28 '16 at 18:32

2 Answers2

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I am not aware of any modern washing machines (at least in the UK) that still have a hot water feed. One reason is that modern machines don't actually use that much water, so even if you had it connected to a hot tap, it would be filled mainly with the cold water that's been standing around in your pipes, unless you have a particularly short pipe run to your boiler.

There are other reasons to be careful about simply connecting it to a hot tap - it may well confuse the electronics in modern machines, and will probably invalidate your warranty.

Once technique I have heard of to overcome this is to just pour water at 40C straight into the machine via the powder tray, and then start the machine as normal - but again this may or may not work well depending on your machine.

John M
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    We use the latter technique, despite having two inlets (in Australia), mostly because we only use the hot/warm water for the very first stage of the rise-and-hold cycle, and our machine doesn't officially support that behaviour (it's a great machine in terms of efficiency etc when we're using it, but that flaw and the 10W standby power are both annoying) – Móż Nov 30 '16 at 02:33
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The only appliances that take a water feed:

  • Washing machine. Most have both a hot and cold line connection. I've yet to see a single feed machine.
  • Dryer with steamer. Has hot water connection, with internal boost to make steam for dewrinkling/freshing.
  • Refrigerator with ice maker/ chilled water dispenser. Only have a cold water connection.
  • Dishwasher. Only has a hot water connection. Internal heater to boost temperature as needed.
Sherwood Botsford
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    Regarding washing machines I find your comment surprising. I have a fairly standard Bosch machine that we bought for on grid use and that has a single water inlet (cold). Thanks for your thoughts though. – Henry Nov 29 '16 at 20:32