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[I_want_an_Omega]

Many domestic appliances these days only have a cold water fill facility. I know this has always been true of dishwashers - but many washing machines these days only have the option for cold water fill.

So, on the basis that the the machines heat the cold water using electricity upto their operating temp - what's to stop using hot water into the cold water feed? The thermostat will cutoff earlier thus saving electricity. If the hot water used is heated by gas then the cost of heating that water will be less and the cycle will be quicker - wont it?

I know there is probably a reason/reasons not to do this - but can anyone think of good/solid one?

[mantahatch]

Was thinking about this the other day. As I have both a hot and cold feed under the sink would only take 2 minutes to swap over.
Would be interesting to hearthe experts opinion on this one.
Someone did tellme that it depends on the distance from the hot water tank as many new machines use so little water that the hot water won't get to the machine. And secondly they said something about the rinse cycle but can't remember what. Maybe they ues coldfor rinsing and if hot water comes through would that give a sensor a faulty reading ?

[Kevin Wood]

Well, your washing machine will be using warm water in the rinse cycles too, which may cause issues, and is a little wasteful. The other issue is that I know in our house, you'd get very little in the way of hot water before the machine was full due to the length of the pipe run.

I expect the main reason manufacturers are only fitting one feed is to reduce costs!

[Kevin Wood]

Also - bear in mind most UK hot water feeds are gravity fed from a header tank. The pressure might not be great enough for an appliance designed for mains water.

[aaronjb]

Well, your washing machine will be using warm water in the rinse cycles too, which may cause issues, and is a little wasteful. The other issue is that I know in our house, you'd get very little in the way of hot water before the machine was full due to the length of the pipe run.

And if you did, you'd never be able to do anything less than a 60-80ºC wash (depending on water temperature).. which might mean nothing to the manly men among us, but suffice to say you might find all your shirts come out the right size for a child

I'm sure I read somewhere that the switch to cold-only fill was because the manufacturers weren't able to A-rate the machines unless they could quantify how much energy would be used heating water; and of course they can only do that if they're the ones making the thing that heats the water...

[I_want_an_Omega]

If you "ran off" the not quite so hot water before washing then that would be wasteful & also zap hot water into the machine which could upset clothes on a 30 or 40c wash.

How about the dishwasher though?

[cleggy]

I wouldn't worry about it, we won't be using appliances once they get chipped to turn off when the demand for power gets above what the useless wind turbines can produce

So it's back to the Copper and  Posser with a Mangle, washing up in the sink, and cold storage will be the stone slab in the pantry

As for water ..... dig a well

[Kevin Wood]

I'm sure I read somewhere that the switch to cold-only fill was because the manufacturers weren't able to A-rate the machines unless they could quantify how much energy would be used heating water; and of course they can only do that if they're the ones making the thing that heats the water...

That sounds about right... Making things less efficient in practice to keep the yoghurt knitters happy.

[Kevin Wood]

How about the dishwasher though?

We have just bought a new dishwasher and the manual encourages connection to hot water when it's heated by gas / solar.

I still wonder if there's enough pressure, though. Maybe I'll try it. Our hot water in the kitchen is softened, so that's another advantage.

[steve6367]

It would make your min wash temperature 60C (temp of incoming hot water) - so less efficient that heating the cold water to 30C with electricity.

Steve

[I_want_an_Omega]

It would make your min wash temperature 60C (temp of incoming hot water) - so less efficient that heating the cold water to 30C with electricity.
Steve

For a washing machine then yes, I can see the logic of that. But dishwashers dont have a similar cool wash (do they) and always seem "hot" to me at the end of the cycle.

Unless that hot water has been heated by PV Solar and would otherwise be sent back to the grid. I don't want to get into that whole debate here (please) as many on here regard solar as the domain of "retards". 

[I_want_an_Omega]

How about the dishwasher though?

We have just bought a new dishwasher and the manual encourages connection to hot water when it's heated by gas / solar.

I still wonder if there's enough pressure, though. Maybe I'll try it. Our hot water in the kitchen is softened, so that's another advantage.

That's interesting - what make?

[Marks DTM Calib]

It would make your min wash temperature 60C (temp of incoming hot water) - so less efficient that heating the cold water to 30C with electricity.
Steve

For a washing machine then yes, I can see the logic of that. But dishwashers dont have a similar cool wash (do they) and always seem "hot" to me at the end of the cycle.

Unless that hot water has been heated by PV Solar and would otherwise be sent back to the grid. I don't want to get into that whole debate here (please) as many on here regard solar as the domain of "retards". 

It is 

The old be seen to be doing rather than actualy doing (government/EU policy)

[Kevin Wood]

I remember reading somewhere that biological washing powder has enzymes that are more active at low temperatures and killed off at higher temperatures, hence for them it is important that the wash starts out cool-ish and is warmed in the machine.

Right. I'm going to stop now as I'm starting to sound like a washing anorak when in reality it's a "pink job".

[05omegav6]

  how it works and fixing it when it breaks are definitely not pink jobs (unless TB is volunteering )