cold fill washing machine - efficiency?

mutley74

We are getting a new washing machine this week which is cold fill connection only.

Our very old machine had connections for both hot and cold fill.

Please can anyone explain how a machine that is cold fill only is more efficient than a machine which uses hot water from gas boiler? maybe i am missing some poinmt but cant see how this is more efficient.

MRSTITTLEMOUSE

I've had a cold fill only for the past three years(always had a duel fill before).
I can't tell you why they're supposed to be more efficient just that it works just as well and seems quite economical so I'm happy with it although I did have reservations at first.
I'd be interested in any replies too.

Imp

If your washing machine is any distance from your boiler or hot water storage cylinder, then at the start of the wash, there will be a pipe full of cold water from you cylinder to your washing machine.

The washing machine will open its valve to fill with hot water, but it will be filled with cold water first (like running the tap before filling the basin with hot water). Hot water will enter the pipe, and some might reach washing machine. While the washing machine is doing its thing (including heating the cold water from your hot water pipe) the hot water in your hot water pipe is cooling, so for your next load you are back to step one.

So with a hot water feed, you are going to be heating some of the water twice. With a cold water feed, you will only be heating it once, hence more efficient over all.

Moss5

My machine uses hot-fill for a 90 degree wash.
All other programmes are cold fill.

CKdesigner

Imp wrote: »

If your washing machine is any distance from your boiler or hot water storage cylinder, then at the start of the wash, there will be a pipe full of cold water from you cylinder to your washing machine.

The washing machine will open its valve to fill with hot water, but it will be filled with cold water first (like running the tap before filling the basin with hot water). Hot water will enter the pipe, and some might reach washing machine. While the washing machine is doing its thing (including heating the cold water from your hot water pipe) the hot water in your hot water pipe is cooling, so for your next load you are back to step one.

So with a hot water feed, you are going to be heating some of the water twice. With a cold water feed, you will only be heating it once, hence more efficient over all.

Hi

A good explanation. Just one more thing to add. Using cold fill actually does a better job of washing as well, because detergents have several different cleaning actions that activate a different temperatures, so starting from cold makes sure all the different stages are used.

CK

mutley74

thanks for replies, suppose makes some sense, just wanted to clarify were doing the right thing when we change machines to be green!

27col

Imp has it exactly. The hot water pipe is what is known as a dead leg and will always initially introduce cold, or at best, luke warm water to the machine if it is at the end of a longish pipe run. Presumably the w/mc heater will then warm up the water to the required temperature, so there would be very little advantage to having a hot fill.