Andy Hall wrote
Martin Angove wrote:

3) Modern dishwashers use very little water , so much of what will
come from a DHW cylinder will be the contents of the pipes and cold
anyway. Since the water volume is smaller than it used to be,
electricity consumtion is reduced anyway.

I always run the hot tap through to hot before I turn on the washing
machine. Unless the first thing it does is a cold fill (which I don't
think it does) I should save 0.01p per year using this method ;-)

Cheers,

Paul.