Can I suggest going for a thicker pipe insulation, for your pumped circuit? I know its not that straighforward, but to avoid it becoming a big radiator as mentioned upthread, I think its worthwhile. I think the dreaded part L may have something to say about pumped hot water circuits, but I try to avoid studying that...
That is indeed about the most energy efficient pump you can find easily, but it might still be overkill, power wise. Not sure if they do a smaller one, but I suspect if they do, its specialist enough to escalate the price even more.
There is also the matter of the users making intelligent judgements about when to put the plug in the basin, i.e. before the water has reached the desired washing temperature, because it will soon be above the desired temp, so the cooler and the too hot water will mix to make the ideal temp. Of course this doesn't work for showers!
I bemoan the passing of hot fill washing machines, there was a theory that the initial cold draw-off negated having the water heated, but a few moments thought shows that to be false. The whole issue was not helped by the Energy Saving trust doing their comparisons between hot and cold fill machines, on a cycle that did not use hot fill anyway.... Although I have worked with the EST for around 12 years, I find much of their stuff inaccurate and amateurish, and poorly researched. Their quoted figures for the amount of water used when hand washing dishes, is utter bollocks.
