OK - someone said I had lost interest in the thread. Nope. I'm just not willing to debate the often ill informed comments that have been posted along with the insightful ones.
Only Sean and spinlondon apparently have any real experience of this type of build. Other than the eminently sensible electrical design advice that has been given which I have already said is making me seriously consider changing the rating of the water heaters, 80% of the posts are just argumentative and "you don't want to do it like that". I said I didn't want to debate the design scenario, but there appears to be a lot of interest (or maybe not).
I understand the reasons why folks don't know or haven't considered alternative build or design scenarios. I also understand the uselessness of many of the alternatives that are out there which are only really useful in two cases.
1) Where the environment is harsh and requires it
2) Where the technologies are being fitted as part of a refurb rather than a new build.
Where we live the average winter temperature doesn't fall below 3.7° -
Plymouth, England Climate Plymouth, England Temperatures Plymouth, England Weather Averages
As a result, high levels of insulation and air tightness coupled with an efficient MVHR should mean no heating is required over that generated naturally within the home.
These things are calculated properly and scientifically and do not require opinion. If top up heating does prove a requirement, I think you'd agree that adding a 1.5kw panel heater somewhere shouldn't prove too challenging!!!
As it is my home,
my opinion on the quantity and frequency of hot water that will be required is such that showering and hand washing are all that should take place. We wash our clothes in a washing machine. We wash our dishes in a dishwasher. What you might do is a matter for you.
We are trying to build a 21st century home - not an 19th century one. We are using state of the art knowledge and techniques. Only one other home has been built in the UK to date using the build method we are using. That was the proof of concept in Scotland. Ours will be the first commercially built home after that.
I have also effectively been called a liar - the first time it was reasonable and put in a polite way and I understood and answered it.
After that it is just offensive.
In short, while you guys unquestionably know more about electrical science than I. I am not going to take lessons in the overall design concept or in day to day living paradigms from you, thanks very much.
Finally, again my genuine appreciation to the posters who have helped with their constructive suggestions and observations.