On Thu, 01 Apr 2021 10:00:07 +0100, Mike Halmarack
wrote:

snip

Thanks Tim, very informative.

You are more than welcome.

Youve certainly added to our list of
needed considerations.

I think it's one of those things that can sort of answer themselves,
when you get a feel for how much energy it takes to get water to the
temperature you need for your particular task.

I like the "back to simplicity" kettle idea.

And that (without us realising it possibly) can provide a fairly good
indicator of how much energy over what sort of time it's likely to
take any solution to get a known quantity of water up to the desired
temperature (or 'science' as it's called). ;-)

eg, Say you found you needed a whole 3kW / 2l kettle of water to make
enough washing up temperature water and that took 2 minutes to boil,
then it's likely to take any 3kW water heater around that time (likely
longer) to get that volume of water to that temperature.

Even the biggest / most powerful burner on the hob generally takes
quite a while to get 2l pot of water to the boil, especially if you
are watching it. ;-)

Cheers, T i m