Quote:
you'll be running heated water through several meters of uninsulated piping

What makes you think my piping is uninsulated?

Sure, it's not as insulated as the tank, and there's obviously a greater surface area to volume ratio in the pipes, but, here in the South, plumbing is traditionally run in unheated areas and has to be insulated to prevent freezing for the few days where that's possible.
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Bitt Faulk