"Christian McArdle" wrote in message
et...
(i.e. it will never run out even if you showered 24 hours a day).

Just noticed your comment about a 18lpm shower. This would eventually run
out. However, a bog standard 28kW system boiler and a 180L heat bank, like
mine, would be capable of running this shower for 40 minutes before
running
out. In this time, it will have heated 720 litres of water to 40C, which
is
about the equivalent of 6 baths. If you actually ran such a shower for
such
a period on a regular basis, I'll personally nominate you for a "fat arsed
american" environmental damage award. I'm not actually suggesting that you
intend to, mind, just that such a storage solution would easily meet any
sane needs for a domestic property. i.e. a 5 or 10 minute 18lpm shower
won't
trouble it at all. OTOH, even the largest genuinely instantaneous combis
with no storage would struggle with a 18lpm body jet shower. You certainly
couldn't turn on a tap elsewhere without problems.

That is 18 litres/min "mixed" hot and cold. Some can cope OK and even have
the odd tap turned on and not affect the performance.