"Owain" wrote in message
...
JustMe wrote:
"The Natural Philosopher" wrote
Yes. Scrap the combi and put in a mains pressure DHW system. If mains
pressure is good enough, that will do what you want.
I looked this up on Google. I'm not happy replacing my combi and
spending
cash (plus getting builders installing bulky stuff and new pipes) to
replace
what otherwise works fine for me - which is what this appears to entail.
It's *just* my shower that I'm looking to supercharge.
I don't need to improve flow rate for running cold taps, hot taps at
sink
etc, as these are quite good. I just want a high-quality power shower
solution.

Yes, but the energy requirement of a shower is the product of volume of
water * temperature rise.

If you want *lots* of *hot* water you have to put in lots of energy.

The amount of energy off a domestic electric shower is limited to 10kW.
The amount of energy off a combi boiler is limited firstly by the
boiler, but as even small combis are usually 30kW + that's a significant
improvement on an electric shower, and then by the gas supply to your
house. If you want a really big combi you might have to upgrade to a
commercial gas supply.

A good combi on a domestic gas supply will provide a standard shower
acceptable to most people. However, if you want full-body jets and that
sort of thing, you need more energy input than a combi can provide
instantaneously.

So, if you want more hot water than your available source of energy can
provide instantaneously, you have to heat the water in advance over a
period of time and then store it. This is why a 3kW immersion heater on
a cylinder can give a better shower than a combi boiler of 10x the power
- although obviously only until the stored water runs out, then it's a
wait of maybe several hours for the store to heat up again.

Owain

OK, I'm getting my head round this now - thanks for explaining in a manner I
can understand. I'm pretty sure that the cylinder route is one that I don't
want to follow, and have taken your advise, above.

Thanks again.