Electric shower available as 9.5kW or 10.8kW

I’ve seen Triton showers in places - eg when we used to rent cottages for holidays - and they were okay. I don’t know what power they were and we tended to have our holidays in the summer.

Don’t Combis heat water at mains pressure? If so, you wouldn’t generally use a pump.

Power / pump showers tend to be used when you have a hot and cold tank and a limited ‘head’. Our family bathroom shower would probably be ok without the pump / power shower but we decided not to risk it- the old one could be a bit hit and miss. The en-suite certainly wouldn’t and had the Mira before we had the re done.

The plumber had to run new feeds to the new power showers - from the hot and cold tanks.

Thats right. But combis are just as limited in peak output as an electric shwoer is, unless you go to Germany...where my sister had in her 'proper German built house' in addition to 6-9" of polystyrene everywhere it touched the ground, i a 45kW combi with a 4000 litre oil tank.

In the basement.

But unlike here, that was not the cheap option. There was UFH in every room as well I think.

The whole thing was built out of concrete. Very WWII. But rendered with stucco to make it look Tyrolean...

Yes, Never use a pump with mains pressure feeds

Are they immobile?

I know they have that reputation, but...

Yes.

But... so what?

So what??

You asked a question above, and there's your answer.

I was well aware of how many watts equal one HP (though ISTR a slightly different, but very similar, figure).

But you never see an electric fire marked with its output in horsepower!

If you say so.

But there's a direct correlation, and electric motors frequently are, so your question - 'HP for measuring the output of an non-motive electrical system?', made no sense.

You didn't say 'stating' the output, you said 'measuring'.

Windmills don't run around the country either.

It's perfectly possible to have an oven rated in horsepower.

Or a windmill. Its just that electricity came after steam engines and horses.

So we use watts exclusively

One necessarily precedes the other, as I'm sure you'll agree.

....or 1 hp = 550 foot pounds per second.

I don't think hp has any meaning these days. bhp is what you mean

Maybe they should be rated in the time taken to toast a sourdough crumpet ?

Cubic lace holes per parsec is always a good standby unit.

The Spanish horses had a siesta?