10mm shower cable

[SUNRAY]

But an objective measurement of the performance of the old, scaled up, element deficient shower would show that it was not performing as well as the new smaller one.

I will not let this go without a final comment.
All they knew was they successfully had a shower, just as they has for a period of time without noticing the gradual reduction in performance. The next time they needed a shower it didn't work.
The new pristine unit outperformed the old petrified unit. As far as the user was concerned their perception was exactly that and quite rightly so in the circumstances.
The technical statistics has absolutely no bearing or influence on their ablutions each side of the repair, all they were interested in was the improvement.

I'm quite sure exactly the same reaction occurred the next time it was changed, presumably for a >10KW where the ignorant fitter will have extolled the virtues of the higher costs. Apologies if the latter comment does not apply.

Incidentally a trawl trough a selection of manufacturers specs certainly does indicate that all electric heaters are not equal.

In a different genre there is a lot of calculation involved with heater batteries in AHU's, whereby the thermal efficiency of different power elements and their physical size will dictate the selection used and I have worked on systems where 2 batteries of different powers are doing the same job but in different size ducts. But this is a whole different ball game.

 

[ban-all-sheds]

The new pristine unit outperformed the old petrified unit.

I'm sure it genuinely did.

Incidentally a trawl trough a selection of manufacturers specs certainly does indicate that all electric heaters are not equal.

Apart from any which they use to make light, or noise, or move air, all electric heaters use all of the energy they consume to heat whatever it is they heat.

It is simply not possible for 2 different xkW showers to produce different temperature rises for the same flow rate.

In a different genre there is a lot of calculation involved with heater batteries in AHU's, whereby the thermal efficiency of different power elements and their physical size will dictate the selection used

So if two different heater elements have, say, efficiencies of 93% and 98%, where does the 7% and 2% respectively go?

 

[SUNRAY]

I'm sure it genuinely did.


Apart from any which they use to make light, or noise, or move air, all electric heaters use all of the energy they consume to heat whatever it is they heat.

It is simply not possible for 2 different xkW showers to produce different temperature rises for the same flow rate.

Anyway this has moved away from the subject of perception which is why I posted to an old thread.



So if two different heater elements have, say, efficiencies of 93% and 98%, where does the 7% and 2% respectively go?

Sadly I am not involved in the design stage of AHU's, I'm involved with the panel build/install/commission part of the job. It is normal for a higher power heater to be used when the air velocity is higher for a given airflow rate. And I think there is something similar with water which seems to be backed up by the variations in the manufacturers specs, but I have no working knowledge of such.

 

[winston1]

So if two different heater elements have, say, efficiencies of 93% and 98%, where does the 7% and 2% respectively go?

ALL electric heaters are 100% efficient.

 

[John D v2.0]

ALL electric heaters are 100% efficient.

At doing what?
That's not a very useful metric because most people are concerned about usable heat for a specific purpose.
All gas boilers are well over 100% efficient by standard measure if you include the total of latent and sensible heat and include the heat released both indoors and outdoors.
Heat pumps would only be 100% efficient despite being more effective than an electric heater.