It wouldn't link, a 9kw electric shower costs 25p per ten minutes of usage, but that going by the 2018 UK average electricity price of 16p, as I keep telling Nathan the heating calculators give the best possible results.
That said I would also need to know the flow at 60degrees to compare the actual cost per litre.
You can calculate the necessary flow rate.
(Note: I was working from memory before. The heat required to raise 1L or water by 1C is 4,200 joules, not 4,400)
A 9kW heater will raise the temperature of 1L of water by 2.14C every second. So, for 55C increase, it'll take about 26 seconds. So the flow rate would have to be 2.3L per minute.
And, guess what, that would mean that to heat 2,000 litres, you'd need to run it for 870 minutes, or 87 of your ten minute units that cost 25p each, which comes to £21.75. Or, if you prefer to use my 12.5p per unit rather than your 16p, amazingly, about £17. Same as before.
The laws of physics can be
so inflexible.
Vin
PS, if you're paying 16p per unit, can I recommend
www.uswitch.com ?