'Twas brillig, and the slithy toves did gyre and gimble in the wabe

The immersion heater draws 2.86kW, and takes about 40 minutes to reheat the hot water tank after its been switched off for a day. That's 2.86 * (40 / 60) = 1.91kW of energy consumed per day.

The electric shower draws about 4kW while running on half power. Assuming a 15 minutes shower, that's 4 * (15 / 60) = 1kW of energy consumed per shower. So the shower when active consumes more energy than the immersion heater, but the immersion heater is active for longer. Hope that makes sense.

The power consumption of the immersion heater surprised me - see my next post for more.