Heating when the power is off.

[Joe]

Additionally a lot of people run this tank at a low temperature (50 deg C) in order to save energy but this tank can be increased all the way up to boiling point. I should add this can be pretty dangerous due to steam or water hammer effects but you can safely run around 70-80 deg C and this will provide a far higher heat storage.
Slightly off topic but don’t run the tank too low as you can breed very dangerous bacteria. In fact this will be a hazard in the future when they introduce air pumps etc.