Re: Hot water...
"Those "instant boiling water" taps are convenient but also bloody wasteful, continually keeping water up to temperature in the off chance that you are in and want a cup of tea."
No, they do not.
That's the idea... no power gets used until you attempt to get hot water, which is heated as it flows through the device.
No energy is wasted by avoiding creating any hot water that is not being drawn from the system.