The comment I made that you quoted, about pumping cold water in, was just referring to what a mixing valve does.Richard S. wrote: ↑Sun. Sep. 10, 2023 8:57 amYou'd only want to do that if you need a larger volume of hot water. e.g you have a bunch of teenagers in the house and someone is always taking a cold shower because all the hot water was used up.
That said, these newer water heaters are super insulated and it's not going to be huge savings keeping it low. I'd concentrate on insinuation for the pipes and valves including the pressure relief valve. Install in the heated living space if possible.
Something else to consider is simply an uninsulated storage tank before the water heater in the heated space or near a heat source like your coal stove. This is effectively a passive heat pump. It may only raise the temp of the water 10 or 15 degrees and it may take years to recover the investment but it will save money long run.
Good idea about the pre uninsulated tank! If someone had the room and the spare equipment.
