Comment by PunchyHamster

> I've always wondered why we don't build homes with a buried tank of water used as heat storage. In the summer it can be heated with solar thermal to around 90c, and in the winter heat can be drawn out and go through radiators or underfloor heating, with a mixer valve. You just need a few pumps and valves, not even a heat pump is needed.

Because building houses is already expensive, and that would add significant amount, pushing it into "can't afford it in the first place". And zero ability to realistically service it means anything going wrong might make whole investment moot.

On top of that, any investment like that competes with "why not just put the money into low risk fund"

> 1800kWh per year

now factor in losses for months now factor the fact the energy you're using for heating is one you're not using for... energy or selling

also is that heat or energy ? Because if that's "what power heat pump used", multiply that by 3-4

It's just... expensive to do it like this. Expensive enough that most people that could did the math and it wasn't mathing