Few domestic buildings in the UK have the space to install the huge and noisy air conditioning fan required, never mind the insulated piping to get the heat into the house.

It's a nice idea, but the reality is that most people will end up heating their water with a good old immersion heater.

See https://youtu.be/GhAKMAcmJFg

The real problem is our buildings are badly built and insulated - and the new ones just aren't good enough.