@matthewtoad43@YimbyEarth@CelloMomOnCars Big problem is lack of self install options. In the US it scales easily because anyone with a bit of a clue and a friend can install window air/air systems. Likewise Germany and balcony solar shows the same thing.
I am not sure the UK obsession with heating only systems glued to old radiators is going to prove sensible either - it's expensive and will lead to extra aircon being added on top as temperatures go nuts.