@Sinner @SuperMoosie There are virtually no heat pumps where I live (central Edinburgh): the commonest housing style is multi-dwelling buildings, so they’d need air-source heat pumps. Add being a UNESCO World Heritage Site where we aren't even allowed to fit double-glazing or satellite TV dishes because they’d spoil the exterior appearance of the building, and, well, heat pumps are a non-starter (without significant legislative changes).