At low temps COP is lower, meaning you'll not get 4 units of heat for 1 unit of energy spent, but COP is still higher than 1 meaning using heat pump is still cheaper than using basic electric resistive heating.
I think Northern England climate is ideal for heat pumps -- it never gets too cold, never gets too hot.
I think Northern England climate is ideal for heat pumps -- it never gets too cold, never gets too hot.