The thing that mystifies me is the cost of an air source heat pump (just the units, not the installation costs). They seem to be anything from £5K-£10K even for a modest power output. What do they have in them? A combi-boiler costs in the region of £1K and that has loads of plumbing, valves, sensors, control boards etc in it. A basic fridge is a few hundred quid. And a heat pump is basically just a scaled up fridge crossed with a combi-boiler.
