Field data on heat pump efficiency, cold climate performance
If a boiler operates at 90% (and many don't even do that for much of the time), and the ASHP average across the year is a COP of 2.8, then that is equivalent to 280% efficiency, Therefore we need electricity to be less than 3.1 times the price of gas to break even (90% x 3.1 = 280%). If we can include a thermal store, and a cheaper night-time tariff, then in many cases you may just about break even. Solar panels will help even more. Building insulation will also be a factor in the efficiency, as better insulated buildings can operate at lower flow temperatures, which allows the heat pump to operate at higher COPs. However to do all this requires a large initial capital outlay (and the space to do it). The only way to incentivise people to invest in this kind of technology is to reform the energy market, so that non-commodity tariff costs are transferred from electricity to gas, to ensure the price difference between gas and electricity is not a barrier to decarbonisation