Hybrid ASHP / Heat battery option: thoughts appreciated.

NedS

Fink_Nottle said:

COP of > 6? Magnificent!

Yeah, that's relatively easy this time of year. What's perhaps more relevant is the efficiency when it's -2C outside, the heat pump is running constantly and you're struggling to maintain a COP of 3.
But I hope it highlights what you have already realised, that having an old stone walled property is irrelevant to achieving good efficiency - it just means it might take more energy to heat than a well insulated property but it doesn't matter what supplies that energy - heat pump, gas boiler, oil boiler, electric heater, log burner or whatever - it's all just a source of heat. The next time someone tells you their property isn't suitable for a heat pump, you know they have fundamentally not understood heat pumps (or the concept of heating a property).