Thank you for all your replies, I should have added it is unlikely if ever it would be used for aircon as we don't need that here in the UK except for a way of wasting fuel and polluting the atmosphere in cars
I seem to remember there is not much chance of a straight swap for a boiler as the hot water flow temperature has to be low to maintain anything like a reasonable COP so either you have to go for underfloor heating or vastly oversized radiators. That is why I am considering air to air.
I am interested in supplying 1.5Kw to an ASHP in winter from PV, may I ask what sized PV system is that, 10Kw+ ?
These websites (Daikin & Panasonic) are a bit of a nightmare to navigate and I have yet to find COP charts for any product on either of them
Apparently I heard somewhere they are even more sensative to external humidity than temperature (in heating mode). I see there are various convelutions of COP on data sheets now presumably invented to obscure the truth so definetly a case of tread very carefully and spend plenty of time investigating methinks.
I have no doubt they are very competative with electric heating BUT I feel ASHP is going to have a tough time competing with my elderly oil boiler
Typical winter temperatures here are -10C or colder for days at a time, -5C for weeks at a time and below zero for a couple of months and of course thats when the maximium heating power is required.
Back to trying to find real information in websites vs marketing bs!!