Hi Furoner,
I have limited knowledge of ASHP but cn tell you they are basically an air conditioning unit that can produce heat or cool air, which is probably the same as the heat/air conditioning you find in hotel rooms etc.
They cen be up to 400% efficient in heating mode, i.e. 1kw of power in and 400kw of power out.
We are in the process of buying an aprtment that will require heat/air conditioning and this is the type of unt that I will be having installed.
No idea on costs to buy and install but perhaps someone else can provide some guidance on this.
Kelju