Aren't they just reverse aircon? I live in a hot country where most people have aircon and there's never consideration given to how well insulated the house is. I know the house where I live is not well insulated, definitely no double glazing, some gaps around the windows and doors etc. Apartments all have aircons but perhaps it would be quite hard to retrofit in the UK as here there are purpose built areas outside each apartment where the aircon units go.
I guess you do have to adjust how you live which I found quite difficult to start with. We tend to only use the aircon at night unless it is stiflingly hot but when we use the aircon during the day we will have it on in just one room and the doors all have to be shut so it doesn't leak out. It's not the norm to cool the whole house at all.
Is this how heat pumps would be expected to work? I can see that it would be a big adjustment for a lot of people and probably a step back in terms of comfort. You do get used to it though. I wonder if a combo of heat pumps and maybe something like infrared lamps/panelling would work? Like how in hot countries we have aircon to really cool the whole room and then fans to make a smaller area/your personal space more comfortable.
I'm not trying to be goady with this as I can see from the other thread that it's a really contentious issue. I'm just interested in the comparison between hot/cold countries and how we manage the temperatures.