They both have a lot of experience with these units; in fact, Olle used to work for a company that sold them. They told me the placement of a heat pump was very important. I had intended to put it on the kitchen wall, as my little sketch shows:
The problem with installing it here is that airflow (as indicated by my red arrows) can only reach the central area. I can't direct air into the bathroom or either bedroom, so only part of the house benefits directly.
Peter said the idea setup would be to put it in the center of the house:
Although it would be most efficient for air circulation, it's not possible, as that wall of the house is all glass, so there's no place to mount the fan unit.
The third option would be to mount it on the opposite wall:
That gets air most everywhere, except, perhaps, the guest bedroom. However, one big drawback of doing this is what happens outside. That wall is the front of the house. I'd have to attach a decent- sized pipe along the front of the house down through the deck to the fan unit below. That would be unsightly, at best. Also, having the fan unit beneath the house at the front makes it visible from our new deck.
I'd have none of these problems with my original installation idea. The back of the house is not visible or trafficked. The fan unit could be installed safely and quietly out of the way. We would lose some of the whole-house efficiency of a front-wall installation, but it would look a lot cleaner.
The advice from Olle and Peter is excellent, but I wonder if I really need to worry about heating the whole house. We can heat our bedroom pretty easily with a small radiator, a nice comforter, and perhaps a bit of cuddling.
I will give this a bit more thought on these winter days. It is very good to have valuable input from my neighbors!