Reasonably conventional HVAC options

[hikerjohnson]

Hey folks, I've been here for a long time, not much in the way of posting, but a real fan of heat pumps. Put a single head mini-split (Mitsubishi Hyper-Heat) in my downstairs (open concept Cape Cod) a few years ago and absolutely love it. Takes care of the shoulder season heating before the woodstove kicks in full time, and does a great job of cooling the downstairs.

Trouble is, cold air doesn't rise. So, when the dog days of summer arrive, the upstairs (3 bedrooms, hall, and bathroom) absolutely roasts. In winter, life is good, as heat rises, and convection handles the upstairs pretty well.

I have wracked my brain for several years trying to figure out how to efficiently get a heat pump to handle the upstairs. It's just me and my wife, so the majority of the time, the two spare bedrooms are closed to reduce HVAC loads, but I'd like to incorporate them into a complete solution.

So, the issue is, I have no duct chases. The house was built with electric baseboard (ugh.) I am reluctant to put a wall-hung mini-split head in each room, as some of the rooms are quite small. The entire heating/cooling load of the upstairs is 9500/5500 Btu/hr, respectively. Thats basically one head for the whole upstairs.

Any ideas besides hang one head and leave all the doors open? I've considered multi-heads, ceiling-mounted, ducted units in the attic (again, ugh.), etc. They all seem lacking for such a small heat load.

I did do an ACCA Manual J calculation, and since that time, I've replaced all the windows and doors, and re-sheathed the house with new house wrapping, so the thermal performance has only gotten better.

Appealing to the crowd for options I may not have considered. What do you think, group?