We’re in the process of gathering some estimates for a slim-ducted mini split for our 2nd floor, and we’re hoping to get some opinions on whether a low- or medium-static slim-ducted mini split is a better bet.

The second floor consists of two bedrooms (one at 170 sq ft, and the other at about 200 sq ft), a bathroom, and a small hallway. (Floor plan attached.) 

I’ve run several room-by-room Manual Js (using CoolCalc and hvac.betterbuiltnw), as well as a block load, and the heating load comes out anywhere between 8-9k for the upstairs, with a cooling load at around 6k. The two bedrooms each land at around 3k for heating and 2k for cooling.

The air handler will be going in the closet that shares wall space with both the master BR and our kid’s room, as well as the hallway, so our expectation is that we would be able to do some very short duct runs, especially as we push back against some contractors who are insisting the air supplies should be on the exterior walls near the windows. We may end up running a supply to the bathroom as well. In terms of duct location, because of some low ceilings (about 7’4″), it seems like the ducts may need to go in the unconditioned (though insulated) attic. Likely insulated flex duct, with those buried in the cellulose insulation we have in attic.

In the above scenario, would a low-static 9k unit meet our needs? Or does the fact that we may want to supply 3 rooms require going up to a medium-static unit, the smallest of which is 12k? In looking at the NEEP site for the medium-static equipment recommended to us (Mitsubishi APEADA0121AA70A and Fujitsu ARUH12LUAS), those units look to be ridiculously oversized for our second floor heating/cooling loads.

Thanks for any help/opinions!