Continuing the discussion on moving away from window units in the rest of my house for A/C, I have mostly come to a decision on at least general capacity if I were to switch to mini-splits.
I would do a 9k unit in each bedroom, so that's three. They don't come any smaller than 9k so that is a pretty easy decision. Master bed has an 8k window unit and it is more than adequate on even the hottest day (particularly after the insulation work) so 9k is even more headroom. Then I have also decided that I think the downstairs needs something. Yes my house is open and 3 bedrooms all cooling should theoretically cool the main floor but I don't quite buy it. I have seem the main floor get to 74F (which is totally comfortable) while the rooms with A/C are quite a bit cooler. So I think it would be better to not have the other units try to overcool their respective rooms. Therefore, I think I'd put a 12k mini-split head in the living room area, blowing toward the dining room. This would mean the kitchen kind of gets the short end of the stick both for heating and cooling from a mini-split perspective. A unit in the dining room pointed toward the kitchen might be better but has two main issues: 1) it would blow cold air at the dining room table and that would likely result in my family wanting to turn the set point up and not cooling the overall space enough just to stop the draft and 2) it would be considerable effort to run the lines on an interior wall.
Anyway, at least as far as total DIY options, I think I have it narrowed down to two:
Option 1
4 zone Mr Cool. Current 4th gen cost $4,939. Plus electrical (8 gauge, disconnect, whip) and one condenser mounting.
https://iwae.com/shop/36k-btu-21-5-seer ... 22072.html
Same inside unit placement as listed for Option 2, but with a single outside unit, placed probably where the System B describes (east wall).
Option 2
Two 2 zone Mr Cool units. $5,576 plus electrical (two runs of 12 gauge, plus two disconnects, plus two whips) and mounting two condensers.
System A would do the master bed and living room. Was thinking this unit would work. Condenser would be located basically near the front door somewhere to the right (in the mulch area, north/front side). $2,854 is the current 4th gen cost, plus electrical and condenser mounting.
https://iwae.com/shop/18k-btu-21-seer-m ... 22046.html
9k head in bedroom and 12k head in living room, but still 18k total condenser capacity. Master bed unit mounted on front wall. Living room unit probably also front wall but maybe not). I think the bedroom demand would almost always be under 9k so the downstairs unit should have access to the full 12k without issue. They do also make a 21k unit (true 9+12) but I don't think I need that.
System B would do the other two bedrooms and I would choose the 9k + 9k system for that. Condenser would be located on the east side of the house. Downstairs bedroom unit would be mounted on front wall, pointed toward door and dining room. Upstairs bedroom unit maybe mounted on east wall just to avoid having an extra set of PVC lines on the front of the house. $2,722 is the current 4th gen cost, plus electrical and condenser mounting.
https://iwae.com/shop/18k-btu-21-seer-m ... 22045.html
Splitting into two systems (with Option 2) does increase cost at least $650 and probably more. But it should simplify the installation process by not having to run everything to the same outside unit. And, I can break the project into chunks.
I think I need to continue thinking about this though and make sure I am not making a mistake with inside unit placement. At least for the living room/dining room unit, maybe it does make sense to attempt to run inside the house and pop the lines/wires back outside.