Hello,
I’m looking at possibly installing minisplits in my home to replace the hydronic floor heat and forced air system without having to remove my slab to insulate the current floor heat system. The current forced air is the R4 (I believe) pre-insulated flexible ducts in a vented attic. I figure the minisplits could greatly increase my heating and cooling efficiency.

I plan on using 1 ducted split at 3 non-ducted units. I calculated the heat losses using the Modern Hydronic Heating book when I was originally going to try to salvage the system. I’m not sure how much this method varies from a Manual J. One of the non-ducted units will supply the unfinished basement.

The heat loss for the largest room and the connected baths and laundry/ pantry are:
heating: 21025 btu/hr
cooling: 9540 btu/hr ( I think this may be a bit low due to ~225 sq. ft of south facing windows)

Master Bed/Bath/Closet
heating: 7920 btu/hr
cooling: 4365 btu/hr

Ducted Split Loads
heating: 7433.25
cooling: 3376

Here is the floor plan, the red X’s are non-ducted and blue would be ducted and the location of the common condenser coil: