Hello! I would really appreciate any insight you could give me on my plans. Currently in a late 70s split level home, roughly 1500 sq feet. There's window air but almost never have to use it. This year we added a steel roof and insulated attic to R-50. Old original leaky windows still in place but no plans to update yet. The house has 11,000 watts of baseboard heating, 4 baseboards upstairs and down 4 downstairs. We do not heat the downstairs due to cost and typically run on 3-4 heaters upstairs during the winter. Below is a load calc that was performed. My end goal would be to have one split that would do the entire house. Due to being a split level that's more than likely not a possibility. Activity downstairs is minimal. Would it be possible to run the first floor completely off of a 12K unit? I was thinking a Gree Sapphire as it will run down to -22 and has an HSPF of 14 and heating is my primary goal. I would set the head down the main hallway to blow warm air across the hallway upstairs. All doors are always open upstairs. See layout (Black line indicates hallway)

Cooling/Heating load

1 story in Texas, 1550 sq ft, metal building shell with closed/open cell. I have an 18k floor/ceiling from pioneer on ceiling. Mounted at end of hallway. Will cool and heat house with fans moving air around.