Had a couple hour chat with the builders today, talking about walls and floors and trusses and insulation and all that. Got shit figured out.
Gonna do single floor slab, heated by an air-to-water hydronic heat pump. R40 walls, R60 ceiling. I originally planned to do ICF but changed my mind. Doing 2x6 walls with foil faced foam on the outside.
CoP on the heat pump is gonna be ~4, using a slab qualifies me for time of day metering so I'll be heating it with 57% cost electricity. And it'll have twice the insulation as my old place, which had baseboard heat, in comparison it'll be like 1/14th the electricity to heat the place compared to that. And this house I'm in right now has thinner walls and oil heat and probably costs even more. Can't fuckin' wait.