For heat, if your house is so inefficient as to need it, a nice wood fired rocket mass heater is the clean and efficient way to go.
BTW, building codes set a MINMUM insulation. It shouldn't be taken as a fucking standard. The waste in this society is mind boggling.
Of course, clearly you start by designing for off grid. We aren't building your grandparents summer shack here.
I am really interested in the new homestead scale pellet mills, I think Himalayan blackberry mixed with whatever waste biomass I am producing anyway would burn hot as fuck.