Very cool. I hope to build a ground-up home someday, and have thought about using extra thick walls as you did. How much, percentagewise, do you think that construction technique cost you?
I know, for example, that ICF forms are not inexpensive, plus the added cost of thicker concrete pours. And, of course, all the extra 2x4s (somewhat mitigated by the fact that I'd NEVER use single-thickness 2x4 walls, opting for 2x6 studs minimum instead). But so few homes are built to this sort of standard here in SE Wisconsin (which defies logic!) that it's hard to gauge just how much more it's going to cost, short of designing a home and getting quotes.
Your Volt fits right in there, doesn't it? :-)
Nice videos. I do wish I were young enough to start from scratch on such a passive house but, like others, the best I can hope for is some retro fitting. Glad to see we both chose to buy a Volt.