I am not all that sure I want it IN my house, and the garage for many homes is in the house. Yeah I know, people garage their cars but this is wholly different. Maybe outside the back in a small enclosed space, similar to an AC unit
I will be curious as to regulations for ventilation, wiring, and similar, are.
I think operating temperature is important, so I'd imagine outside or garage is a no go? (My garage gets down to 40F at night, not sure if that's typical).
But maybe with enough insulation you could put it anywhere?
Tesla cars are popular in northern European countries and I imagine these will work along the same lines: active heating of the battery. In the cars the capacity sacrifice is minimal and I imagine stationary batteries will be even better as (like you say) you can wrap them in a ton of insulation without having to worry too much about bulk and weight.
I will be curious as to regulations for ventilation, wiring, and similar, are.