RE: 12V heated car seat
Thing is, you still need some ventilation to keep demisted. the less heating you use the worse the situation gets in the future.
The lowest setting possible doesn't seem too bad on energy. It's worth setting a low temp and wrapping warm still, but I don't see wearing self-heating clothing as something to go towards. I thought about it, then thought better of it.
I'm sad that no professionals are yet doing a fit for a fuel powered heater. I don't have the confidence to do that, though we'll see next year as i don't own my Fluence yet, and I might not have it in the future.