[fwdude]

It's not possible (at this point) for a battery to effectively operate a long-term use of A/C, much less a heater, which pull significant amounts of energy. It would be like running your home A/C or heater on a pack of batteries. Maybe for a half hour or so, but definitely not more than an hour without recharge.

Cold weather and climates also severely reduce the viability of electric cars, not just because of the climate control needs, but because the cold weather kills the charging capacity.

And I can imagine the robustness of the climate control leave more than a little something to be desired.

[chiller]

I am very skeptical too....for the reasons you detailed.

[steve86]

I believe the 12 volt battery controls the climate control circuitry but does not run the heat pump itself. It couldn’t possibly. On a Tesla Model 3 running the A/C at max continuously takes about 60 miles off the range, or 1/4.