Ah, thanks, that's the post I was looking to comment on.
Just curious if you live in a really cold Climate how good do the heater work on these EV's?
The Ford setup would use a resistance heater as in the Mach-e. That's not an ideal use of battery capacity but works. Guessing it might be in the region of 5 kW.
The setup in the current Model 3/Y is more complex and interesting than any other EV that I'm aware of. It uses a heat pump of course but does not transfer heat directly to and from the environment using a condenser/evaporator, but instead uses an intermediate coolant circuit to pick and choose between the various sources and sinks available, depending on the outside ambient temperature and the needs of the motor/inverter/battery systems. This is the "octo-valve" Sandy Munro raves about but can't seem to explain properly.
There are a couple of videos on YouTube that explain the system concisely but with a moderate level of detail and focusing on below -10°C (14°F) ambient, the critical region for heat pumps.
In short, the cabin warming mostly relies on the heat pump but is minimally supplemented by a pair of "low voltage" (meaning 12V) heaters (presumably one for each side). The heat pump exploits various heat sources such as the motor/inverter/battery or conventional radiator as available over -10°C, but more intriguingly, rather than shut down if no useful heat source is available, it can also run itself in a dehumidifier mode.
That latter mode thermally short-circuits the heat pump as done in a refrigerant-type dehumidifier, using only the cabin's internal condenser and evaporator in the same cabin air flow. The net output to the cabin is confined to the power drawn by the compressor, so essentially the COP is 1 instead of 4 or 5, same as a resistive heater. But rather than shut down and defer heating to a large resistive heater it adds the
considerable bonus of "free" dehumidification. That's almost more important than just sensible heat, "sensible" as in the thermodynamic definition. I think my own Hyundai EV does this as well but still has a large PTC heater as a supplement.
Another cool feature is that it apparently can use the battery mass as thermal storage so that it can add and draw from that to pre-warm the cabin. I'm unsure though how it would know when to start this process without being privy to the driver's schedule.