Use an HVAC heat pump for heat and cooling for improved range, especially in cold weather. The Heat pump is more efficient than a resistive heater currently used.
It is wasteful to use electric resistance heat when the same electricity put into a heat pump can move about four times as much heat into the car. Electric energy is much more valuable than combustion energy, as we know from the fact that electric motors are several times more efficient than combustion engines. For the very same reason that EVs are a great idea, the use of electric energy to resistively heat them is a terrible idea.
Reversible heat pumps are standard practice in home HVAC systems and now offered in some EVs, such as the current generation Nissan Leaf.
Heat Pumps will add cost, and it should be pointed out that a resistive heater is still required, as heat pumps efficiency drops as the temperature gets colder, and stop working at about 0 degrees F. Tesla does take waste heat from the battery and motor operation to help heat the cabin.
Tesla now uses a heat-pump design on all its cars. The Model S and X switched to a heat pump design with the mid-2021 design.
If you dig deep, you'll find the heat pump is used only for cooling, and all heating is done using simple resistance heating. I flund the patent on the HVAC system to be the most definitive documentation I could find, but you can also verify by listening that the compressor does not run when heating...
The "light editing" of this item misrepresents the cost, which will be close to negligible, since a heat pump and all required heat exchangers are already present in the existing system. All that is required is a reversing valve for the coolant flow and additional software to control it.