Something that crossed my mind is, what is the current state of art most efficient heating technology available as of today? I guess cabin heating wouldn't matter much to those in warmer regions but it is quite important to some of us. In the case of Tesla, we can pre-heat while plugged-in but surely, maintaining that temperature when outside is cold could easily become quite a power drain. Also, the battery pack performs best at a higher optimal temperature so surely, it could benefit the whole thermal management system to be designed like home central heating systems such that there is a single point efficient heat source and heated water or oil is carried around vital components of the car including cabin. Or is that an overkill for Model 3 ?