Preheating for 2-4 minutes makes the car much more tolerable, while losing only about 3-4% net charge if plugged into level one. I did that for 5 years, with the car parked out in the cold, and it worked fine. I'd activate the climate control right before getting my coat and gloves on. a ~45F interior and warm seat and steering wheel beat the hell out of a frigid car.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.