GaslessInSeattle said:
the car is designed to be used with the prewarming function in the winter time and greater reliance on the seat and steering wheel heating if you have it. don't be afraid to set the prewarming function for a half hour or more before you drive. you can eliminate your climate control heater use with an extensive prewarm and substantially improve your range over the numbers on the charts. I'm getting close to what I got in the summer time relying on prewarming, 80 miles without dipping into VLB territory.
It really depends on your prewarm and the distance to drive. I found that I would prewarm and not turn on the heater until I got really cold again (this was when the temps dipped into the 20's), which happend pretty quickly on my commute. The downside to his method if you have a long haul, the liquid that is heated up as part of the heater system cools down completely and has to be reheated back up. If you leave the heater on from the start, it only has to maintain the temperature of the liquid, saving energy use.
Short distance, just preheat and go without heater, longer hauls I found i used a decent less not letting the liquid in the heater cool back down again. If you can survive with the preheat all the way to work, it saves alot, if you need to turn the heater back on again, its best to keep it on from the start.