In the blogs section the is a nice write up for driving MS in cold weather. I have one question. Why would preheating diminish lifespan if not plugged in? "If you're not plugged in then it's a different story. You could end up using quite a bit of battery power preheating. This is not just running your battery down; it's also using up a little bit of your battery's lifetime. My usual compromise is to prewarm the car for 10 minutes to make the cabin reasonably comfy, then off I go."