Been there done that. I've driven in the cold temps. First 2 weeks here of January were in the range of +10 to -8F. My wife and I drove a few times with no heat in single digits or teens at best. We just dressed in layers, heated seats and made it without heat or defrost.
If you turn on the heat (I tested this today), you're adding an average of 20 amps load on the battery. Its like driving around with 1 extra bar or power. So if you're at 1 bar with your foot, with heat the draw is 2 bars. If you're at 2 bars going uphill, its really 3 bars. That's over 100 amps and stressful on your battery. If you want to use heat, start the engine to assist. Electric heat is OK if its not so cold out, but when colder its alot on the battery and if too cold (single digits) then the engine is starting anyways as 30 amps from battery heat is still not enough.
So yes, I've survived it all. My record is -7 to -10F early morning driving around with no heat. The windshield started to ice on the inside on the bottom and 15 minutes into the trip even in EV Now the ICE started to do something, not sure what, assist the battery I suppose, but the heat wasn't even on. It warmed up some then shut off, 10 minutes later it did it again for another 2 minutes or so and that was it. On the way home 3 hours later it was 17F and no engine start and it felt so "easy" compared to -7F. That, I have to admit, was brutal. A heated steering wheel would have been great, the gloves were not enough I should have used mittens instead.
But due to the lack of heated steering wheel, and that's not going to happen, consider heated gloves for around $70 or less, google them you will see. Might be a good choice for you guys. Also, if I need to access the touch screen, I take my glove off for a few seconds, do what I need, and put the glove back on. Its not a huge issue...
At the end of the day, I prefer to use the battery to propel the car forwards, not waste it on heat. Other minds will vary... Even with that in mind, you can still use shore power to warm up the car. We went to the movies on Tuesday and the car was plugged in and charging. During the movie I programmed go times to warm up the car to 72F so when we got out we were able to step into a warm car. It was 68F inside and by the time we drove 9 miles home the internal temp had dropped about 10 degrees. Not bad, that was a good benefit of shore power.
Edited by rbort, 18 January 2018 - 12:28 PM.