I can see where it would be misunderstood. It talks about "temperature" and 'subtracting 1% for each 4F below 70F' but this is just about reduced battery performance, not heater usage. You also have to subtract 1.5kwh for heat for each hour driven. Had I known this hadn't been covered more thoroughly I would have tried to contribute.
Here's another anecdotal metric. The first Winter I drove my 2013 I was still working, and had a 42 mile round trip commute. The trip in was in the late evening, the trip home near but before dawn. Most of it was secondary roads and lower speed (40-45MPH) highway, but there was also some ( several miles) highway driving at 55MPH. Based on what I know now, my pack probably had ~95% remaining capacity - maybe a little less, as it was a Hot Summer and I didn't know about heat-related degradation. Anyway, I took fairly stiff measures on Frigid nights like that, at least by my standards, using a 12 volt heated fleece car blanket over my lap and legs while driving, accelerating slowly, never exceeding 55MPH. I set the heat to 69F, IIRC (I have health issues) and the blower on 1 or 2. I didn't know about partial recirculate then, so I switched Recirc back and forth to save heat and minimize fogging.
On the coldest commute it was in the Teens on the trip in, and fairly windy. The trip home was at about -5F, with stiff winds. I chickened out a bit and stopped for a 10 minute partial charge at a Nissan dealership. I noted how much charge was added. When I got home I had about 8 miles of indicated range left (I don't think the GOM blanked), having added about 6 miles of range at the dealership. So on that blustery, frigid night, my car had a range of 44 miles, with no real highway driving and less than adequate heat. I'd estimate a mostly highway trip at 55MPH would have yielded a range of about 35 miles under those conditions. Maybe less.
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.