Here's more details of my daily usage
Parked outside for 8 hours
Drive another 120km home.
I know it's not ideal, but what's the best scenario, during cold winter.
I need to do 240km (150mi) highway trip on weekday. Trying to plan for the worst days (-30 in canada)
A car that is rated 402km, i was expecting to be able to do 240km, especially if the car is pre-heated at home...Honestly, you bought the wrong car. I would look to replace it with a LR version. If that's not an option, I would SC on your commute to or from work. Don't charge to 100% daily; charge to 90% and preheat (really hot) prior to leaving.
I agree that in less than an hour, or even less, any part of the car will be at ambient external temperature.For 8 hours trying to "insulate" with a car cover will accomplish nothing,
might actually hurt interior temps due to no solar gain.
I say this as someone who has driven my S in -30c.