Hey Everyone, In trying to keep my thoughts and your read organized, I broke it down into sections. Thanks for your help! BEFORE I got my brand new Model X 100D in early September. Except for minor trim issues that I decided to leave be, it was the car my wife and I dreamed of. Over the last couple of months, we've done a couple road trips to the Seattle and Portland areas, but otherwise most of our driving has been like any other -- inner city. We live a little bit outside Vancouver so we get more highway driving than usual, but in that time we've averaged roughly 225 Wh/Km over some 7000 Kms (the two road trips added to that quite a bit). To give you a sense of our driving styles, I tend to be the more consumption conscious one out of us two but even then I typically just enjoy the ride. Our range mode is off; we had it connected to the app for a while until the vampire drain became too much; and usually drive with the climate control on. As for Vancouver weather and terrain, outside of a week in late October-ish that was in the -1 to -8 range, while it's gradually been getting colder, it's usually been in the 3 to 12 range (Celsius). Vancouver can be hilly at times, but our weekly commutes stay relatively flat. Even if we do run into hills, it's nothing that would seriously affect our range. Finally, we park the car in our garage to charge overnight and it's had the .34 software update since delivery, until... AFTER Two weeks ago we got the .42 software update. I identified the above to point out that all of our driving habits, commutes, weather, etc. has been the same even after the update. Since then, our steady average consumption rate quickly jumped seemingly overnight from 225 Wh/Km to 280, driving somewhat conservatively. If I try my best, I can hit 260. Similarly, if I don't pay attention to consumption then I'll hover around 300. Before, I'd be able to hit 190, but no more. Additionally, immediately upon starting a drive, the current trip average starts around 1,000 Wh/Km and takes quite a few kms to get down to 300. One time, when we had 6 passengers, we got in the car and turned on all of the seat heaters and saw a steady consumption rate of 1,800! Remember that this is above freezing weather. I mean, I understand it takes some extra battery but this is insane. What's even weirder is that I had one short drive in the middle of this sudden jump in consumption rate where the immediately upon starting to drive, the consumption was in the high 100s and quickly fell to just over 100 for the 5 minute drive. While it would've been great had that lasted, how does that make sense?! Well, the next time I drove the car, it was back to it's high usage ways. I also got winter tires installed a week ago but that was already after the fact and it had no noticeable effect on the range and consumption either way. CAUSES So with that said laid out, what could possibly be the cause? Better yet, have any of you experienced something similar? I called Tesla and they first suggested it was the colder weather, the battery taking time to warm up, etc. Firstly, it's not even freezing and yet it's supposed to be reasonable for me to lose 20 to 35% of my battery range? Also, the one cold period we had below freezing the Model X was perfectly fine and showed no sign of any issues. Of course they assumed I parked outside but I didn't. They then said that it's common to experience slight battery degradation after one month. Well, again, I understand a slight degradation, even 5%, but these numbers are ridiculous. Plus, it's been 2 months. They then asked me some questions to help with troubleshooting, but they called me back tonight and said the engineer found that the car had no noticeable problems. So I have an appointment set for 2 weeks from now that I already had booked for a wheel alignment, so I have added this issue to their plate and hopefully they can find something then. I thought I'd share my story here in the meantime hoping the community can help solve it or share if they've had similar situations, and if so, what you did to fix it. Like I said, from my recollection, my average consumption rate changed within a day right around when I got the new software update, so that's the only thing I can possibly attribute it to. Nothing else has changed from before the problem to after. Thanks for reading!