On long trips, I've been getting about 70% of ideal range, or equivalently 80% of rated range, in very cold conditions (e.g. -15C to -20C), with the heat operating in Range Mode. At 80 kph (50 mph) I can drive around 330 km (205 mi) on a full Range charge, without freezing! Cabin heat appears to draw 5-6 kW at full power (hard to tell exactly from the power gauge). The pack heater draws about the same amount at full power (it does ramp up/down as needed). I've been using a spreadsheet derived from the above, plus the numbers on Tesla's web site (from their range calculator and adding data from their rough graph) to calculate range and power draw under various conditions. Here are some observations, based on driving 80-90 kph (50-55 mph) in the cold: Reducing your speed by 1 kph gives you about 5 km of extra range. Or equivalently 1 mph gives you 5 miles of extra range. Saving 1 kW power will get you about 16 km (10 miles) more range. Going from full cabin heat to no heat will give you 68 km (43 miles) more range. (Note: ballpark only - very sensitive to conditions) This is equivalent to slowing down by 5 mph. Typical HID headlights use about 35 watts each, so turning your headlights on probably pulls about 70 watts. Doing that reduces your range by about 1 km (0.6 miles). So don't panic if the sun goes down. The cold matters, not the light. Seat heaters likely draw a similar amount to the headlights. Use them liberally. Dimming the display might save you 15 watts (guesstimate). That will get you 300 meters (1000 feet). Not worth bothering with this sort of thing. Charging your phone will consume at most 2.5 watts (USB power limit). That will consume 100 meters of range (300 feet). Go ahead and charge your phone - you might need it! In short don't sweat the small stuff. If you vigorously use all the electronics in the car you might knock a mile off your range. You can make up for that by slowing down by a mere 0.2 mph. Full power on the pack heater and full cabin heat could reduce your range by 80 km (50 miles) if they were running full blast all the time. Fortunately the pack heater ramps down after 20 minutes or so, and you can't run the cabin heat at full power for long without breaking into a sweat. Still, it's a good idea to leave on a long trip with a toasty pack and cabin. About 20 minutes before your charge is due to finish, turn on your cabin heater. Once the charge is complete leave immediately, while the pack and cabin are toasty. The single most important thing you can do to extend range is to slow down. However, when there is extra power draw the optimum speed is higher. That's because a fixed power draw like a heater consumes more pack capacity the longer it is running. If you're going slower, it's running for a longer time. The sweet spot in cold temperatures is probably 60 to 70 kph (40 to 45 mph). Instead of turning the heat off altogether, turn on Range Mode to limit the cabin heat power. Then drive 5 kph (3 mph) slower to make up for the power usage. You'll be a lot more comfortable!