Will test it the next time I get a new batch of sentry clips that I need to copy off and see if/how it changes over time.
Finally tested the aircon power usage. Did it at night so it wouldn't have been under much stress. Ambient temp around 24C, interior temp read the same. I sat in the passenger seat and used the app to turn the aircon on. Aircon was set to 22C, auto mode. Screen was left off. The car is plugged in to the wall charger, and on standby to start charging at 8:00am the next day.
I used the Tesla app (Powerwall section) to monitor power consumption. As a baseline, with me sitting in the car and the aircon off the house pulls around 400W.
Started the test at 8:22pm by turning the aircon on via the app; this increases power usage by about 2kW.
It didn't take long for the interior temperature to stabilize at 22C. As it ran, the power consumption would fluctuate somewhat but only rarely would it drop below about 1.5kW. And when it did, only very briefly. Kind of like this:
...and then 12 seconds later:
After ~15 minutes this pattern hadn't changed. I switched the aircon off at 8:40pm and the house went back to its baseline power usage:
So in theory you can gain about 10% in range by keeping the A/C off (assuming you drive the car for ~4 hours at ~100kph, you'll end up spending 6-8kWh on aircon). That seems to align with my actual driving experience, as I get a reported average of ~170Wh/km with the aircon on and ~150 Wh/km with it off (for local driving on approximately the same routes).
For comparison, here's what my 7.4kW split-system/inverter aircon looks like when switched on during a warm January day:
It definitely pulls a higher peak load than the Model 3 (~4.5kW), but then settles in at the same consumption (or slightly better, at ~1.3 kW after accounting for baseline usage) to cool a much larger area under much warmer conditions.
If anyone is interested I can graph the Model 3 A/C using the same tool (just have to redo the test during the day; the Enphase thing can't see nightime consumption because of the Tesla batteries).