I think if you hit Auto with AC button on, it'll sometimes start in Recirculation, then switch to outside air. Guess it has advantage sometime.
Well I open the doors to get the air temperature down before getting into the car. But yeah, obviously giving the HVAC unit the coolest air you have to work with will reduce its effort.
I don't have many experiences yet as I've had my C2 since Saturday but I drove to work without AC and had about 48mpg (mostly turnpike at 75mph) and then had it on going home (same route) and I only saw 1 mpg difference. I'll come back and update after I have more anecdotal evidence.
We have a 2008 Prius and a 2015 Prius; neither is a C though. I've noticed between 2 and 4 mpg loss with the A/C on. The higher the outside temperature the higher the mpg loss. It is hot here in the summer with 100-110 being normal for the hottest 6 weeks.
After a week I'm not noticing a big difference with the AC useage. At least not enough to make me not use the AC. It's been HOT here in Kansas!
