Good Find! I was wondering that also. One thing i'm not use to is that fact it has to be set to either recirc-Or Sucking Air from the outside. My Saturn and Silverado never had this feature.

 

I wish they didn't make it default back to vent every time you cut the car off. Out here where it gets 110, I like to use the remote start for a few minutes before I go out. And since the car gets cooler with recirc it would be a bonus.

I figured out the thing about A/C on recirc shortly after getting the HHR as well. I thought it was going to be great if I could get air that cold without turning on the A/C. Opened the hood to check and sure enough the A/C was engaged.

 

Actually, according to GM, the car cools off faster by NOT using the recirc A/C, because, when using the outside air, it is attempting to cool the interior of the car with the ambient air, which is generally cooler that interior heat soaked air (sometimes 160 degrees). After a short time of driving with the windows down or using the outside A/C then using the recirc is efficient.

GM, as well as other manufacturers, have used this method for years and described this use in previous Owners Manuals....but you were instructed to switch manually. As you know, the car now switches to outside anytime the car is turned off and restarted. I guess they make the presumption the vehicle is parked long enough to experience heat soak.