These things have a friggin mind of their own. I use the recirc. over the summer for two reasons; 1) it`s definitely easier on the compressor, and 2) the cabin air has less humidity to it because its not drawing in outside air. Plus, better gas millage due to the compressor not running as much. However,on a road trip I will switch to out side air for a brief time. Just to let in some fresh air. The other plus to recirc. is; You have no outside smells i.e diesel fumes etc. coming in the vehicle.