Will be in the hot south/west U.S. this summer. Daily temps reach 100 or more. Any chance of "over using" or harming the air conditioning system? Can I set it to the lowest setting and just leave it there? (It says "Lo" on the display). The AC is the one area of my Prius that confuses me. I've seen members discuss the "heat pump." Not sure if that is related to the AC. What actually powers the system in the Prius? If I understand correctly, the Prius AC is not like a conventional system as in a non-hybrid vehicle. Thanks in advance. (I do have tinted windows, and use a heat shield when parked. It gets very hot when driving).