I seriously dought that leaving the a/c on at 85-90 degrees is going to make much difference other than removing $$ from you pocket.
2014 GMC 3500 Dually diesel 4x4 CCLB. Curt q24.
2011 Montana 3455 SA. 6 point level up. Disc brakes.
Progressive EMS. Valterra tank valves. Sailun G637 tires. ARP fridge control. All led lighting. Mor Ryde IS to be installed 6/2020