hi todd, my thrmostat failed in the open mode last winter while driving across canada at -50deg....it was definitely _not_ fun. when i arrived at home i replaced it with a 92 deg cent. one...there's also an 85 deg model. believe me you'll appreciate the warmth of the 92 deg stat on your toes. i had no problem in the summer in very hot weather. hth mike 86 5kcdtq