I don't use it.
I live in so cal and have never once since i bought my JKU a year and a half ago turned on the a/c. when its warm or hot out i either roll the windows down or i just take off more items from the jeep ex. soft top replaced with bikini top then full doors replaced with tube doors, i imagine if i did some wheeling up near barstow or death valley in the summer then i might need it but i have always run areas like that either in spring or fall. just my :twocents: