I am in Houston and mine works great. It does take a few minutes to cool down. I do find that it works best and fastest if you leave the temp around 68 and on recirc, with the rear AC on full. I do not have my windows tinted yet, just the factory rear. When I get time to those it will help alot. If it is really hot I crack my front window and open the rear sail windows and drive about 2 minutes and it sucks all of the hot air right out. Just a couple of things to try that work for me in the good old southern heat.