Well its a tough situation...Keep them cooler by keepeing humidity lower than it should be, or keeping them hotter than they should be with the proper humidity. I say keep the air circulating in the room and around the tank (not in it, will dry them out too fast). Watch them closely, mist them immediately if they are looking lethargic or sickly on hot days. No direct sunlight etc... Might be worth it to buy a cheap window unit, your geckos would appreciate it I'm sure, anyways good luck.
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12.5.15 Crested Geckos
0.1 Leopard Gecko
0.0.1 Tomato Frog
1.1 Ball Python
0.0.2 Poison Dart frog
www.geckoharmony.com