I don't know how everyone else copes during the hot summer months but I live in the mid-west-about 100 miles So. of Chicago and I absolutely have to run the ac when the temps hit 85 plus.
I also shut my diurnal reptiles lights off during the hottest part of the day.
Funny thing- I haven't had any problems with the Leos viv's temps-probably because they don't need use any basking lights.
I do turn down their heat mats to compensate for the higher temps in the house as I keep my house at about 78-just enough to take most of the humidity out of the air that we are famous for having here year round-YUCK!!
I suppose that you could use a fan over the screen top of a viv to bring some cooler air into the viv if you can't run your ac.
I know that it works for fish tanks.
Sandy