Turn off the UTH (& any & all other sources of heat to cage) once your house is staying 80*+. How hot does your house get? Snakes can only take so much...
Temporarily you could hold him in a secure cloth bag, inside a thick styrofoam food-shipping box or ice chest...and inside that a jar of cool to cold water will help
keep the temps. down but you'll have to monitor it.
In a dry climate, a fan blowing thru damp towel helps to cool the air. Cover & insulate your windows to keep out as much heat/sun as you can...good luck.