I have pretty much the same set up as you. I run a humidifier on low in this room and where the location of this room the sun is always on it. I have a radiator heater in there but it hardly ever turns on. Sunny days it's 95 in this room and suffocating humidity 85% sometimes. I can't believe no mold has started growing on the walls. Well I'm changing my babies over to a closed chamber. Keeping a 12x10 room like this isn't very efficient. I have aquatic turtles in this room as well so that really helps my humidity.Here is a pic of my temporary fix. It has also done much better. Still need to work on my night time temps and basking spot temps but I should have my solution here in the next couple days.