If you close off the top it seems to do well. If you leave it open you lose it all heat/humidity. Just a fact of life. There is plenty of ventillation along the front and around the doors so I just cut pieces of plexi to fit in the openings on the top. I had some scrap plexi sitting around from my first tank's top so I just used that.
When its really dry, like now, I need to mist or run a humidifier for a few minutes a day, but RH in the room is only 40%. I like to keep it spot on 50%.
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My snake loves to climb, not sure how he manages to hang on some of the stuff that he does. He's 1250 grams and can wrap hang off of the suction cup that the thermometer probe is attached.