The best thing you could do is get rid of the CHE and go for some UTH (under tank heaters). Covering 2/3 to 3/4 of the top screen with foil or something similar, as was mentioned already, is a good tip too.

I did that, and ended up getting a larger surface area water bowl so my snake can soak a bit if he wants. With the new water bowl, I've never had to spray again, period. In fact, it gets slightly too humid in there now.