On the 6 ft bottom cage there is a AP flexwatt(?) UTH. I have 1/4 in board under that area along with foil to protect the carpet.

I like your idea for a riser. I wish I had done that from the start. I live alone, so it would be a major project for me to do that at this point. And I'm just not up to it. They are in a dedicated snake/guest room, so drafts are not an issue.

It is funny that I call it a guest room, any guest that stays over is too afraid to sleep in there with the snakes, so I'm the one that ends up sleeping in there.