What about just laying a thick foam mat with insulating properties between the 2 cages ? Or does this situation need an air gap like Flexwatt ? The RHP, as of now, is heating up the top of my existing cage to 93-95ish, if there was a foam rubber mat, it should make it harder to transfer heat into the top cage. From what I read about RHP's...they can be placed against any surface. insulating over top of it shouldn't be a problem then. IDK.