Well I couldn't put it on the top, it's too close to the ceiling, and the other bonus of having it on the side is that it regulates the temperature in the mesh cage MUCH better than just top heat. The thermal gradient moves across the enclosure, so he can stay in the foliage and keep warm or go cool down.

Heres my setup. 18"x48" chrome racks. I used half for my smaller cages and the other half I jigsawed the legs in half to hold my 2'x4' cages....yup my drainage tubs need emptied LoL