I was brainstorming last night and thinking of a way to attach a heat mat to the side. I had forgotten about those heated cables or heat tape. Good idea!
The heat lamp is outside the cabinet and aimed at the side of it. It was the proximity of the cabinet as it was put back that created this situation-- but now I'm definitely not able to sleep until we get this situation changed.
The UV light is very safe. It doesn't get very hot and it's in the existing light bulb outlet that came with the cabinet. We just put the cage around it to prevent the chameleon from having direct contact with it.
The habitat is large enough and well-ventilated enough that we've never had to worry about overheating-- the chameleon simply moves around to different areas to regulate his temperature. Love the idea of a heated branch!