I use 2 heat pads underneath mine, and no melting has taken place I am planning on putting a lamp in soon for the winter, it just gets perty cold in my boyfriend's old house. Stays around 70 or so, but still too cool for the air temp. I plan on using hardware cloth, it's wire mesh covered with rubber/plastic so Amani won't rub her nose on that rough wire (Marla told me about it, Thanks Marla!)

Also, you don't necessarily have to cut a hole in the lid for a lamp. If you can just use heat pads(with a thermostat attached of course) and get the temps right in the enclosure, then you are fine. Lamps kill humidity, even though keeping humidity in a rubbermaid/sterilite/iris container is very easy. Just be sure to use a digital thermometer/hygrometer as the dial thermos/hygros they sell at pet stores are usually very inaccurate and you could be cooking or freezing your snake and not know it. Those can be found at WalMart for $15, and the brand is AccuRite.

I know I'm just blabbing on forever, but it's important stuff Hope it helped some.