ceramic heaters are NICE, I keep two on my 75 gallon enclosure with the carpet python in it. The thing is, they are really expensive and when you have 66 snakes they just wont cut it. since i have custom built caging and they are solid units, the light below one tank warms the bottom of the one above it, and so i only need to use very low wattage bulbs to efficiently heat my enclousres. anything too high, and my snakes would fry
I don't use heat on any snakes at night except the carpet pythons. I've never had a problem and when compared to their wild habitat, my snake room is still warmer at night than what it would be outside in summer!