I have been in the process of building custom cages for my snakes but for now I have all of them in glass tanks with screen tops. I have been fighting keeping in heat and humidity seeing how I live in an old dry drafty house. I have tried the usual tricks of damp towels over the screen, I have made custom masonite covers to put over the screen, plexiglass and so far I have not had satisfactory results with any of those options. I was at the local hardware store the other day and seen a product that was foil covered bubble wrap that claimed to stop 97% of radiant heat loss. I bought a roll and decided to try covering the screen top with that and BINGO! My temps went up due to no lack of radiant heat loss and humidity also went up because the foil does not absorb moisture. My temps have been running about 86 deg. ambient / hot side and humidity is consistently about 60%. I am very happy with the way this product has worked for me!!!!