My house gets very cold at night and i was having trouble holding night time ambient temps so as a cheap insulation solution i got some polysterene (styrofoam?) packing from round PCs at work and cut it to size and taped that round 3 sides of the enclosure - It's really helped so you may want to try that.

Some really good advice on here - obviously the paragraphs thing was great advice for your snake - please let us know how you taught it to read!