I cover the backs & sides of many of my glass tanks too- depending on the occupants. I like to buy & install scenery first, then I might also insulate behind that (poster board with foam core is very effective & easy to install, as is just corrugated cardboard- or you can use other materials too- sheet cork, carpet tiles, plastic bubble sheets, thin plywood, or even sheet styro-foam) & if you use scenery or wallpaper, you won't see the "insulation" but it will help keep the warmth in & your snake cozy. Many things work-![]()