We actually have been out of town since Friday so I haven't had a chance to set up the geckos in them yet. I did test them before I left and they work great. The heat is from the back though, so if you are wanting heat from below you may want to go with building your own. This week I am planning on getting some foil tape and putting it on the boxes to see if I can transfer some of the heat to the bottom. I'll definitely post about the results.