I don't believe in any type of under substrate heating for any type of indoor tort, only pig blankets for very large outdoor torts. It is unnatural for them to get heat from below. Using a heat bulb is a natural way to provide heat and a safe alternative (provided you take the proper precautions against fire hazard). I don't like the idea that it becomes warmer as they dig down nor the potential for overheating. Also, I don't like to keep my tort too warm at night--I like to keep him at the lower end of his day temps, similar to in the wild, although I do believe that keeping babies warmer than adults is necessary as they are fragile. I suggest owners do the research and make their own informed decision as to what they think is the right choice. Plenty of people use heat mats for torts but I disagree with it. I like the idea of radiant head panels to provide heat from above, but they are expensive and would be tough to install on an open top tort table. If you do use a heat mat, you definitely need to have it on only part of the enclosure, and if you can hook up a thermostat or some sort of fail safe for it to kick off over a particular temperature that is ideal. I just don't see the reason to use a heat mat when I heat bulb will provide heat with no negatives, only positives. Also, some torts (like mine sometimes) will chose to sleep in the unheated area. Not much you can do about that besides pick them up and put them where you want them to sleep (mine will then typically go back to where he wants to sleep). Best wishes.