Well, it shouldent really be a fcator of "how hot untill it burs," but it should be more like "Ok, is it at 80/90 degrees and no lower/higher?" Heat pads can and WILL, without a doubt, get to beover 100-120degrees without a thermostat, so I would HIGHTLY recomend one, and I would say set it so that it gets no higher than like 93 degrees, but of course the closer to 90 the better. (assuming its the warm said- but same thing if its the cool side, just 84/80)