It does require a thermostat as do all heat sources. There are different schools of thoughts on probe placement. Mostly on what end of the enclosure the probe is placed. I hang mine about 6 inches from the bottom; along the wall at the end of the enclosure where the RHP is mounted. Once you obtain the temperature you are looking for, you can measure the temp on the cool side to see if the gradient meets your snakes needs. I would also experiment w/ the probe on both ends to see which gives you the best results. Keep adjusting the thermostat to find the perfect balance of hot side vs cool side.