Substratum heating is a concept popular amongst commercial breeders. There are several ways to heat the substrate and the most common for commercial breeders is known as Flexwatt which is actually a manufacturer. The proper name of this type of substrate heater is heat tape. These types heat tape are generally used by commercial breeders who are using a “rack” system where the drawers slide in and out. Looking within the cavity when the drawer is removed the tape can be seen usually taped down to the rack shelf. Another type of “rack” heating is done using heat cables which are placed into a channel that is cut into the shelf and a piece of aluminum is then placed over the cable to allow for further dispersion of the heat.
U.T.H. or Under Tank Heaters are another method and is commonly used by non-breeders for heating singular enclosures which do not have a dense substrate such as bark or thin layers of washed play sand. The reason for not using this type of heater with a dense substrate is that the heat produced by these is only about ten degrees above ambient temperature and they cannot penetrate up through dense substrates of over ½”. This type of heater usually has a peel and stick quality so that it can be affixed to the bottom of the enclosure itself.