Heating Reptile Enclosures

The Importance of Thermostats

In choosing to maintain reptiles in captivity, we as keepers take on the responsibility of providing these animals with an environment tailored to their specific needs in order to promote good heath and expression of natural behaviours, and so ensure high standards of animal welfare. Within that context we acknowledge the importance of providing the correct temperatures needed for reptiles to thrive, and this may only be accurately attained through the use of thermostats.

Simply put, the thermostat is one of the single most important pieces of equipment used in herpetoculture, as not only are they essential for regulating the temperatures inside the reptile enclosure within specified limits suitable for the species concerned, but most importantly they also prevent those temperatures from becoming excessively high. In the height of the summer, a thermostat can literally make the difference between reptiles living or dying, as restrained within the enclosures we provide for them they are not able to escape the high temperatures generated from an unregulated, non-thermostatically controlled heating system. The death of reptiles from overheating, whether it be a single specimen kept as a pet or a whole collection of valuable breeding animals, is simply unacceptable given how easily such a situation may be avoided. The range, availability, and ease of use of various models of specially-designed reptile thermostats produced today means there is no excuse for not using them, and their importance cannot ever be emphasised enough.

There are several major brands of reptile-specific thermostats commonly available, with manufacturing several different models for use with different heating systems. The traditional favourite – a company called Microclimate® - produce a very popular and reliable choice of thermostats, including the commonly used B1 Dimmer stat model, used for regulating the output of basking bulbs and ceramic heaters. These may be purchased as a single unit designed to control a single heat element, or as a twin-channel stat which may be used to control two separate enclosures. Also available are ‘Magic-Eye’ stats, which utilise a photo-sensitive module to detect changes in the level of daylight and so adjust the temperature accordingly for day and night-time. Pulse-proportional thermostats are suitable for use with higher-wattage non-light emitting heating systems such as ceramics and AHS, and specially designed Mat-Stats are available for regulating the temperatures generated by heat mats and strips of all sizes. More recently, a number of computer-controlled or digital thermostats have become available, having been developed in the USA. These will no doubt soon take over the older style analogue thermostats as their digital temperature settings and real time monitoring systems are considered by many keepers to be much more accurate and user friendly.

Heat Mats & Strips

Electrical heat mats and strips specially designed for use in herpetoculture are one of the simplest methods of providing essential heat to reptile and amphibian species. Consisting of a sheet of heating elements sandwiched inside a laminate cover, heat mats radiate heat in proportion to the amount of pressure placed upon them. The advantages of heat mats is that they are relatively cheap to purchase and run, and can be used either as a 24 hour heat source, or in conjunction with basking bulbs to provide an ambient night-time warmth. They are thin and light and can be positioned on either the floor of the enclosure, on the walls or even the ceiling if needed. Heat mats are available in a range of sizes, from the tiny 2x2 inches mini-mat produced for use in small spider tanks, right up to models several feet square designed for larger enclosures, as well as the long, thin strip versions favoured by breeders to supply warmth where several hatchling tubs are arranged in rows. One disadvantage of heat mats is that they must never be used in a situation where heavy-bodied reptiles such as the boidae species of snake or large monitors can come into direct contact with them, as these animals are likely to suffer thermal burns from prolonged periods of sitting on or against them.

Heat mats may be used inside or outside of the enclosure; - in the case of plastic tanks and tubs the heat mat is usually laid on top of a sturdy, heat-resistant surface and the enclosure positioned on top of it so that heat radiates up through the floor to provide an area of warmth within. Alternatively, in the case of arboreal species such as chameleons or tree frogs, the heat mat may be positioned vertically on the wall of the enclosure using heat-proof electrical tape along the clear edges of the mat to secure it in place. This method is particularly useful for heating enclosures where high levels of humidity are required, as positioning the heat mat on the outside prevents it from being damaged by high ambient moisture. However, great care must be taken that heat mats used in this manner are operated in conjunction with reliable mat-stats in order to control the temperature at appropriate levels. Otherwise the heat radiated by the mat may cause plastic enclosures to warp and become misshapen, as well as possibly harming the occupant. Heat mats can be used with glass tanks but only with extreme caution, as these are liable to crack if the glass becomes overheated. In order to avoid this, heat mats should only be positioned on the sides of the glass tank rather than underneath, and care must be taken to ensure that there is plenty of good ventilation circulating around the area where the heat mat is affixed.

Where heat mats are to be used for heating wooden vivaria, it is important that they only be used on the inside of the enclosure, where again they may be carefully fixed in place using strips of electrical tape to stick them firmly to the interior surface. Mats secured to the floor are then regulated with a mat-stat, and can be hidden for aesthetic reasons using a thin layer of dry substrate.  Heat mats will usually tolerate intermittent bouts of moisture, such as daily misting of the vivarium for example, but will quickly fail if accidently submerged in water. As a result all drinking bowls and water features should be positioned at the opposite end of the vivarium to avoid accidental spillages from damaging the mats. Although some keepers will insist on positioning their heat mats underneath wooden vivaria, this is not recommended as the greatly increased weight stress on the electrical elements of the mat results in a massively increased heat output. Not only will this cause a heat mat to ‘burn out’ prematurely and so require constant replacement, but it also poses a significant fire risk that is totally unacceptable with regards to its implications for the animals housed within.

Heat Bulbs

Heat bulbs are most commonly used in wooden vivaria and large glass enclosures, where it is essential that they be run in conjunction with an appropriate dimming thermostat, and protected by means of a purpose-built wire cage to prevent the reptile from coming into contact with the hot bulb and injuring itself. Heat bulbs should only be used in heat-resistant purpose built fittings available from reptile supply companies, and in large enclosures they can be used with metallic reflectors designed to direct the heat onto a particular basking spot. The range of commercially produced reptile heat bulbs is extensive, with different features designed for a particular use, and ranging in price from just a few pounds up to the region of £60 plus for some of the higher wattage dual function bulbs. Most are available in a range of wattages for use in different size vivaria, usually 40W, 60W, 100W, and 150W, and are usually manufactured with the standard edison screw fitting, although some models are still available in a bayonet fitting. Heat bulbs should not be used in enclosures containing amphibian species, especially frogs, as the intense heat they generate will quickly cause them to dehydrate and will damage their delicate skin.

Reflectors

Uncoloured reflector bulbs are the standard bulb type used to provide a tight beam of strong heat and light in which diurnal reptiles will bask, but must be switched off at night to allow the ambient temperature to drop to the appropriate level for the species concerned. This also allows a period of darkness and so a regular day-night cycle. Non-tight beam versions are also available which provide a greater area of heat coverage and an increased ambient temperature. Uncoloured reflectors are the most commonly used reptile heat bulbs and are generally appropriate for use with many species, from monitors to bearded dragons and skinks. Coloured reflector bulbs in shades of green, yellow and blue are also sometimes used to create dramatic daytime colour effects within enclosures, although what effect this may have on reptiles’ visual perception and behaviour is not known and so their use is discouraged.

Infra-Red

Infra-red bulbs should not be confused with red-coloured bulbs; they are manufactured from truly red glass as opposed to clear glass that has been painted red. Infra-red bulbs generate heat energy of a lower wavelength to that of clear reflectors, and so provide a more deeply penetrating heat as well as a soft red light. This is particularly useful in enclosures housing nocturnal species, whose eyesight may otherwise be damaged by the bright glare from standard basking bulbs. It is thought that infra-red light does not interfere with a reptiles’ day-night cycle, so infra-red bulbs may also be used as a 24 hour heat source. However, the stronger heat generated by these bulbs acts as a powerful desiccant and will quickly dry the ambient moisture out of the air, so regular mistings are needed in order to maintain appropriate humidity levels within the vivarium.

UV/Heat Mercury Bulbs

These high wattage dual purpose reflector bulbs are designed to not only generate a strong heat beam, but also radiate the broad-spectrum ultra-violet light wavelengths usually provided by means of a separate lighting system. They are specifically designed for use in very large enclosures containing UV requiring species such as iguanas, and although they are relatively expensive in terms of purchasing price and running costs the high UV output they produce has proven particularly useful in stimulating breeding behaviour in these large lizards in contrast to traditional UV systems. These bulbs should be mounted at least 3 feet above the desired basking area and as with standard reflectors need to be switched off at night.

Night-Time Bulbs

Night-time bulbs are designed to allow reptile keepers to view the nocturnal activities of their animals without disturbing their natural day-night cycles, as well as producing very low levels of ambient night-time warmth appropriate for most species. They are manufactured from very dark blue glass that generates a soft purplish-coloured light, and are available in wattages of between 15W and 40W.

Ceramic Heaters

Although many ceramic heaters resemble bulbs in their appearance, they are classed as a separate heating system as they generate only heat, rather than heat and light. Only suitable for use in large wooden or brick-built enclosures, these heaters are typically constructed from a white, heat-resistant ceramic material containing an embedded heating element and may be conical (cone-shaped) or bulb-shaped in design. They generate a particularly intense, deep heat that must be carefully controlled with a thermostat, and require special ceramic fittings and often a reflector with a built-in guard in order to prevent the ceiling of the enclosure becoming scorched. Ceramic heaters are particularly appropriate for heating enclosures containing large reptiles where they can be used as a 24 hour heat source. However, they can be expensive to run and require careful and regular maintenance as faulty heaters can pose a fire risk.

AHS Systems

Advanced Heating Systems (AHS) consist of thermostatically controlled heat elements arranged inside a protective outer case, usually rectangular in shape that are mounted on the walls of very large enclosures to act as radiators, warming the surrounding air to the desired temperature and creating convection currents and thus air movement in the process. AHS systems are best used for heating larger species of snakes and monitors, but are not suitable for use in enclosures where high humidity levels are required.

Other Heating Systems – Hot-Rocks, Cables and Plates

Various other heating systems apart from those detailed above are occasionally offered for sale in pet shops and from reptile supply companies. One of these alternative systems are the electronically controlled hot-rocks; - generally a resin or ceramic naturalistic-effect ‘rock’ containing a heating element upon which the reptile will sit and bask. For many years these hot-rocks have been associated with horrific thermal burns in numerous species and as a result have become very unpopular, with many keepers actively avoiding and condemning their use as unsafe. Recently, Exo-Terra® launched a new thermostatically-controlled hot-rock model designed to be more reliable and safer to use, as the built-in thermostat aims to prevent the rock’s surface temperature form reaching dangerously high levels. Still, continuing suspicions within the herpetological communities mean these are still seldom used, with most keepers preferring to use the more traditional heat mat and bulb heating systems. Other heat sources include heat-cables, consisting of long thin insulated heat-emitting wires designed to be buried within damp substrates to increase the ambient humidity, and large flat ceramic heat plates or ‘reptile radiators’ which are fixed to the vivarium ceiling to create a localised area of heat for arboreal species to bask in.