Basic guide to heating
One of the most frequently asked questions when it comes to keeping reptiles is how to provide the heat requirements for a particular species. So this has prompted me to put together this short post which hopefully goes some way to answering these questions.
So let us first look at what we are attempting to achieve. Well that's the easy part. We want to provide a thermal gradient within the enclosure where the reptile has access to a temperature that's close to that found in its natural habitat, but also a means of removing itself away from that heat to cool off. This process is called thermo-regulation. Now this thermal gradient can be across the length of the enclosure, or for reptiles that are predominately arboreal, in height.
One thing that people seem to get hung up on is the exact temperature for the hot spot. It doesn't matter if your hot spot temperature is a degree or two above the temperature stipulated in a care sheet, book or website. However if it's an excessive amount above that sweet spot then it will cause problems in the gradient as the cool side will then be at the "recommended" temperature and the snake or lizard can't cool off. So if you have a python or boa that has a suggested hot spot of 32c, then it doesn't matter if the true temperature is 31C or 33C. Anything above 38C in anything other than a large walk in enclosure will cause the problem mentioned above.
So how do we provide this heat? Well there are several options. Firstly heat mats and heat cables, next there is the humble spot lamp or heat lamp, and then we have ceramic heaters. Let's have a look at each group, and obviously some methods are not suitable for some enclosures.
Heat Mats and Cables
Heat cables tend to be used in rack systems. They are made from high resistance wire that warms up when electrical current is passed through it. It's basically a long, flexible low temperature heating element. They come in lengths typically 8m-10m which allow it to be laid in a zig-zag loop along each shelf of the rack before being connected to a thermostat.
Heat mats come in a variety of sizes and power ratings to suit most needs. They are made by laminating carbon elements between two clear plastic sheets. The plastic has a high temperature rating, but there have been issues where this has melted and even lead to a fire, more on that later. Most people tend to use them either externally where the tub or glass / plastic enclosure sits on top of the mat which is fine, but when the inside floor of the enclosure is covered with a substrate, the performance of the mat is compromised somewhat. Where the enclosure is large enough, such as a traditional glass fronted wooden vivarium the mat can be installed internally. Again, people often place this at one end of the enclosure on the floor. Again this is fine, but the performance will be reduced once you add a substrate. However if you follow the instructions they are equally suited to mounting on the side or rear wall at one end of the vivarium. The issue is that people believe these mats are designed to work like a normal element, they are not. They are designed to emit low wavelength infra-red energy which penetrates deep into the skin of the reptile that's in its path. Covering a mat with a deep layer of substrate (which is typically wood based) prevents the infra-red energy from escaping so heat is generated within the mat and substrate. Most think this is how the mat is designed to function, but whilst it works to a degree with small snakes and lizards, it is not good practice with larger heavy bodied animals.
If you do your research and read up on heat mats and their usage you will at some point see the term thermal blocking being discussed. Thermal blocking is where a large cold animal sits on the mat and draws all the energy from the mat faster than it can produce it, so in essence the snake can't get warm. Now where this becomes a danger to the snake or lizard is when the thermostat probe is attached to the mat and the cold animal sits on the probe. It reads the temperature and as its way below the set point the thermostat turns the mat on, and keeps it on as the set point hasn't been reached. The mat warms up to a point where it starts to produce localised burning of the animals skin. By the time the internal trigger in the snake / lizard triggers it to move off the mat, which is normally the set point, the damage is done. The result in snakes is that the skin between the folds of the belly scales becomes pink / red as if sun burnt. This doesn't really become a problem with smaller animals such as corn snakes, king snakes etc.
Lamps & bulbs
The use of incandescent lamps to heat a vivarium has been around for decades. In fact before keeping reptiles in captivity became as popular as it has been in recent times, the humble light bulb was the only means of heating an enclosure. These days, lamps are seldom used as technology has moved on with the development of ceramic heaters, but in some situations they do have their use. They must be used with a dimmer stat to prevent the lamp from overheating the enclosure. The main disadvantage with using lamps is that in order to maintain the heat 24/7 they need to be on 24/7 so the animal won't get a night day photo period. The use of red lamps was thought to be the ideal compromise as it was thought that most reptiles couldn't see the red light that they emitted. However recently there has been some research to suggest that this isn't the case and the wave length of these lamps is still detected by the snake. Some people will often use a spot lamp on a timer to provide a localised hotspot available for a few hours during the day.
Ceramic heaters & tube heaters are the ideal method for heating any vivarium. Tube heaters come in lengths from 30cm to 2m and provide an excellent background heat where vivariums are housed in cold rooms. They lack the ability to provide directional heat, but if placed in a suitable open box with a mesh front the top of the box can provide a warm shelf for the animal to bask on. One disadvantage of tube heaters is their size for a given wattage, which tends to rule them out as a primary heat source.
Conical / mushroom and trough ceramics have been marketed as the primary heat source since the late 1980's. They work in two ways, by emitting infra-red energy and in the process, warming the surrounding air when enclosed in a vivarium. However in doing so the surface temperature becomes extremely hot. Even on a thermostat with the set point at 32C, the surface temperature of a ceramic heater can be 180C - 200C. So they must be guarded. When choosing a guard ensure that it has at least 40mm gap between it and the face of the element, otherwise the guard could become hot enough to inflict a burn.
One of the other disadvantages with conical / mushroom ceramics is their size. They need a tall vivarium in order to have enough clearance from the bottom of the guard and the substrate below, making them impractical in 15" / 18" tall vivariums. This is where trough ceramics and plate ceramics come into their own. A trough ceramic has the same advantages as a conical / mushroom ceramic, but in addition provides a larger heat area (making them ideal for large snakes and lizards) and as they don't occupy so much depth can be fitted in vivariums as low as 15" (38cm) tall vivarium without issue, even when a suitable guard is fitted.
Where height is really an issue, or you want a heater to provide a large heated area without being intrusive (such as in a main display enclosure) then a reptile radiator is the best option. These are rectangular ceramic plates about the size of a single sheet of A4 paper, and just 35mm deep. They were developed from the original powerplate (which I still have), and are designed to radiate the heat down on the animal than out the back (unlike the original powerplate which came with a heat resistant fibreglass matt which needed to be placed between the plate and the surface it was attached to). These are rated at 75watts and like all other forms of ceramics need to be guarded.
"Proper" reptile basking lamps can be had for between £5 and £10 making them the cheapest form of heating available.
Mats are a cheap way to provide the heating requirements needed for keeping reptiles. The average price at the time of writing this article is between £8 and £30 depending on the wattage and manufacture. I would personally recommend you purchase a recognised brand such as Ultratherm / Habistat. Cheap no name mats from e-bay have been known to catch fire, even when used correctly, or are not constructed properly to comply with the double insulation standard and risk electrocution.
£25 - £30 for a conical / mushroom ceramic, £12-£15 for the ceramic ES holder, and £12 - £25 for a reflector. Add to it the cost of a suitable guard (£16 - £25) so expect to pay around £65 to £100 depending on wattage and fittings.
Trough ceramics are seldom available from normal retail outlets and have to be sourced through specialist suppliers. The cost for a complete kit with a 150w element, reflector, guard and accessories including heat resistance wire is around £96 plus postage (contact me for details on where to obtain these if interested).
Lastly the reptile radiator with guard will set you back around £75.
All forms of heating MUST be controlled by a thermostat that has been designed for use with reptiles in mind. There are three leading manufactures in this field, Microclimate, Habistat and Lucky Reptile, the latter being new to the hobby compared to the other two who have been around for decades.
There are three types of thermostat, straight on/off types, dimmer stats, and pulse proportional. Mats tend to be controlled by on/off stats, lamps by dimming stats, and ceramics by pulse proportional stats. All come with probes and probe placement is critical to maintaining the correct temperature.
The closer to the heat source the more precise the control will be. Remember that the thermostat is responding to the temperature of the probe, so if the probe is mounted away from the heat it won't trip until it reaches the setting of the dial or programming. The result is the hot spot can be way above what we want it. I always recommend placing the probe directly in line with the heat source when using lamps or ceramics, but at a distance mid way between the bottom of the guard and the substrate. Then use an IR temperature gun (available from Amazon, e-bay etc) and use it to monitor and set the desired hot spot rather than the values on the dial.
For mats, ideally place the probe in the middle of one of the panels. The issue is how to attach the probe. Tape isn't ideal as it can work loose and become attached to the animal. Hot glue works well, but needs to be able to withstand the constant 30+ degree centigrade the mat will run at.
Hopefully this post has answered some of the basic questions that get asked. It's based on my 31 years (at the time of posting) of keeping snakes and lizards, and 20 years electronics experience including the research and development of my own multi-thermostat unit that has been running my four vivs for the past nine years. If you have any further questions on heating just post them in the form below and we will do our best to advise.
Last edited by Malc; 30-01-2018 at 01:07 AM.. Reason: formatting - forum doesn't like ' and "
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