The Comprehensive Guide To Reptile Thermostats

What does a Reptile Thermostat Do?

Thermostats in simple terms, safely regulate heating equipment and maintain your desired temperature by regulating energy sent to the heating equipment. Thermostats have a sensory probe, which we place in the vivarium, this reads temperatures and allows the thermostat to calculate whether it needs to increase energy to the heating equipment or reduce it until it reads the desired temperature the user sets.

What Kinds of Thermostats Are There?

Now there are 3 main types of thermostats, each work in different ways and are suitable for different heating equipment.

On/Off Thermostat

These work by turning on, supplying energy to the heatmat, until it reaches the set temperature, then it turns off, when the temperature drops below the desired temperature the thermostat turns on again. Repeating in an on off fashion. These are also often called matstats as they are often used with heatmats. But they can also be used with heat cables.

Pulse Thermostat

A pulse thermostat works differently to the on off thermostat in the way it regulates energy to the heating device. The pulse thermostat pulses energy in a very rapid fashion that provides a very accurate temperature. Instead of turning off and on, the thermostat alters the frequency at which the pulses occur. If the temperature is too low, the frequency increases. If the temperature is too high the frequency decreases.

These are most frequently used on ceramic heat emitters, heatmats and heat cables. These are more accurate than on/off stats but are also more expensive. However, where increased accuracy is preferable like in a incubator for example, than a pulse thermostat is recommended.

Dimming thermostat

The dimming thermostat, as the name suggests, dims energy provided to the heating equipment. If the temperature is above the desired temperature the energy sent to the heating equipment is reduced. So the bulb will be allowed to run at full power then is slightly dimmed when appropriate to maintain a steady temperature. I mention bulb because this is the type of thermostat most commonly used with light emitting bulbs like halogen basking lamps because it does not blow the bulb like the over thermostat types, and it wont cause constant flashing.

This type of thermostat could be used with any type of heating equipment apart from mercury vapour lamps, these cannot be thermostatically controlled. Though due to economic factors most keepers reserve the dimming thermostat to the likes of deep heat projectors and halogens and use the less expensive thermostats for the other heating equipment.

Maximum Wattage

Each thermostat comes with a maximum wattage that can be passed through it. Most on off thermostats have a maximum wattage of 100w or more, so a 60w heat mat poses no issues. The pulse and dimming thermostat typically come in 600w. In any case make sure that any heating equipment does not exceed the maximum wattage of the thermostat you choose to use.

What wattage bulb?

It is better to use a lower wattage bulb that when thermostatically controlled, is only slightly dimmed. Remember that reptiles associate high light with good basking sites so it is preferable to use a lower wattage bulb that will occasionally be dimmed that than use a bulb that is of too high a wattage, meaning it has to be dimmed down further, reducing the light output of the bulb. The heat output will remain as infra red heat energy is non visible to the human eye. But its better to have the bulb run closer to maximum output for the maximum output of light.

Probe Placement

To get the right probe placement you will need to have an understanding that the air temperature within a vivarium is likely the same across the whole enclosure and the difference between warm end and cool end temperatures is more accurately under radiation or out of radiation. If you imagine a warm summers day, if you stand in the sun you feel hot, if you step into the shade you cool down. This isnt because the air suddenly drop from stepping one foot to the side. Its because you are no longer under radiation. Consider this analogy when thinking about probe placement.

• Under Radiation - light upon a dark probe will raise its temperature above that of air temperature.

• Out of Radiation - When shielded from lights it will have a true reflection of the air temperature inside the enclosure. If it is not touching another object and is sticking out into the air away from walls, decor etc.

The probe placement can be different depending on who you ask the users preference. One method is to have the probe within or just outside the radiance of the heat source. So, if you have the probe right under the heat source and you set a temperature of 28C then you are going to get a temperature close to or similar to that. You will likely have to use other temperature measuring equipment to calibrate this to your exact requirements. This way the hot end is unlikely exceed the set temperature.

The other method is placing the probe at the cool of the vivarium, then you can set to the warmest cool end temperature required of your chosen species. This means that the user will know that the reptile will always have a cool enough area to go to, to cool down. However, the basking bulbs will likely run at full power and it will take tweaking of bulb wattages and use of monitoring equipment to fine tune the set up. If you can get a wattage of bulb that just about gets to your desired temps then you have the goldilocks zone. Brightest possible basking spot at the temperatures you want.

Running multiple heat products off one stat?

You can run multiple heat mats or bulbs off one thermostat. Again, as long as you don’t go over the maximum wattage of the thermostat. I have ran both of my bearded dragons basking bulbs from one dimming thermostat. Providing that the products are suitable for the type of thermostat you are good to go! Only having to buy one thermostat makes the prospect much more appealing to some keepers.