Tips for Choosing A Thermostat for Your Reptile Enclosure

Since our beloved reptile and amphibian friends (aka herpetofauna, or “herps”) don’t come with their own, internal thermostat, it’s important to make sure your enclosure is set up with the necessary equipment to help your pet regulate its body heat.

Heat control isn’t simply for comfort—our cold-blooded herps use heat for biological processes like digestion, respiration, reproduction, and maintaining their immune response to defend against infection.

Choosing a proper thermostat takes a bit of time and research, and begins with understanding your reptile’s unique heat and humidity requirements, enclosure size, and setting up the habitat so there’s a temperature gradient (a cool side and a warm side). All together, this allows your herp to have more control over its own body temperature: Raising it by moving toward the heat source / basking, and lowering its temp by relaxing under a hide on the cool side when the animal wants, for example.

Aside from maintaining accurate temperatures specific to the species living in your terrarium, another reason to include a thermostat in your cage set up is to minimize the risk of fire damage and burns.

Types of thermostats

Typically, a thermostat senses the temperature within an area and controls the heater accordingly, so your reptile can enjoy its preferred habitat temps without  overheating from heat spikes. 

There are three types of thermostats that are most useful to reptile keepers: Simple on/off, pulse proportional, or dimming proportional.

On/Off Thermostats:

Simple on/off thermostats will simply turn off the heating device when the temperature you’ve set is exceeded, and then it will turn the heater back on when the temperature has dropped below your set temperature. 

On/off thermostats are popular because they’re usually more cost-friendly, however, they can cause more significant temperature swings in your animal’s enclosure due to completely shutting off the heat source. This also causes stress to the heat lamp filament, often reducing the bulb’s lifespan drastically in the process. As such, on/off thermostats should only be used with low-wattage heat mats (Ultratherm under tank heaters) or other low-output devices.

Dimming Thermostats:

With these, you can more closely manage the heat supplied to your terrarium because they directly increase or decrease the amount of electricity flowing to a bulb, thus increasing or decreasing its light and heat output (rather than simply turning the power source on or off). 

Dimming thermostats are more energy efficient compared to on/off thermostats, they reduce temperature swings, and they cause little stress to the bulb filament, while providing temperature precision.

Dimming thermostats are the best option to be used with incandescent heat lamps (bulbs that emit light) and deep heat projectors. They can be used in conjunction with ceramic heat emitters, heat tape, and heat pads, as well. 

Please note: Dimming proportional thermostats should not be used with lighting that contains a ballast, such as mercury vapor, fluorescent, or compact fluorescent bulbs. 

Pulse proportional:

These work by turning power on to the heating device in small pulses, so the longer the pulse, the more heat generated. Pulse proportional thermostats provide highly accurate temperature regulation and efficient power usage. Since they avoid abrupt on/off cycles and provide precise control over the heat output, pulse proportional thermostats are the least likely to cause thermal stress on connected bulbs, making them suitable for heat and basking bulbs in addition to most heating devices on the market. 

Because pulse proportional thermostats are the most sophisticated, they are often more expensive than other types of thermostats. However, the cost evens out over time due to saving money from replacing bulbs less often.

While it isn't a thermostat, another popular tool used to manage heating devices is the rheostat.


A rheostat is basically a dimmer. It allows you to manually reduce the amount of power reaching a heating or lighting device. You have to manually decrease the heat and/or light output of your device via a dimming dial, and the settings are usually low, medium, or high.

Please note, a rheostat is not a thermostat and does not provide precise temperatures.

A few considerations when purchasing a thermostat

  • How many heating elements do you need to control?
    • Each heating device generally should be on its own thermostat. This is important especially if using two or more devices that 'heat' with different amounts of power. That said, it’s okay to do when you’re confident the different wattages and heater positioning work for 2+ devices to one thermostat.
  • What type of heating devices are you using? 
    • Incandescent bulbs and deep heat projectors should be regulated with dimming thermostats like the Spyder Robotics Herpstat 2. It’s well worth the extra cost for your thermostat as it saves money in the long run from fewer bulb replacements.
    • Dimmable bulbs need dimming thermostats: Halogens and basking bulbs need dimming thermostats (or a dimmer in conjunction with a thermostat), because 1) these bulbs will flicker with other types of thermostats, and 2) they get hotter than normal bulbs so they need extra help to stay in safe temperature range.
  • Check the wattage output of your heating device(s).
    • Make sure your thermostat supports the power output of your device. Some heaters, like radiant heat panels and under tank heaters, use little power (for example, 32 watts). And other heaters like CHEs can use up to 250 watts. This is especially important to note when managing more than one heater with your thermostat.

Rest assured, Bean Farm only chooses to stock thermostats specifically known for being quality-made, reliable, safe, and as accurate as possible. Alternative thermostats found on Amazon are not preferred because they either lack fail-safes, burn out quickly and have to be replaced, or are not made to include proper safety features (for example, thermostats made for seed germination like Inkbird, BN Link, or similar).