Heating the Vivarium: Air and Water Temperatures

terrarium heating

Most reptiles and amphibians are cold-blooded animals.

They depend on external sources of heat to drive their metabolisms and keep their bodies within the proper temperature range. It also means that their habitat must provide a climate that is similar to what they experience in the wild.

Because most rainforest-dwelling herps are from warm regions, you’ll usually need to install some type of heating device to elevate the enclosure’s temperatures. There are a few exceptions, and some tropical reptiles and amphibians will thrive at room temperatures. Crested geckos and poison dart frogs, among others, come to mind.

However, even those who prefer relatively cool temperatures will still benefit from a thermal gradient. And you’ll need a heat source to create a gradient.

Below, we’ll discuss the best ways to provide the proper thermal environment for your pets. We’ll also explain the differences between ambient and surface temperatures, and the best ways to create thermal gradients. Finally, we’ll lay out some of the best methods for monitoring the habitat’s temperatures.

The Differences Between Ambient and Surface Temperatures

Before we begin discussing the nuts and bolts of heating your pet’s habitat, we must draw a distinction between ambient temperatures and surface temperatures. Both are important from a husbandry point of view. And you’ll often need to use two different heat sources to ensure both remain at the proper levels.

Surface temperatures refer to the temperature of rocks, branches, substrates and other objects in the habitat. Ambient temperatures, by contrast, refer to the air temperatures inside the enclosure.

Most reptile care sheets and books are talking about ambient temperatures when they provide temperature recommendations for a given species. But while ambient temperatures are certainly important, it is also important to consider the surface temperatures in the habitat. This is because ambient and surface temperatures often vary greatly.

Consider a rock sitting in the sun on a hot day. The ambient temperatures on such a day may only be in the 90°F range (~32°C). The surface of the rock, however, can easily exceed 130 degrees (~54°C) or more. Some reptiles require surface temperatures in this range for basking. But you certainly wouldn’t want to expose your pet to 130-degree ambient temperatures, as these may prove dangerous.

vivarium thermal gradient

The Importance of a Thermal Gradient

In addition to drawing a distinction between air and surface temperatures, it is important for reptile and amphibian keepers to understand the importance of thermal gradients.

A thermal gradient is nothing more than a range of temperatures. The area nearest the heating device will be quite warm. Accordingly, the temperatures will fall with increasing distance from the heat source.

This is helpful, as it provides your pet with the chance to adjust his body temperature by moving closer to or farther from the heat source. This is preferable to forcing him to live at an arbitrary temperature in a uniformly heated habitat.

The best way to establish a thermal gradient is by positioning the heating device(s) at one end of the enclosure. Ideally, you should do so in a way that maximizes the distance your pet can retreat from the light.

This will provide the greatest amount of temperature differential between the hottest part of the enclosure and the coldest.

It is even possible to create gradients along the vertical axis of the habitat, but this is generally more difficult than establishing a horizontal gradient.

In any case, you’ll want to be sure to provide a gradient that works well for your pet’s behavioral pattern. For example, lizards that frequently climb trees to thermoregulate may adapt well to a vertically oriented thermal gradient. On the other hand, a vertical gradient would be worthless to a box turtle.

Heating the Vivarium

There are a number of different ways to heat a reptile or amphibian habitat.

Typically, you’ll need to provide a basking spot that provides relatively warm surface temperatures. If the habitat is relatively small, the heat source for the basking spot may be all you need to keep the ambient temperatures at the proper levels. But very large habitats (or those that require very warm ambient temperatures) will often force you to implement multiple sources.

Reflector Domes

Reflector domes fitted with incandescent bulbs are perhaps the most popular choice among reptile keepers. They are easy to use, inexpensive and mimic the sun in some ways.

However, you can also use reflector domes with ceramic heat emitters, which do not produce light. If you choose to use these, you’ll have to illuminate the habitat with fluorescent lights. Fluorescent lights produce very little heat – they are primarily useful for lighting habitats, not heating them. However, ceramic heat emitters can be used at night, without disrupting your pet’s day-night cycle.

vivarium heating

Radiant Heat Panels

Radiant heat panels are also a great option for heating reptile and amphibian habitats. These produce no light, so alternative lighting will be required, but they are fantastic heating devices. They can provide very safe and consistent heat. Radiant heat panels must, however, be used in conjunction with a thermostat (more on thermostats below).

Ceramic heat emitters, reflector domes and radiant heat panels are best used to create a basking spot. But you can use multiple devices to help raise the ambient temperatures.

However, it is often more helpful to use heating devices that heat the enclosure from below to raise the ambient temperatures.

Heat Pads, Heat Tape and Heat Cables

Heat pads, heat tape and heat cables are all viable ways of heating a habitat from below. They all require thermostats to ensure their temperatures remain at the appropriate levels.

It is always important to provide an air space around the under-tank heating devices. It helps to prevent heat from building up to dangerous levels. This can be difficult with large or heavy enclosures, but fire safety should always remain at the front of your mind. No matter what types of heating devices you use, be sure to monitor them regularly and keep combustible materials away from them.

Providing Suitable Water Temperatures

If you build a large water feature for the habitat, and your pets spend a lot of time soaking or swimming in the water, you’ll want to ensure that the water is also suitably warm. This doesn’t mean that it is always necessary to use a heater to do so. Often, the ambient temperatures in the habitat will be sufficient to keep the water suitably warm.

However, it will be necessary in some cases to use a heater for the water. Be sure to familiarize yourself with the proper water temperature for your pets. If no such data is available, water temperatures in the high 60s to low 70s Fahrenheit (~16 to 21°C) serve as a good starting point.

Thermal gradients aren’t usually important for water features. This is fortunate, as the water will quickly develop a uniform temperature. Particularly if you employ any type of filter or pump that circulates the water. It would ultimately prove quite challenging to do so in most rainforest vivaria.

There are two primary ways by which you can heat the water in your pet’s habitat. You can use a submersible aquarium heater or place heat tape (or a heating pad) under the water feature (outside the habitat). Either method will work, and both methods present different benefits and drawbacks.

heating the water

Submersible Aquarium Heater

A submersible aquarium heater provides the most direct way to heat the water in the tank. And little heat will be wasted in the process. Submersible aquarium heaters are designed specifically for this task, and most come with a built-in thermostat. This makes it easier to keep the water at the desired temperature. And you needn’t use an external thermostat or spend hours trying to determine the amount of heat tape necessary.

However, submersible heaters must typically be placed “out in the open”. This can ruin the aesthetics of the habitat and it also places your animals at risk. They may be burned if they come into contact with the heater. They also may suffer shocks if they damage the heater (which can also put you in danger of being shocked).

Heat Tape and Heating Pad

Alternatively, a heating pad or length of heat tape can be installed beneath the habitat and placed under the water reservoir. The heating element will heat up the bottom of the habitat, which will, in turn, heat up the substrate (if present) and water. This requires more electricity, as much of the device’s power will go into heating things other than the water. Also, heating pads or heat tape must be used in conjunction with a thermostat to keep the temperature at the appropriate level.

You will, however, still need to provide an air space around the heating pad. This will prevent dangerous amounts of heat from building up, as you must whenever placing a heating device in any enclosed space.

heating control

Controlling and Maintaining the Habitat Temperatures

Obviously, you can’t pump unlimited amounts of heat into the habitat, as this will push the temperatures above the desired range. But on the other hand, you must provide enough heat to ensure your animals can remain active and healthy. This means that you must monitor the temperatures in the habitat and take steps to keep them at the proper levels.

To monitor the temperatures in the vivarium, you’ll need the two different following tools.

Non-contact Infrared Thermometer

A non-contact infrared thermometer is a handheld device that reads the surface temperature of items in the tank. This makes it good for monitoring the basking spot, as well as verifying that there are no hot surfaces in the habitat.

Indoor/Outdoor Thermometer

An indoor/outdoor thermometer is good for measuring the ambient temperatures inside the vivarium. Most units come with an attached probe, which can be used to monitor the temperature of the water reservoir if necessary. Alternatively, if you have no need to monitor the water temperature, you could place the probe inside the habitat, while keeping the display outside, and thus out-of-sight.

When you first establish the habitat, you’ll need to check the temperatures several times each day. However, once you learn how the habitat heats up and cools off over time, you can usually get away with only checking the temperatures once per day.

To help ensure that temperatures remain at the proper levels, you can use a thermostat with some heating devices. A thermostat will turn the heating element on and off to help raise or lower the temperature as necessary. This can be very convenient, but it is not feasible to use a thermostat with heat lamps. Doing so would create quite a disco-like effect in your habitat.

Thermostats work quite well with heat tape, heat pads, heat cables, ceramic heaters and radiant heat panels. You may also want to hook up light-emitting heat devices to a lamp timer, to automate your pet’s day-night cycle. Note that this will cause the temperatures to fall at night, but this is generally desirable when maintaining most reptiles and amphibians. Just be sure to monitor the temperatures at night as you would the daytime temperatures, to ensure the health of your pets.

Let us know what is your favorite way of heating your vivarium in the comments! And don’t forget, if you found this article helpful, go ahead and share it with your reptile- and amphibian-keeping friends.

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Ben Team

Ben Team

Ben is a life-long environmental educator who writes about the natural world. He’s kept and bred a diverse array of reptiles and amphibians over the last three decades, but he’s always been particularly fond of snakes in the genus Morelia and monitor lizards. He lives in Atlanta, Georgia with his beautiful wife and spoiled-rotten Rottweiler.

2 thoughts on “Heating the Vivarium: Air and Water Temperatures”

  1. Your water, pools and relative humidity link in the rainforest terrarium article goes to the lighting article. As a web designer, I was frustrated that I couldn’t find the page with your limited menu selections and no site search option. Your site looks great and is very informative – developing your menu a little more and including a site search would be worth your while!

    I did eventually find the page by guessing the url (replacing /lighting/ with /water/). It was incorrect, but a search option appeared allowing me to find the page.

    Thanks for taking the time to provide information us newbies need!!!

    1. Hi Michelle,

      Thanks for the heads-up, that’s very helpful! I updated the link and added a search option in the footer.

      In a near future, I’ll add a sidebar with the search bar at the top. I’ll also think about a more detailed menu 🙂

      I’m glad you like the website and that the information was helpful to you. Soon, the articles will be edited with product recommendations to help you guys pick the good gears.

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