Determine your heating needs

Calculating the heater size for a reptile cage will depend on several factors, including the size of the cage, the type of reptile, and the temperature requirements of the species.

Here are the general steps you can follow to calculate the heater size for a reptile cage:

1. Determine the size of the cage: Measure the length, width, and height of the cage in feet. Multiply these three dimensions together to calculate the volume of the cage in cubic feet.
2. Determine the temperature requirements of the reptile: Different species of reptiles require different temperatures, so it’s important to research the specific needs of your reptile. There will be 2 main temperatures to account for: ambient (overall cage temperature) and basking (spot heat for warming). As a general rule, most reptiles require a basking area that is at least 10 degrees Fahrenheit warmer than the rest of the cage.
3. Calculate the temperature difference: Subtract the ambient temperature of the room from the desired cage temperature to determine the temperature difference. For example, if the room temperature is 70 degrees Fahrenheit and the cage temperature needs to be 90 degrees Fahrenheit, the temperature difference is 20 degrees Fahrenheit.
4. Calculate the wattage needed: Multiply the volume of the cage in cubic feet (step 1) by the temperature difference (step 3) and by 0.1. This will give you the wattage needed for the heater. For example, if the cage is 2 feet long, 1 foot wide, and 1.5 feet tall (3 cubic feet) and the temperature difference is 20 degrees Fahrenheit, the wattage needed would be 6 watts (3 x 20 x 0.1).
5. Choose the appropriate heater: Once you have calculated the wattage needed, choose a heater that matches or exceeds the calculated wattage. For example, if you calculated that a 6-watt heater is needed, choose a heater that is rated for 6 watts. If the wattage falls between 2 heater sizes, use the higher wattage heater.
   • Additional items to consider: Physical size of your selected heater (moreso with Radiant Heat Panels and/or heat mats) and efficiency. You need to make sure your heater will fit your cage. Most heaters are designed to not run at 100% heat output all the time. In our example of 6 watts, find a heater which can run higher than 6 watts, as a thermostat or rheostat can reduce the output while offering a buffer to allow for more heat in cooler times.
6. All heating elements should be controlled with a rheostat or thermostat (preferred) to ensure the cage does not overheat.
7. If your animal requires a basking hotspot you can use the same calculation, replacing the ambient room temp with the ambient cage temps. You will generally be able to use a heat bulb for a basking spot.

It’s important to note that these calculations are just a general guideline, and you should always consult the specific requirements of your reptile and the recommendations of the manufacturer of the heater you choose.