FAQ: Heating & Lighting for reptiles

A ceramic heater mainly warms the air and surfaces around it, while deep infrared heaters emit longer-wave heat that penetrates deeper into tissue, much like the sun. Neither gives light and both must be run through a thermostat.

It is a heater that emits infrared rays which warm the reptile’s body more deeply, much like the sun’s heat. It gives off very little visible light, so it can be used both during the day alongside other lamps and at night.

Red infrared bulbs do heat, but they also give off visible red light that can disturb the reptile’s rest at night. They can be used during the day, but for night heating a heater that gives no light at all is a better fit.

A heat mat warms the terrarium floor or a wall from below or the side and creates a warm zone where the reptile can warm its belly. It is often used for geckos and snakes, but for diurnal lizards it does not replace a basking lamp.

A mat is usually stuck to the outside of a glass terrarium’s floor or back wall rather than inside, so the reptile cannot damage it or touch it directly. Always follow the manufacturer’s instructions, as some mats must not be fixed under wood or a thick substrate.

A mat should usually cover about a third of the terrarium floor or less, leaving a cooler zone the reptile can retreat to. A mat that is too large warms the whole floor and removes the temperature gradient.

Yes, without a thermostat the mat surface can reach a temperature that burns the reptile’s belly, especially if it lies on it for long. The thermostat probe is placed between the mat and the substrate or on the surface where the animal lies.

Substrate that is too thick traps heat, so the mat may overheat while the reptile feels little warmth at the surface. A thin substrate layer is usually left over the mat, and for burrowing species the mat is more often fixed to a side wall.

In wooden terrariums a mat under the floor often heats poorly because wood is an insulator, and the mat may overheat. In that case it is fixed inside on a wall or the floor as the manufacturer instructs, covered and always controlled by a thermostat.

In nature diurnal lizards bask in the sun from above, so they need light and heat from overhead. A mat only warms the belly and does not create a bright basking spot, so it can only play a supporting role.

A heat cable is a flexible wire that can be laid under the terrarium floor or on a wall in any shape. It is handy for irregularly shaped terrariums or for heating several terrariums on a rack, and like a mat it must be run through a thermostat.

Some cables are made for use in damp substrate, but most must only be fixed outside. A buried cable can overheat and the reptile may dig it up and damage it, so always check whether the manufacturer allows this use.

Heat rocks are often criticised because their surface can heat unevenly and too much, and reptiles may not sense a burn in time and lie on them for long. Heating from above with a lamp is safer, and if a rock is used it must be controlled by a thermostat.

The most common are on/off, dimming and pulse-proportional thermostats. On/off models suit heaters that give no light, dimming models suit basking lamps, and pulse models suit ceramic heaters and heat mats.

An on/off thermostat keeps switching the lamp on and off, so the light flickers in the terrarium and the bulb burns out sooner. A dimming thermostat lowers power gradually, so light and temperature change smoothly.

A pulse-proportional thermostat feeds the heater power in short pulses and holds the set temperature very precisely. It suits heaters that give no light, such as ceramic heaters, mats or cables.

The probe goes where you want to control the temperature: in the basking zone under a basking lamp, or on the surface above a heat mat. Fix it so the reptile cannot move it, because a displaced probe can make the heater overheat the terrarium.

It can if the thermostat allows the combined wattage and the heaters serve the same zone, but it is usually more convenient to give each heater its own thermostat. Then the basking lamp, mat and night heater are each controlled by the temperature of a different spot.

Such a thermostat lets you set different temperatures for day and night, so the terrarium automatically cools to a suitable level for the species at night. It is handy when a night heater runs around the clock but needs to hold a lower temperature at night.

Every thermostat has a stated maximum load in watts that must not be exceeded, or it can overheat and fail. Before connecting several heaters, add up their wattages and leave some margin.