The temperature is a critical factor in every terrarium and needs to be adjusted to meet the needs of the animals. However, it is not so easy to adjust the proper temperature with all the different heating products available and the heat being produced by the terrarium lighting. A thermostat helps to maintain the desired temperature and prevents the terrarium from overheating. Additional functions like a night time temperature decrease are available in some thermostat models and help to provide optimal conditions to the animals.
A little less common are humidity controls for monitoring and maintaining the humidity inside the terrarium. A lot of animals like the Green Tree Python have very specific humidity requirements which make the use of humidity controls recommendable.