Nope no thermostat on these, the cable reaches 34dgc and mounted above that is a large tile to evenly disperse the heat, in effect i covers approximately 1/3 of the tank. The ambient temp gets to about 27dgc, the cable are on timers so that at midday there off for a few hours. The footprint of the individual enclosures is 800x400 leaving plenty of space to move away from the heat.