A dimmerstat is a great tool for the ultimate in temperature control. This device will regulate the desired temperature you set. It will slowly increase or decrease the power supplied to your heating device rather than turning it on and off. Due to this functionality they are extremely consistent with the temperature and normally can hold it within 0.2 of a deg c. This unit has a day/night temperature setting as well as a timer for lights/fan where you can set 4 different time intervals. We have been using these particular units for many years and we back them fully.
They are perfect for use on lights and heat projectors to help preserve the life of the bulbs. Then due to the fact it is not an on and off thermostat, you don't stress you animals as if they were at a disco.