 at night or when it is unoccupied).The belief is that if the building is allowed to change temperature, its heating or cooling system has to "work harder" to bring it back to a comfortable temperature, counteracting or even exceeding the energy saved during reduced heating or cooling.If set up correctly the setback and recovery feature can result in energy savings of five to fifteen percent as the heat transfer between a structure and its environment is proportional to the temperature difference between the inside and outside of the structure.