Disclosed is a temperature controller device comprising a temperature sensor configured to obtain a first temperature reading within an enclosed area; an air intake sensor configured to derive a second temperature reading outside the enclosed area; a timer configured to measure an operating time of the temperature controller device; an input module configured to obtain a desired temperature and/or a setback duration; a processor operable to calculate: (i.) a first thermal load rate based on the first temperature and second temperature reading, and the operating time of the temperature controller device, and (ii.) a setback temperature; wherein the setback temperature is a function of the first thermal load rate, the setback duration, and the desired temperature. A method and system for determining a setback temperature associated with the temperature controller device are also disclosed.