an electromechanical thermostat for controlling the on / off cycle of a heating / cooling unit . the thermostat has a temperature sensing element with a variable position according to the sensed temperature . associated with the sensing element is a switch member that provides on / off signals in response to the position of the sensing element . the thermostat has mechanical heat anticipation to control the generation of the on / off signals . in the preferred embodiment the mechanical heat anticipation is accomplished by a stepper motor which varies the position of either the sensing element or switch member to simulate thermal heat anticipation . the thermostat also has a mechanical structure to reduce or eliminate thermostat droop . preferably this structure includes a control circuit to detect the duty cycle of the heating / cooling unit and mechanically and automatically adjusts the thermostat set point .