This insert is three years old. I regret buying it as the ancient unit it replaced actually heated better. The only advantage I have realized is that the automatic thermostat turns off the blower in the middle of the night. It takes forever for the blower to turn on. I have tried using differing amounts of wood, placed toward the back, the front, with no ash, lots of ash. I don't notice any difference. Does anyone know where the sensor is located? Do you think it could modified to act at a lower temperature?