A reliable conveyor oven minmizes escape of heat by minimizing the time that inlet and outlet openings appear in the baking oven. This may reduce energy consumption by 25%. The baking oven may have a conventional oven and an extension chamber, an outlet opening of the conventional oven acting as an inlet to the extension chamber, the extension chamber having an exit door, the baking oven also having an entrance door defining an entrance inlet. A conveyor holding food items runs through a length of the baking oven. An exit optical sensor may be attached to the extension chamber on opposite sides of the extension chamber such that an item on the conveyor moving through the extension chamber interrupts a signal between the transmitted and the receiver. The exit sensor may be operatively engaged to a controller for actuating the exit door open and closed rotationally using a pneumatic piston.