Abstract: A heating device is provided comprising a heating chamber for receiving and storing a substance to be heated having at least two walls, a reaction chamber affixed to a wall of the heating chamber, a solid-state modified thermite reaction composition located within the reaction chamber and an actuatable trigger mechanism affixed to the reaction chamber such that the trigger mechanism is in contact with the reaction composition. According to another aspect, a heating device is provided comprising a heating chamber defining an interior space for receiving and storing a substance to be heated, a reaction chamber, a solid-state modified thermite reaction composition disposed within the reaction chamber such that it is physically isolated from and in thermal communication with the interior space of the heating chamber and an activator mechanism affixed to either reaction chamber or heating chamber such that the activator mechanism is in communication with the reaction composition.