While modern cooking stoves are convenient, when it comes to energy use they leave a lot to be desired. As we have seen in the previous article, the thermal efficiency of an electric hob does not exceed that of a conventional open fire. In both cases almost 90% of the primary energy is lost during the cooking process.
Cooking food could be achieved in a far more energy efficient way, especially if the cooking pot itself is insulated. This is the principle behind the fireless cooker, a well-insulated box that keeps food simmering with only the heat of the cooking pot itself. A fireless cooker doubles the efficiency of any type of cooking device because it shortens the time on the fire and limits heat transfer losses.
In the early twentieth century, fireless cookers were common additions to western kitchens, similar to the refrigerator or cooking stove. Some models even integrated fireless cookers with gas or electric hobs. These functioned by lowering an insulated hood over the cooking pot once the heat had been switched off.