Masonry oven more common as accessory features of a masonry heater. A compromise design known as the gueulard in France combines aspects of both internal and external-fired models. Masonry ovens remain popular in part because of the way their use affects cooking processes and food flavor. Where modern gas or electric ovens cook food by moving hot air around inside an insulated, lightweight box, a masonry oven works by soaking up heat, like a battery building up a full charge. When hot, the heavy oven walls release the heat slowly, for hours. Thus the food is cooked not only by hot air,
Masonry heater day and night. Because the radiant heat is given off at a low level a masonry heater is not likely to overheat a home the way a metal stove might in warmer parts of the year like fall or spring. The kachelofen design, a relatively large home heater surrounded with ceramic tile, has existed for at least five centuries. During the Renaissance period, the builders of kachelofens were part of a distinct trade and were called "hafnermeister". A kachelofen uses a maze-like passage created out of firebrick to release gases and smoke from the wood fire slowly, allowing the firebrick