Masonry oven India, tandoors are traditional clay ovens, although these days modern electrically fired tandoors are available. The open-topped tandoor is a transitional design between the earth oven and the Roman-plan masonry oven. In the precolumbian Americas, similar ovens were often made of clay or adobe and are now referred to by the Spanish term "horno" (meaning "oven"). Horns are also traditional in the American Southwest. The traditional direct-fired masonry design is often called a "Roman" or "black" oven and dates in Western culture to at least the Roman Republic. It is known as a black oven because the fire generates soot
Masonry heater eastern Europe to modify these efficient heaters so that they are connected to the gas network and are fueled with gas. Some modern models incorporate electric heating elements connected to timers. These are used only as a backup heat source during periods when the structure will be left unattended for long duration in winter (and therefore with no one to build a new fire in the heater each day or as needed) to prevent the structure from freezing. Some contemporary masonry heaters don't have a ceramic-tile exterior. Instead, the refractory bricks are covered by a heat-resistant kind of plaster. A