HEATING WITH STOVES
The second stage in the development of heating technology is distinguished by this, that heating is not done by burning fuel in the center of the room, but in specially built "clay pots", initially very primitive and used for cooking and heating at the same time. Only later, separate furnaces began to be built, for room heating only. They were built of ordinary clay, and the exhaust gases also went directly to the inhabited room; from where they came out through gaps in the walls and the roof. The excavations showed, that such furnaces were used in various countries back in the Stone Age and throughout the centuries that followed. In the further development of heating technology, fireplaces with gas discharge directly to the chimneys were built. These fireplaces, after some design evolution, are still used today as luxurious decorative stoves.

Construction of chimneys in residential houses, as to be supposed, it was initiated in northern Europe in the 15th century, because at that time the first specialists in chimney sweeps - Italians - came to Europe, and then Germany, who practiced chimney sweep all over Europe, as well as in Russia2) until the 18th century,