kachelöfen (masonry heater faced with ceramic tiles)
They are domestic wood-burning heating appliances with an internal firebox made of refractory (heat-resistant) fire bricks, and a system of flues within the stove, made from the same material. The entire stove will contain between one and five tonnes of masonry. A kachelofen (German), kakelugn (Swedish) or kakkelovn (Norwegian) is a type of masonry stove. Kachel means tile, so a kachelofen is a tiled stove. Masonry stove is a generic term that includes stoves without tiles.
A masonry heater (or masonry stove, ceramic stove, tile stove) is a device for warming an interior space through radiant heating, by capturing the heat from periodic burning of fuel (usually wood), and then radiating the heat at a fairly constant temperature for a long period. The technology has existed in different forms, from back into the Neoglacial and Neolithicperiods. Archaeological digs have revealed excavations of ancient inhabitants utilizing hot smoke from fires in their subterranean dwellings, to radiate into the living spaces. These early forms have evolved into modern systems.
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 to retain as much heat as possible from the gases and smoke. The ceramic tile surrounding the kachelofen also acts as insulation to retain heat. Kachelofens were carefully designed so that the minimum amount of heat would escape, only as much as needed to warm the flue to maintain a proper air draught. The firebrick used in kachelofen construction holds 80% more heat than ferrous metals such as cast iron, while its heat conductivity is 1/45 that of iron or steel.[4] A kachelofen is efficient enough to warm a house for up to 6 to 12 hours after the fire has stopped burning.[5] Wikipedia
Here are a few examples of Kachelofen's that I built in Germany, as well as some masonry stoves I built in Canada