Also called Masonry Heaters, they can heat up spaces with a minimum use of fuel (usually wood) as most of the heat is stored in brick.

Masonry Heater

see entry in Wikipedia

masonry heater (or masonry stoveceramic stovetile 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 Neolithic periods. 

Archeological 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. Evidence found from 5,000 B.C. of massive blocks of masonry used to retain heat foreshadowed early forms of fire hearths that were used as multifunctional heating sources. 

Later evolutions came in the Roman hypocaust, Austrian/German (kachelofenbaths) using the smoke and exhaust of a single fire. In Eastern and Northern Europe and North Asia, these kachelofens (or steinofens) evolved in many different forms and names: for example the Russian Stove/Fireplace (RussianРусская печь), the Finnish Stove (in Finnish: pystyuuni or kaakeliuuni, "tile oven") and the Swedish Stove (in Swedish: kakelugn, "tile stove" or "contra-flow stove") associated with Carl Johan Cronstedt. The Chinese developed the same principle into their Kang bed-stove
The masonry heater has gained renewed domestic popularity recently because of its heating efficiency.

continue reading in Wikipedia

The Kacheloven

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 hafnermeisters
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.   A kachelofen is efficient enough to warm a house for up to 6 to 12 hours after the fire has stopped burning.

Traditional kachelofen in Casa Taraneasca, Romania.  Courtesy of Asta Jankune

YouTube Video

YouTube Video