These stoves bristle with efficiency — they are soapstone stoves from the Finish company Tulikivi. They use radiant heat to warm up your house, which is a highly desirable type of heat — it's even and non-drying. It passes through the air in the room, and warms all of the solid surfaces in the room that it "shines" on. Soapstone is used to build these stoves because holds heat very well, and releases it gradually. Unlike wood-burning stoves, the Tulikivi is not finicky. Any seasoned wood will burn well. In Finland these fireplaces are burned with soft woods like pine and birch.The stoves are also very effective at burning wood. Because the fire burns so hot, the wood is totally vaporized. There are no ash, creosote, smoke, or charcoal byproducts left behind, only mineral content from the wood. The fumes emitted by the Tulikivi fireplaces are below the requirements of the German DIN 18891 norm (also Washington state and Colorado state), but the efficiency level is higher than stipulated. The nitrogen content of wood is approx. 0.05%. The smoke gases therefore only contain tiny quantities of nitrogen oxide. The sulfur content of wood is also minimal.
In terms of price, you're looking at a range of $4000 to $15000. Distributors can be found on the Tulikivi web site.