Stove for Continuous Heating
In the smoke sauna and the chimney type sauna the heating flames go directly through the stones. Consequently bathing can start only after the fire has died out.
In the 1930s yet another type of stove was invented: it has a chimney but the fire is isolated from the stones. They are in a metal casing above the fire and there are cast iron elements between the stones to convey the heat to them. The fire is kept burning continuously while the sauna is being used. The intensity of the fire regulates the temperature of the stones and of the whole room. With this kind of stove bathing can often begin in only about 30 minutes. On the other hand the fire has to be continuously attended to , which may be a disturbance, and for many people the quality of the löyly does not equal that of the directly heated sauna, let alone the smoke sauna.
However, the practicality of this kind of stove has made it the most popular wood heated stove in Finland.