There was smoke in the room when the stove was being heated, but afterwards it vanished, leaving behind a smoky smell. The smoke sauna, with some modern adaptations, is nowadays becoming quite popular again. Today the Finnish word sauna may refer to a building or just a room with wooden walls, floor and ceiling. There is a stove, called kiuas , which is heated with wood, electricity, oil or gas. The top of the stove is covered with a thick layer of natural stones, which radiate the heat to the room.
Humidity is regulated by small doses of water ladled repeatedly onto the kiuas stones.
In due course a dressing room and a washing room were added to the original one-roomed sauna. Sauna suites, frequently used by business people for entertaining guests, may include other additions such as a sitting room with a fireplace. A small private summer sauna often consists only of the hot room and the dressing room. During the last 50 years, the number of saunas in Finland has grown threefold, from about half a million in 1938 to about 1.5 million in 1990. For a total population of just 5 million this is a numerical world record of its kind.