Definition

As often mentioned, Sauna is the only Finnish word in English dictionary. The definition of sauna means a specific room heated to about 150 to 195 (F) degrees, and where the temperature and humidity of the room can be controlled with sprinkling water on the rocks in the heater/stove. The traditional (Finnish) sauna is still often defined to mean a “dry” sauna – when comparing it to a Turkish-style steam bath. The average relative humidity level in a traditional sauna varies from as low as 10% (if no water is added) to 60%, or more—depending upon how much steam the user likes and how hot the sauna temperature is.

“Sweat Bathing” is a kind of general definition for various types of original bathing in high temperatures – “Sauna” being one of them. Sweat bathing originated with native populations in Europe, Northern Asia and North and South America—with each of them developing separately and with their own unique characteristics. Although the Finns were not the only ones inventing the sweat bathing, they were the ones developing this 2000 years old tradition to what is considered to be the (traditional) sauna nowadays. Thus, today—worldwide—when one mentions the word “sauna”, people most often associate it with the Traditional Finnish Sauna. This is the sauna loved and promoted by the American Sauna Society—and the larger worldwide organization, the International Sauna Society.

The most commonly found sweat baths today are:

Wood Burning Sauna
The wood burning sauna is the closest to the ancient Finnish saunas—a simple, natural experience where wood is used to heat the sauna rocks and the sauna room. The majority of the stoves used in these are continuously heated stoves, in which the wood is being burned in the stove during the sauna bathing. Although wood burning saunas can achieve quite high temperatures—if desired, the user can create the desired temperature by the controlling the rate of burn in the stove. Wood-burning stoves are commercially available, and today’s stoves are very efficient and care-free.
Sherwood4

Electrically Heated Sauna
Available since the 1950s, the vast majority of today’s saunas use electric sauna heaters. In many sauna installations, the only feasible sauna heater type is quite often an electric heater. New wall- or floor-mounted electric heaters are efficient, stylish, safe, and easy to use, and offer a superb sauna experience. They often include remote controls with temperature displays and timers. All major sauna companies have heaters available for all sauna sizes.

Manufactured Sauna Rooms
Electrically heated sauna rooms (also sauna rooms with wood-burning heaters) are available both as free-standing modular units, and as pre-cut lumber kits. The lumber materials most often used include Western Red Cedar, Nordic White Spruce, Aspen, Alder, Hemlock, and Pine.
inside sauna
Smoke Sauna
Smoke sauna (“Savu Sauna” in Finnish language) is a more rare sauna type, with a big wood-burning stove – without a chimney. The sauna “heater” consists of a massive amounts of rocks (several hundreds of pounds of rocks) and is heated up for several hours before the bathers will be able to use it. The smoke and flames from the burning wood heat the rock mass directly, and the smoke enters the sauna room from between the rocks. After the heating phase has been completed, and the flame is out, the room is ventilated, and the sauna is ready to be used. A good smoke sauna offers a very genuine and smooth experience, but as described, the procedure is time-consuming, and requires special circumstances. Smoke sauna kits are not commercially available in the US.

Steam Room
A Steam Room is not a sauna, but rather a Turkish-style Bath. In comparison to the traditional sauna, the humidity level in a steam bath is 100%. The Steam Room enclosure is made of a waterproof material such as ceramic tile, glass, stone or acrylic. The temperature in a Steam Bath is much lower than in sauna (110 to 120 degrees F)—but at maximum humidity. Many sauna manufacturers and dealer also sell steam rooms, and steam generators.

Infrared Room
Not a traditional Finnish sauna; maybe the best definition would be a “heat therapy room”. Infrared heat therapy rooms are based on radiant heat, where the heating elements or emitters reflect the heat directly to the person’s body—rather than heating the air, or stones. There is no water (no steam) used in the infrared rooms. An infrared room is best used as an prior-sports muscle pre-heat means, or after the sports or exercise to relax the tension in the muscles. Several sauna manufacturers sell infrared rooms in addition to steam rooms and traditional Finnish Saunas.

In addition to those mentioned above, the other types of sweat baths include the Roman balneae and thermae, the Turkish hammam, the North American natives' sweat lodge, the temascal in Mexico and Guatemala, the Japanese hot water baths sentoo and o-furo and the Russian bania.