A sauna is a small room or house designed as a place to experience dry or wet heat sessions, or an establishment with one or more of these and auxiliary facilities.
Technologies. Today there are a wide variety of sauna options. Heat sources include wood, electricity, gas and other more unconventional methods such as solar power. There are wet saunas, dry saunas, smoke saunas, steam saunas, and those that work with infrared waves. The Finnish word for a sauna heat source is kiuas. There are also two main types of kiuas: continuously heating and "always on"-type. Continuously heating kiuases have a small heat capacity and can be heated up on an "on-demand" basis, whereas an "always on" kiuas has a large heat capacity and can take up to 24 hours to heat up.
The Finnish sauna is a substantial part of the Finnish culture. There are five million inhabitants and over two million saunas in Finland - an average of one per household. For Finnish people the sauna is a place for easing with friends and family, and a place for physical and mental relaxation. Finns think of saunas not as a luxury, but as a necessity. Before the rise of public health care and nursery facilities, almost all Finnish mothers gave birth in saunas.
As the home of the sauna, Finnish sauna culture is well established. Although cultures in all corners of the world have imported and adapted the sauna, many of the traditional customs have not survived the journey. Today, public perception of saunas, sauna "etiquette" and sauna customs vary hugely from country to country. In many countries sauna going is a recent fashion and attitudes towards saunas are changing, while in others traditions have survived over generations.