The secret of good 'löyly'.

The nature of good "löyly" (sauna vapor/sauna heat) is hard to describe. Essentially, it is determined by the purity, temperature, moisture content of the air contained inside the sauna: as well as its thermal radiation. A suitable temperature for sauna air ranges between 80 and 100 degrees C and the humidity from 40 to 60 g per kg of air. The bathers should be able to vary the humidity to their liking by casting water on the stones heated in or on the sauna oven. The inner surfaces of the oven and the sauna room should produce as even a field of thermal radiation concentrated on the bather's body as possible. The purity of the sauna air is above all a factor contributing to the enjoyment of the bathing experience. The sauna air must not contain any obnoxious extent gaseous impurities, particles, or micro-organisms. The purity of the sauna air is ensured primarily by effective ventilation. Particular attention should be paid to the arrangement of correct ventilation, for the internal size of modern saunas is steadily diminishing. The sensation of experiencing good "löyly" is also affected by the overall condition of the sauna. It should have an agreeable and relaxing effect on the bather.