THE HEIGHT OF LAUDE|
There is a common misunderstanding, a common instruction, "the law of löyly," that says that the lower laude must be above the stones of the stove. This is to ensure enough warmth for the legs. Mostly this leads to a good result, but not because of the legs being above the stones level, but because it brings the laude high up. As noted before, the hot air rises directly up to the ceiling. It does not spread out horizontally, as the instructions let us incorrectly think.
If the stove should be low, the barrel-stove could not be one of the best stoves -- or could it?
This instruction does not ensure a good löyly, if the sauna is high and the stove in a hollow below the floor level. The elevation of the stove is of no importance.
It is the distance between the laude and the ceiling that counts.
The height of the laude must be measured down from the ceiling, not up from the floor. The temperature in the sauna comes down as the distance from the ceiling extends. The proper distance from the ceiling is 100-110 cm, max. 120 cm (or 3.5-4 feet), no more. If the distance is more, the energy consumption of the sauna increases significantly, because over the bathers heads is a layer of the hottest air worth nothing. This layer can also be a threat to fire safety, because the sauna must be heated up hotter in order to get the laude level warm enough.
To get the correct distance between laude and the ceiling there must be an additional step to the laude or the ceiling must be lowered to 200-210 cm from the floor, which is a better solution in family sauna, because the alternative additional step takes pace.
In some instructions for larger saunas there is a recommendation to have a longer, up to 150 cm distance between the ceiling and the laude, in order to get more air volume. This is nonsense. There is no reason for additional distance; it would increase the energy consumption and also lessen the quality of löyly.
For instance in a sauna of 15 square meters, the distance of 150 cm between the laude and the ceiling means 5 cubic meters volume worth nothing but a waste and a nuisance. Because the steam rises to the ceiling, this useless space is filled up first and only thereafter comes the löyly down to the bathers. To fill up this 5 cbm space one must steam up almost 3 litres of water. It takes about 2,500 kJ energy to steam up one litre of 50 º C water.
The cost of this 30-40 cm extra distance is best understood if we think that we would need to heat up a sauna so hot, that the second laude would be as hot as the uppermost laude normally. For the bathers this extra distance means that the löyly-master, the person who throws löyly, does not get löyly, which goes over his head to the corner opposite the stove. By sitting close the stove one can throw löyly almost without bounds and terrorise other bathers who are sitting far away from the stove and getting all the löyly.
Even in a large sauna the 120 cm distance is enough, because a sensible and correctly fitted ventilation is always enough. Extra cubic meters of air mean only a delay for the air to come to the bathers.
Another argument for the excess distance between the laude and the ceiling is that a tall person may hit his head to the ceiling when coming up the laude. This may seem to be possible on the drawing board but, in a sauna, no-one climbing up to the laude, stretches oneself to stand in attention before sitting down.
© Saunasite, 1997