What to consider when buying an outdoor sauna?
This is especially important in the case of wood. The wood inside the sauna needs to have proper parameters as it has to withstand constant exposure to high temperature, and in the case of wet or steam sauna, also the exposure to humidity.
Choice of wood
First of all sauna has to be made of certified and well tested wood of certain species. Scandinavian species prove to be the best choice, for instance Scandinavian spruce, Scandinavian poplar, Canadian fir (its wood is one of the hardest among the conifer trees around the world), Canadian cedar. Since the mentioned trees grow in such tough weather conditions, they need to have a “strong character”.
What is more all the named types of trees also meet the purity demand. It means that sauna wood cannot have natural flaws such as too many knots (in some cases a large number of the knots is actually an advantage, for instance the Scandinavian spruce has deeply ingrown little knots which give it kind of a “freckled” look). Linden tree wood also qualifies here.
What matters here is the type of wood used. Abachi / African Samba wood bunks are the safest investment. Those are species which do not contain much resin and are resistant to volatile external conditions (heating to high temperatures, air humidity).
Currently in most cases wood burning furnaces are installed in outdoor saunas. However, no matter whether the furnace is fuelled by wood, or uses electricity, it should have all the necessary certificates, and its power should be adjusted to the sauna’s size. The heater’s power is calculated based on the cabin’s size according to the following rule: 1m3 needs about 1kW power. We always have to choose the device with the highest power which fits the heater’s size. Choosing a furnace with too little power will considerably extend the time of highest power operation and thus negatively influence the durability. When buying a furnace we should not only consider the initial price, but also the maintenance costs which we will have to bear.
No matter what type of heater you choose, remember about buying a proper filling. Granite stones are best for this purpose, they heat up quickly and instantaneously evaporate the water – with their help you will fill entire cabin with steam in no time.
The ventilation should allow for air flow in the lower parts of the sauna. That is where the used-up air should leave the cabin and the fresh air enter from outside. The cold air heats up by the floor and ascends reaching the people using the sauna. For keeping ventilation at its optimum it is important to properly use towels. They should be placed on the place we are sitting, but never cover unnecessary space on the bench. Owing to that the air circulation will not be interrupted and the sweat will not soak into the wood.
Measuring temperature and humidity
Depending on the type of sauna the optimal level of temperature and humidity inside will differ. For constant monitoring of those values and achieving the expected therapeutic effect it is necessary to equip the sauna with a precise thermometer and hygrometer – a device which measures air humidity.