The pros of wood burning sauna heater:
The stones of the heater may be heated up to a very high temperature;
Very simple operation and construction;
It’s a part of the image of traditional sauna.
The cons of wood burning sauna heater:
It takes a long time for sauna to heat;
More stringent fire safety requirements are applied;
Additionally, you will need a chimney, firewood and to clean the heater.
The operation principle of wood burning sauna heater is very simple – the stones, which were heated with firewood, provide warmth to the room. Often, they are installed in saunas made from logs and in houses. The power of wood burning heater depends on the size of the sauna. The larger the room, the more powerful the heater. How to calculate the capacity of the necessary heater? After calculating the volume of the sauna room, you should add 1.5 – its heat, which is lost due to the opening and closing doors. If there are windows and other uninsulated surfaces, the area of this surface is multiplied by 1.2 and added to the common cubic capacity. We’ve acquired a number, according to which you can choose an appropriate heater for that room. This number should be within the threshold of the indicated capacity of the heater. Properly chosen and stoked sauna heater should heat up the sauna within an hour. Upon choosing wood burning sauna heater, you need to pay attention to a couple of important things: quality, economy, type of furnace (interior or exterior) and quantity of stones.
The service life depend on the quality of wood burning heater. Quality heater – sufficient width of the metal, quality metal and good construction. The wall thickness of the sauna heater should not be less than 5 mm. A heater with thinner walls will burn-out faster and will serve you for a lesser time than a heart of good quality and proper thickness. Not only is the thickness of the metal, but its composition very important. A metal could be very thick, but of low quality; it will burn-out fast. The metal of the heater must be new and of good quality, because old metal will burn-out faster. Furthermore, there is a big chance that you could burn down all of the sauna this way. The service life of the heater also depends on how it is stoked. You need to stoke the sauna heater in such a way that the metal would be red, but not orange.
The larger the quantity of stones in the heater, the higher quality steam will be and the warmth will be maintained for longer, however, you will need to stoke for a longer period of time until the required temperature is reached. In the lower level, the sauna heater’s stones heat up to 550 °C and in the upper level – 350 °C. When you pour water on the stones, which hare heated this way, you create good and plentiful steam. The experts recommend purchasing sauna stones rather than collective them outside. The latter stones are dangerous to use due to the possibility that they may explode from the heat. The stones offered in stored were not impacted by heat and cold, contact with air and their composition is solid rock. You may find various stones for sauna heaters, however, most important is that they would effectively accumulate and transfer heat and would not fracture due to abrupt temperature fluctuations. One of the most popular and most often used stones in saunas is talkochlorite. After purchasing stones for sauna heater, you should not place them anyway you like, but following a certain method. They are placed according to their size – below bigger stones are placed and above – smaller ones. Furthermore, gaps should be left between them for air to circulate better. The furnaces of those sauna heaters, which have stones placed from all of the sides, heat more than of the heaters where stones are placed only on the upper layer of the furnace. This happens, because the heat from the metal furnace is transferred through the stones slower than through air, which is why furnaces do not cool down so well.
The economy of sauna heater depends on its construction. Usually, the most economic heaters are called “Harvia” and “Narvi”. The construction of “Harvia” heater is made in such a way, that the fire in the head of the furnace travels above through the sides of the heater enshrouding stones this way and travel out through the chimney. However, “Nervi” technology is even more effective. From the furnace, the fire travels directly in to two tubes; from all sides stones are placed near them. Such method helps to make the combustion process more effective, reduce the quantity of consumed firewood and reduces air pollution.
When it comes to heater’s guards, you do not need to always make them. If the sauna heater is bricked, then the guard is not needed. However, around the metallic heater it is recommended to make a guard at the 50 cm distance. And around the metallic heater, all of the sides of which are placed with stones, - at the 30 cm distance a guard should be placed.
First-time sauna enthusiasts ask whether the stones of wood burning sauna heater need to be taken care off, whether they need to be washed or replaced. Over time, these stones get covered with lime; it is really recommended to wash them off. It is really not that hard to do. Warm stones need to be immersed in to the citric acid or vinegar solution. Lime will then be easily washed away. At the same time, you can inspect the stones whether they are not crumbling. Crumbling stones should be replaced with new ones; it is best to do this once a year. It is not recommended to wash the stones with scrubbing aids, because the used stones have pores and they will absorb a part of chemical preparations. And when they will be re-used, these chemical particles through steam will end up in to the human body via mucous, eyes and lungs.
Prior to purchasing sauna heater, it is always best to consult with the specialists of this area. They will surely help you to find the best solution, what kind of sauna to install, what kind of heater to purchase and how to use it most effectively.