In the previous two parts of this article (How to Build a Perfect Sauna and 5 Questions to Ask in Sauna Selection) I described that the Finnish sauna has developed over a very long period of time, and us Finns have it in our DNA. We just know what a good sauna is, but that is difficult to quantify. Also every sauna is different in some way. We at Saunastore design saunas every day, and we consider these in each case. I have listed five of the most important features that you have to remember in creating your perfect sauna.
1. Sauna ventilation
Ventilation is absolutely key to a great sauna in many ways. Ventilation brings new oxygen rich breathing air, without which you will quickly begin feeling drowsy, uneasy, and compelled to leave the sauna. Ventilation can help to even the temperature differences inside the sauna, and dries the sauna after the sauna session. Ventilation can work naturally or forced with a fan. Incoming air channels are just as important as outgoing air vents. The quantity of air changed should be a minimum of c.3 m3/h for each m3 of sauna volume, or at least 22 m3/h in any sauna. A too strong ventilation can drain the hot air out.
2. The sauna heater
The sauna heater is the heart and soul of the sauna, so you should not make a compromise here. The heater is normally an electrical heater, with resistors that heat rocks, onto which water is poured to create the steam. Manufacturers specify the power rating for a specific size sauna, but you can choose one size more powerful without issues, as it will guarantee the sufficient heat and warm up the sauna faster. The quantity of stones is important. A same power heater with a small capacity of stones vs large capacity will heat up the sauna faster, but a larger capacity heater has many benefits. When water is poured, the stored heat within the rocks is used to vaporize it. A large stone capacity suffices for more löyly, steam to be generated. Also a large stone capacity has more rock surface area, and thus there are not only a few very hot rocks but many milder ones. So the steam will be softer. And the heat is dispersed more evenly within the sauna. The trend is towards having more rocks, going from the typical basic wall-hung heater with 20 kg stones to tall floorstanding models with c. 100 kg. The visual design of the heater is certainly important, as it is the focus of attention while relaxing and meditating, watching and listening to the löyly steam.
3. Sauna temperature and humidity
The sauna temperature is a highly subjective issue. First of all the temperature in the sauna varies from lower level to the head level. Also horizontally, when sitting on the upper bench, two persons can sit in different places and experience a different sauna at the same time. Small children may enjoy a milder sauna, when the hardened grandfather wants a really hot one. The Finnish sauna is normally 80-90 degrees C, but a milder one is also ok. The temperature of the sauna should however reach above 65 degrees throughout, because that will kill most bacteria, which would otherwise create an unpleasant smell and not a hygienic experience. Humidity is part of the Finnish sauna, even though the Finnish sauna is a dry sauna. Your skin senses the humidity, you feel it in your breath, and it is very important. As water is poured on the hot stones of the heater, a large quantity of hot vapour is produced that feels stingy for a few moments and then evens out and is eventually ventilated out. It is a key feature of the Finnish sauna to be able to regulate your own löyly (water on the heater) in quantity and frequency. The vapour transmits heat from the heater to you, and the vapour will condensate on your skin. So part of the water on your skin is not perspiration but this condensation.
4. Sauna dimensions and passageways
Contrary to popular belief, a larger sauna is not always better in its quality of bathing. It is a question of correct ventilation and heater size. However, a larger sauna will allow more freedom to plan for creative bench configurations, ample passageways and more safety as a result. A typical home sauna in Finland is c. 230 cm wide and 150 cm deep, ranging from 120×120 to 350×250 cm. Saunas larger than that are found in public establishments. The most important dimension in any sauna is the distance from the ceiling to the upper bench. This should be 110 cm, +/- 5 cm. If the benches are too low, the heat and löyly will be above the bathers heads, and the sauna is not a great sauna. If your sauna is very high, you either need to lower the ceiling, or have high benches. High benches are not a bad thing, but you need multiple steps in order to climb up. A normal sauna inside height is 220 cm and the upper bench is thus 110 cm from the ceiling, and the floor. Typical bench depth is 60 cm, and the distance from lower to upper bench is 40-45 cm. We at Saunastore always design the saunas with a 3D-program, allowing to see the sauna from all angles, checking the passageways, safety distances from the heater, views from the benches of the heater and out the windows, and soforth.
5. Construction quality
Sauna used to be constructed from cheap materials, although with heart and consideration. Now it has become the most meticulously designed and planned room in any house. The owner is proud of his/her sauna, and will gladly display it to guests, or present an invite to guests to take the sauna, which is a great honour. Details of construction are important. There should be no visible nails or screws, as metal is very hot against naked skin in the sauna. The joints and ends of wood should be thoughtfully made. Wood types, colours, orientation should be harmonic. The sauna should not overwhelm the senses with too colorful materials, or with lights for that matter, not to mention music or TV or other distractions. The sauna is a subtle feeling, where you relax and explore your senses. It is like foie gras. Don’t spoil it with ketchup. Present it well, and you will enjoy it more.
So to recap: first consider what your sauna use will be and what you can build. Then design it with a professional, considering 1. The ventilation, 2. The heater, 3. Temperature and humidity, 4. The dimensions and design, 5. Construction quality and materials.
We Finns are passionate about the sauna, which we at Saunastore think should not be a secret of the Finns only. Contact us and we’ll be glad to talk to you about your project and give our advice.