This was recently posted in the Wood-Burning Sauna Forum on Facebook. I was thankful that he took the time to write this and also chose a Kuuma.
“I have visited saunas around the world. I am finally preparing to build my own at home. There is an old wood plank shed/barn that my wife is letting me take over.
I am an engineer in an industry where we cure 300+ meter long tubes of thermosetting resin. Dry air just will not carry and transfer the heat to cure the pipes. It takes steam… Dry steam, not wet steam. Wet steam condensates too much and cools quickly. Wet steam will also not carry the thermal energy to the far end of the pipe, or to every corner of a larger sauna.
I see the same dynamics inside a sauna. It takes heating up lots of thermal mass with only a little bit of water at a time to make that good “dry” steam. The kind of steam that transfers the heat energy into your body and into the sauna surfaces, rather than just blowing past. And that kind of dry steam doesn’t drip and cool and turn the place into a tepidarium. Tepidariums have their uses at spas, but they do not make for a good sauna experience!
I’ve been pursuing the perfect steam to cure pipes for 30 years. For most of that time, I didn’t apply that engineering to my sauna hopping hobby.
But as I thought about building my own, I looked at electric stoves. I even looked at the science behind infrared panels. The convenience was compelling. The exceptionally deep penetration of IR and studies on tissue detox and healing were quite intriguing.
But ultimately, I am chasing that feeling that I get in the best saunas around the world. And it all goes back to the “dry” steam.
The absolutely dry air heat of an electric sauna that you don’t throw water onto is miserable. The heat transfer to your body just doesn’t penetrate, just as heated dry “air” won’t drive an exotherm in a thermoset pipe.
Even an electric sauna with a small mass of stones that you throw water on is NOT the same. Without the rapid transition from water to “dry” steam, which can ONLY occur with small amounts of water hitting a thermal mass with high energy storage, the sauna at best starts to feel like a tepidarium as people add too much water chasing that dry steam body penetration that just never really happens. Electric heat just is not an efficient way to heat the amount of thermal mass it takes to generate good dry steam.
While I can experience good dry steam in a gas-fired sauna with high thermal mass, for me, the air quality just does not “feel” the same. I enjoy it. I just enjoy the same good dry steam with my preferred air quality from a wood-burning stove far better. For me, wood does moisten the air in good ways; comparatively, gas over dries it and leaves a less pleasant odor. But I get why large sauna spas go with the efficiency and ease of gas firing.
For me, I have decided to go with a wood-burning Kuuma stove. It is built to be able to efficiently heat a very large thermal mass without continuously stoking with more logs during my sauna sessions. The kuuma stove can sustain long sessions of generating good dry steam for the best thermal transfer at every bench and corner. Dry steam will carry, distribute, and transfer the heat more evenly than hot dry air, and more thermal energy will transfer to the sauna surfaces and the bodies faster.
Airflow is critical too. The more molecules of dry steam that can carry and transfer the thermal energy to the sauna surface and to the bodies, the faster they will all rise to the desired temperature. Lack of fresh airflow causes it to take far longer to transfer greater heat energy from the available dry steam.
I will enjoy the ritual of preparing the perfect mix of 2/3rds fire sustaining and 1/3rd very dense slow-burning, but high-energy-releasing wood (such as Oak or Hickory). Cutting & splitting bulk supplies to the perfect size for easy loading into the stove. And mastering the stove fire and the resulting dry steam to the thermal ecstasy of all of my guests.
Yes, IR does penetrate deeply into the organs in a way dry steam never will. But dry steam elicits a “spiritual” reaction from my body in the way no lamp therapy ever will. Especially when the sauna energy is released from burning wood. For me, wood releases spiritual energy that we can feel in the way fossil fuels and electricity simply cannot do.”