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Bio sauna: the gentle version of the sauna
The bio sauna – also called soft sauna or humid warm-air bath – is less hot than a Finnish sauna but more humid. Many people find it more pleasant, especially when starting out.
Updated: September 2026 · independent guide, sources linked
A bio sauna usually needs a combi heater with a vaporiser. What electric and wood-fired heaters offer is shown in our heater comparison.
Wood or electric heater guide →At a glance
| Temperature | usually about 45–60 °C |
|---|---|
| Humidity | approx. 40–55 % |
| Heater | usually an electric combi heater with water vaporiser |
| Other names | soft sauna, humid warm-air bath |
| For comparison | Finnish sauna usually 80–90 °C with dry air |
What makes a bio sauna
A bio sauna runs at lower temperatures than a classic Finnish sauna, usually around 45 to 60 °C. In return the air is more humid, at around 40 to 55 percent. The heat feels softer as a result.
The humidity usually comes from a combi heater: an electric sauna heater with a built-in water tank that vaporises water evenly. Depending on the setting, the same heater can also run the cabin as a classic Finnish sauna.
From dry to wet
- Finnish saunahot and dry, usually 80–90 °C, short bursts of steam when water is thrown – see Finnish sauna.
- Bio saunamedium temperature, medium humidity: about 45–60 °C at 40–55 %.
- Steam roomlower temperature, very humid: around 50 °C at almost 100 % – see steam room.
- Infrared saunamild air temperature, heat by radiation – see infrared sauna.
A bio sauna in your garden
A garden bio sauna usually uses an electric combi heater. That generally means a 400 V connection, a carefully planned power cable and a location not too far from the house. As there's more moisture in the cabin, good ventilation and quality wood matter. Whether barrel sauna or sauna cabin: ask specifically for a combi heater in your quote. Running costs are under cost.
For a sauna in the garden, each canton handles the building permit differently, for example Appenzell Ausserrhoden, Obwalden and Uri. All 26 cantons: Building permit.
A bio sauna usually needs a combi heater with a vaporiser. What electric and wood-fired heaters offer is shown in our heater comparison.
Wood or electric heater guide →More sauna types: Finnish sauna · Smoke sauna · Wood-fired sauna · Electric sauna · Barrel sauna · Sauna cabin · Infrared sauna · Steam room · Kelo sauna · Kota sauna · Mobile sauna
Sweat baths of other cultures: Banya (Eastern Europe) · Roman baths · Hammam · Sweat lodge (North America) · Temazcal (Mesoamerica) · Qargi (Yup'ik & Inuit) · Steppe nomads (Scythians) · Hanjeungmak (Korea) · Mushiburo (Japan) · Sweathouses (Ireland)
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