Plan a sauna in five steps
- Indoor or outdoor. Indoor rooms sit in a heated house and lose less heat; garden cabins and barrels need a stronger heater in winter and a solid base.
- Size for the people, not more. Count about 60 cm of upper bench per person and 190 cm if someone wants to lie down. Every extra cubic metre has to be heated each time.
- Benches. Keep 100–125 cm between the upper bench and the ceiling, so your head sits in the hot air but you can still sit up straight. Two tiers are the norm (bench height guide).
- Heater. Glass, tile and solid wood walls raise the effective volume the heater has to cover. The studio picks a heater whose maker rates it for your room; check the numbers in the heater size calculator.
- Air and power. Fresh air in near the heater, exhaust low on the other side (ventilation guide). Electric heaters need their own circuit (electrical requirements).
What the studio works out for you
- Effective volume with the makers' rule: +1.2 m³ per m² of glass or masonry, ×1.5 for solid log and barrel walls.
- Heat-up time and cost per session from a heat model of the air, walls and stones, with your country's electricity price and climate.
- Fuse or breaker size for the heater on your country's supply (the electrician and the heater manual decide the final install).
- Seats, places to lie down and layout checks: bench height, heater clearances, door swing.
- The heat X-ray: the room's air coloured by temperature from floor to ceiling, minute by minute, including what a ladle of water (löyly) does to the humidity.
Typical inside sizes
| People | Inside size (W × D × H) | Upper bench |
|---|---|---|
| 1–2 | 1.3 × 1.3 × 2.0 m | 2 seats |
| 2–3 | 2.0 × 1.8 × 2.1 m | 3 seats, 1 to lie |
| 3–4 | 2.4 × 2.0 × 2.1 m | 4 seats, 1 to lie |
| 5–6 | 2.4 × 2.2 × 2.1 m, L-bench | 6 seats |
Barrel saunas are measured by diameter and length: a 1.9 m barrel that is 2.4 m long seats four on two facing benches. Compare the two styles in barrel vs cabin.