A sauna built for 90 °C inside and 90% humidity outside

Sizes that map to real venues

The sizing rule we never break: about 1 kW of heater per cubic metre of cabin, then round up for glass. An under-heatered sauna in the tropics never reaches temperature on a humid evening - it is the most common flaw we see in existing builds we are called to fix. The full logic is in the sauna sizing guide.

What the cabin is made of

Interiors: knot-free western red cedar (imported) or low-resin local mahogany for benches - woods that stay comfortable at 90 °C skin contact. Structure: twin-shell ventilated walls with foil vapour barrier, so the outside humidity never meets the inside heat inside your wall. Exteriors: teak or bengkirai to match decks. Species trade-offs are compared honestly in the wood guide, including when not to pay for cedar.

• Full-height tempered glass doors and panorama walls where the view earns it
• Hidden LED scenes: warm task light for cleaning, amber ritual light for guests
• Wall controller with lockable limits for commercial use - staff set 85-95 °C, guests cannot push it further
• Ventilation designed per placement: intake under heater, exhaust behind benches - the anti-mould detail most tropical saunas miss

Commercial duty is a different machine

A hotel sauna runs 12-16 hours a day, every day. That is why we fit Harvia commercial-line heaters with high stone mass, oversize the ventilation, and rate the whole cabin for 16 h/day. Heat-up is 40 minutes to working temperature; between guests the stone mass recovers in single minutes. Pair it with an ice bath and the cabin becomes the hot half of a contrast circuit.