Using and maintaining an outdoor sauna: the complete guide

Short answer: an outdoor sauna requires four fixed habits: drying out with the door ajar after every session, always sitting on the benches with a towel, checking and re-stacking the heater stones annually, and cleaning and, where needed, treating the exterior wood once a year. Never use lacquer or paint inside. Below you will find the specifications per model, the first start-up, a summary of the session and the complete maintenance calendar, with links to the detailed instructions for each topic.

Specifications per model

All models: exterior in thermowood (the Quatro also available in spruce), interior in alder supplemented with thermowood, and a wood-fired or electric heater from Harvia or Huum, matched to the cabin. Custom dimensions, bench layout and options are available per model.

First start-up

1. Check the placement: level, load-bearing, water-draining, door out of the wind, chimney clear. The full step-by-step plan, including the permit check, is in installing an outdoor sauna.
2. Connection: a three-phase supply installed by a qualified electrician for an electric heater; flue gas discharge according to regulations for a wood-fired heater.
3. Stones: rinse new stones and stack them loosely in the heater.
4. First firing: fire the new heater for half an hour to an hour the first time, with no one in the cabin and the door ajar; this burns off production residue on the heater and stones.
5. After that, run the first session as described below.

The sauna session in brief

• Heat to 70 to 90 °C and wait until the stones are fully heated through.
• Shower, dry off, bring a towel, rounds of 8 to 15 minutes, cool down, rest.
• Ladle small scoops of water, never pure oil onto the stones.
• Ventilation: inlet low near the heater and outlet high on the opposite wall, slightly open.
• Afterwards: door ajar, ventilation open, dry out.

The complete session schedule with cooling down and safety is in sauna temperature and loyly; the cold counterpart is in building up cold plunging.

Maintenance calendar

The details are in sauna heater and sauna stones maintenance and maintaining sauna wood.

Glass, door and hinges

• Panoramic window and door glass: clean with a glass cleaner or water with a dash of vinegar and a microfibre cloth; only clean the inside once the cabin has cooled down. No abrasive cleaners.
• Door: should close smoothly. If the door binds, first check whether the cabin is still level; wood settles during the first season.
• Hinges and latch: check every season and lightly lubricate with a heat-resistant product.
• Seals: loose rubber strips or draughts let heat escape and put extra strain on the heater.

Winter

An outdoor sauna is at its best in winter. Bear in mind:

• A somewhat longer heating time in frost and wind; build this into your planning.
• Clear snow from the roof and around the door; keep the roof overhang and chimney clear.
• Dry out extra thoroughly after the session: moisture in a cold cabin is drawn into the wood.
• Electric heater: protect the power supply and outdoor sockets against moisture.

Safety

• Heater and chimney: no flammable material within the prescribed distance; a spark arrestor for wood-fired heaters.
• Never dry towels or clothing on or near the heater.
• Children only under supervision, for shorter periods and on the lower bench.
• If you have heart or vascular conditions, high or low blood pressure, or are pregnant, consult a doctor first.
• If you feel dizzy, go outside immediately, cool down while seated and drink water.