In 2026, Europe got a common standard for public saunas, steam rooms and warm-air rooms: EN 18164:2026. If you run a hotel, spa, gym or public sauna, or plan to build one, here is what it covers.

EN 18164:2026, Wellness facilities for public use. Climated rooms. Requirements, sets requirements for the design and construction of saunas and other heated rooms used by the public, and for their equipment. CEN approved it on 26 January 2026. National standards bodies had to publish it as a national standard by August 2026, so it now exists as BS EN 18164, DIN EN 18164, SRPS EN 18164 and other national versions. It does not cover electrical safety.

The standard covers climated rooms, meaning rooms with heated air at 30 °C or more, in public use. Public use means an installation open to everyone or to a defined group of users, not reserved for the owner's family and guests, whether or not there is an entrance fee.

So a sauna for hotel guests, gym members or spa visitors is in public use, even if nobody buys a separate ticket. A sauna in a private garden, used by the family and their friends, is not.

Sauna room: 80–105 °C, relative humidity below 10%, measured 1 m above the top bench. Timber construction with stepped benches and a heater with stones. Water can be poured on the stones by hand or automatically. Timber must cover at least 65% of the walls and ceiling.
Warm-air room: 30–80 °C. Any material or combination; the maximum humidity depends on the temperature and follows a curve given in the standard.
Steam room: 40–49 °C at saturated humidity, with closed, moisture-proof surfaces. National rules may set the maximum temperature.
Soft steam room: 30–70 °C, relative humidity below 100%, with a humidity and/or temperature controller.

The 65% timber rule matters for modern sauna design. A sauna with large panoramic glazing or a mostly stone interior may not count as a sauna room under the standard, even if it reaches the right temperature. Check the timber share at the concept stage, not after the module is built.

Construction: floors, including slip resistance and finishes in wet areas; walls, with separate provisions for each room type, including prefabricated steam rooms; ceilings; doors and windows; interior fittings.
Ventilation, defined through the rate at which air from outside the room is supplied.
Heating and temperature control, separately for timber saunas and warm-air rooms and for steam rooms.
Humidification, room drying and fragrance systems.
Light and lighting.
Safety: a safety system for switching heaters on and off, and an emergency call system.

It refers to two other standards: EN 16165 for the slip resistance of floors, and EN 60335-2-53 for the safety of sauna heaters. Electrical installation is outside its scope, so it does not replace an electrical safety check.

A European standard is voluntary in itself. It becomes binding when a national law, a building permit, an insurer or a contract refers to it. EN 18164 is also not a CE marking scheme. It does give everyone one reference: authorities, insurers, operators and suppliers can now point to the same document when they discuss whether a public sauna is safe and well designed. Check with your local authority and insurer what applies to your project.

The commercial grade of the Æqua Core, Cella, Forum and Atrium saunas is built to comply with EN 18164:2026. The interior is thermo-ash timber, floor tiles are R13 slip-resistant, and ventilation is mechanical and controlled by a CO2 sensor: in our CFD-validated design, the air is renewed 6.3 times per hour and CO2 stays below 820 ppm. The residential grade is meant for private use, which the standard does not cover. The mobile Rota RV sauna is not covered by EN 18164.

1. Decide which type of room you are building: sauna room, warm-air room, steam room or soft steam room.
2. For a sauna room, check the timber share of walls and ceiling against the 65% minimum, especially with large windows.
3. Specify slip-resistant floors in wet areas.
4. Plan ventilation and heater controls for the room type, not just heater power.
5. Plan the heater safety system and an emergency call system.
6. Have the electrical installation checked separately.
7. Buy the full text of the national version before you write a specification.

The full standard is sold by national standards bodies, for example BSI (BS EN 18164:2026), DIN Media (DIN EN 18164:2026-04) and ISS in Serbia (SRPS EN 18164:2026). See the commercial-grade saunas on the Æqua page.