Europe Finally Has a Sauna Standard. The Nordics Aren't Sold.

Europe just got its first common rulebook for public saunas. EN 18164:2026, approved by CEN on January 26, 2026 and issued as a European Standard the following month, is the first continent-wide technical baseline covering sauna rooms, warm-air rooms, steam rooms, and soft steam rooms in public facilities. National standards bodies across the EU and EEA are obliged to adopt the text without changes by August 2026, at which point any conflicting national standards must be withdrawn.

It is a big deal, and not for the reason most American operators assume. EN 18164 is not a CE mark. It is not law. It is voluntary on paper. But it is also now the reference baseline for every European public sauna tender, retrofit, and insurance conversation, and Finnish experts are already arguing that it freezes a particular Central European idea of sauna rather than the real thing.

What CEN Actually Passed

The publicly available preview of the final text confirms the structure. Scope: design and construction requirements for public climated rooms and associated equipment, with electrotechnical aspects explicitly excluded. Architecture: ten clauses covering classification, construction, ventilation, heating and temperature control, steam and humidification systems, lighting, and bibliography. Normative anchors: EN 16165 for slip resistance and EN 60335-2-53 for sauna heating appliances. Twenty pages total.

National publication has moved fast and unusually uniform for an EN adoption. Germany, Belgium, Ireland, Sweden, Estonia, Iceland, Austria, the Netherlands, Denmark, Finland, and Slovenia have all surfaced national editions or publication notices. No national technical deviations have appeared in the catalogue entries reviewed.

That tight convergence matters. It means a sauna operator in Tallinn, Stockholm, Munich, and Dublin is now working from the same technical vocabulary for the first time, and design consultants exporting work across borders can stop rewriting specs for every jurisdiction. For Bulgaria, Croatia, Cyprus, Czech Republic, France, Greece, Hungary, Italy, Latvia, Lithuania, Luxembourg, Malta, Norway, Poland, Portugal, Romania, Slovakia, and Spain, national transposition records have not yet surfaced in public catalogues as of mid-April, but the CEN adoption obligation applies through the August deadline.

What the Standard Actually Says About a Sauna

EN 18164 defines four public room classes: sauna room, warm-air room, steam room, and soft steam room. These are not marketing labels. They are technical classes with climate envelopes attached, and the most significant one is the sauna-room definition in Section 4.1. The text, as reproduced by Saunologia's Lassi Liikkanen in his April 2026 analysis of the standard, reads:

The sauna room is made of timber with ascending stepped benches and with a room climate of 80°C to 105°C and a relative humidity of < 10 % measured 1 m above the top bench, which is set by a stone-filled heater.

EN 18164:2026, Section 4.1 (reproduced in Saunologia, April 2026)

Translated to US customary: the sauna-room class requires a measured climate of 176°F to 221°F, relative humidity under 10 percent, measurement taken roughly three feet above the top bench, with a stone-filled heater producing the heat and stepped timber benches defining the room. That is an unusually specific definition for a European standard.

Beyond Section 4.1, Liikkanen's analysis (the most detailed public reading of the paid standard in circulation) summarizes these additional requirements from the document:

The soft-steam class allows much lower temperatures at much higher humidity. Liikkanen reports the class permits conditions up to roughly 158°F at 90 percent relative humidity. The steam-room and warm-air classes fall in between. The exact numeric envelopes for those three classes are not as cleanly quotable as Section 4.1 because the paid text is copyrighted and only a short excerpt has been circulated publicly.

The commercial consequence of that taxonomy is straightforward. Every public room in Europe currently marketed as a sauna now has to answer a simple question: does it actually meet the sauna-room class under EN 18164, or is it technically a warm-air room sold under the wrong name? Plenty of lower-temperature public rooms, especially those catering to older or heat-sensitive guests, will not clear the sauna-room bar. The lowest-friction path for those operators is honest reclassification in brochures, booking flows, and on-site signage rather than a retrofit that may not be economically worth it.

Built for Architects, Not Operators

EN 18164 is a construction standard. That is the single most important thing to understand about it. The table of contents has dedicated clauses for wall buildup, ceilings, doors, windows, wet-area finishes, slip resistance, ventilation, room drying, heating and temperature control, steam and humidification technology, and lighting. It does not have a chapter on staff training, infusion procedures, supervision ratios, or house rules. Those still live in trade-association guidance, employer SOPs, and local public-health law.

Electrotechnical aspects are expressly excluded from the scope. For anything involving the heater itself, the standard defers to EN 60335-2-53, which is the international electrical safety baseline for sauna heating appliances. That is the same IEC-rooted standard the United States finally adopted as UL 60335-2-53 in June 2025. The practical effect is that a European public-sauna project now has to manage at least two standards in parallel: EN 18164 for the room, and EN 60335-2-53 for the box that heats it.

Where the Nordic Pushback Actually Lands

The standard has supporters and critics, and the two sides agree on almost nothing. Germany's Deutscher Sauna-Bund framed DIN EN 18164 as a constructive safety benchmark in a late-March news item and published a paid explainer through its own channels. The Finnish Sauna Society flagged the release in its March 31 magazine with a short nutshell summary. The sharpest public critique is Liikkanen's, and it is worth reading closely because it is the first serious technical objection to a pan-European sauna baseline from inside the Finnish tradition.

Liikkanen's four specific critiques, in his own words:

The sauna definition is too narrow. Pointing to epidemiologist Jari Laukkanen's long-running Kuopio cohort data, Liikkanen notes that most Finnish saunas measured in that research operate around 169°F (76°C) on average, below the 176°F (80°C) floor in Section 4.1. His language is blunt: plenty of real Finnish saunas, he writes, "would not meet the standard criteria because they are too cold or don't have enough wood cladding." This is a cultural objection with a research citation behind it, not a stylistic complaint.

The 60-minute heat-up requirement punishes large-stone-mass heaters. Liikkanen writes that the requirement "will be difficult for some heater manufacturers to digest" and that it "invalidates the use of heaters with a notable stone mass." Those are the heaters favored by many traditional Finnish builders for thermal stability and löyly quality. If his reading holds against the full text, this is the single clause most likely to move product roadmaps.

The soft-steam class is too permissive. Liikkanen calls the definition "ambiguous" and "all-encompassing," and notes it can include conditions he describes as "uninhabitable for humans (say, 70°C at 90 % RH)," which works out to roughly 158°F at 90 percent relative humidity. A class that covers both something pleasant and something medically risky is, he argues, not much of a class.

Accessibility is thin. Liikkanen writes that the document contains "hardly any points on 'universal design or accessibility,'" a meaningful gap given the EU's broader equality agenda. He also argues that controlling carbon dioxide matters more than hitting a fixed air-exchange rate: "more important to control CO2 than produce a certain ventilation volume." Both points are explicitly his view, not language in the standard.

Liikkanen is measured about the document overall. He calls it Europe's first comprehensive sauna standard and treats it as a meaningful step rather than a failure. What he does not do is pretend that a Central European definition of sauna captures the living Nordic and Baltic tradition. Neither side in that argument is entirely wrong.

Voluntary on Paper, Mandatory in Practice

Both the European Commission and CEN-CENELEC are explicit that European standards are voluntary unless referenced by legislation. The EVS product page for EN 18164 shows no linked directives or regulations. This is not a CE-marking instrument and does not create a new conformity pathway for public-sauna construction.

Treating it as "optional" is a mistake anyway. Four places will start quoting EN 18164 almost immediately: procurement specifications written by architects and consultants, local building-approval discussions where officials cite recognized technical practice, internal risk management at facility operators, and post-incident liability arguments after slips, door malfunctions, overheating claims, or air-quality complaints. In any of those settings, a facility that cannot demonstrate alignment with the standard has to explain why.

Insurance underwriters have not yet published bulletins specifically on EN 18164, but the standard's coverage of slip resistance, door hardware, heating control, ventilation, and hygiene-adjacent construction details overlaps cleanly with the things loss adjusters ask about after a claim. Expect harder questions on room classification, design records, and maintenance documentation in the next renewal cycle for European public-sauna policies.

What U.S.-Facing Manufacturers Should Watch

For American operators, EN 18164 looks like a European problem. It is more complicated than that for any manufacturer with a meaningful European footprint. Harvia sells across all of it. KLAFS is a German household name under Kohler ownership since 2023. HUUM, SaunaLife, and Auroom are all Estonian brands exporting into the same regulatory block. Harvia's 2025 full-year numbers show how much of the group's volume depends on European commercial projects that will now specify to EN 18164.

The structural pressure on manufacturers is on documentation and positioning, not a new certification fee. There is no new CE label to chase. What changes is that European tenders will increasingly specify room type, heating strategy, ventilation assumptions, humidification technology, and construction context in the standard's language. Brands with clean technical data sheets and a clear story about how their heater, controller, and bench package fits the sauna-room class will win a disproportionate share of specification-driven work. Brands selling on price alone into public projects will find the conversation harder.

There is a U.S. angle worth flagging. European manufacturers newly comfortable with EN 18164 also build to EN 60335-2-53, which is now the same base text as the U.S. UL 60335-2-53 First Edition. For brands contemplating a bigger push into North America, the regulatory translation work just got easier. That matters for the competitive balance as domestic and Canadian brands wrap up their own recertification under the new U.S. sauna heater standard.

For builders, installers, and design consultants working on European jobs, the practical checklist is short. Decide room by room which class each space should declare. Confirm that every space marketed as a sauna can actually hit the required climate envelope. Document ventilation intent, not just ventilation openings. Keep slip-resistance evidence on file against EN 16165. And do not assume EN 18164 covers the heater itself. It does not.