Does EN 18164:2026 Apply to Outdoor Saunas?

Key Takeaways

• EN 18164:2026 covers climated rooms for public use. Location isn't in the scope line, so an outdoor cabin falls in or out depending on who uses it.

• CEN approved the text on 26 January 2026, and national standards bodies must adopt it by August 2026.

• A private garden sauna sits outside the standard. A sauna shared by an apartment block is treated as public.

• At least 65 per cent of a sauna room's walls and ceilings must be clad in wood. That's the clause a full-height glass cabin has to answer to.

• The room must reach its specified conditions within 60 minutes and get at least five air changes per hour, or a CO2-regulated control.

• EN 18164 is not a CE mark and it isn't law. It's the document a spa tender and an insurer will quote at you.

• Heater safety stays outside this standard. That belongs to EN 60335-2-53.

EN 18164:2026 never says the word "outdoor", and that silence is what will lose someone a spa tender this autumn. We build cube and barrel saunas in a 2,000 m² workshop in Klaipėda, so the question reaches our desk every time a hotel asks what our cabin complies with. By the end of this article you'll know which rooms the standard catches, where a glass wall runs into it, and the six questions to put to any manufacturer.

Does EN 18164:2026 apply to outdoor saunas?

EN 18164:2026 applies to an outdoor sauna whenever the room is used publicly, and not at all when it's a private garden cabin. The scope turns on use, not on walls. The published text specifies "requirements for the design and construction of climated rooms and any associated equipment for public use" (BS EN 18164:2026, published 2 March 2026, accessed July 2026). Nothing in that sentence mentions a building. So a barrel behind a family house sits outside it, and the same barrel at a campsite, a hotel or a housing co-op sits inside it.

That single distinction decides which of your orders now carry paperwork.

What does EN 18164:2026 actually require?

The full title is Wellness facilities for public use — Climated rooms — Requirements, and it covers four room types: sauna rooms, warm-air rooms, steam rooms and soft steam rooms. Section 4.1 defines a sauna room as one "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" (Lassi A Liikkanen, Saunologia, 2 April 2026, accessed July 2026).

Here's what that turns into on a specification sheet.

The figures above come from the same two published readings of the standard, from Saunologia and from SaunaNews, 18 April 2026 (accessed July 2026).

Does EN 18164 apply to a private garden sauna?

No. A sauna a family builds and uses at home is out of scope, and no national adoption changes that. But the boundary is wider than most dealers assume. Saunologia notes that housing co-ops and saunas shared by several flats inside an apartment building count as public. So do rental cabins, gym annexes and campsite units.

If more than one household uses the cabin, stop treating it as a garden product.

Is EN 18164 the same thing as a CE mark?

No, and confusing the two is the most expensive mistake in this whole subject. SaunaNews puts it flatly: "It is not a CE mark. It is not law. It is voluntary on paper." A CE mark is a different mechanism altogether. The European Commission states that the letters "signify that products sold in the EEA have been assessed to meet high safety, health, and environmental protection requirements", and that "by affixing the CE marking to a product, a manufacturer declares that the product meets all the legal requirements for CE marking" (European Commission, accessed July 2026).

One is a declaration a manufacturer makes. The other is a technical baseline a buyer can demand. A supplier who answers a standards question by pointing at a CE label on the heater has answered a different question.

When must national standards bodies adopt EN 18164?

CEN approved EN 18164 on 26 January 2026, and national standards bodies across the EU and EEA must adopt the text without changes by August 2026, withdrawing conflicting national standards. Much of that has already happened. SaunaNews recorded national editions in Belgium on 25 February, Sweden and Ireland on 26 February, the Netherlands on 12 March, Estonia on 16 March, Iceland on 30 March, Finland on 8 April, Slovenia on 9 April and Austria on 15 April 2026.

So the deadline isn't the risk. The risk is a tender that already cites the standard while your product sheet still doesn't mention it.

What happens when a glass-walled cube meets the 65 per cent wood rule?

This is where we'll speak against our own catalogue. Our cube line puts a full-height panoramic glass wall on one side, clad elsewhere in charred thermowood cut from timber we buy within roughly 200 km of the workshop. In a private garden, the glass area is purely a design decision.

In a public changing block it's arithmetic.

Wall and ceiling surfaces get added up, the glazed area comes off, and the wood share has to clear 65 per cent. A heavily glazed cabin can fail that on paper while being a perfectly good sauna. We'd rather say that in an article than let a partner discover it during a tender review. So, does EN 18164:2026 apply to outdoor saunas? Only where the room is public, and that's exactly where the glass has to be counted rather than admired.

The same honesty applies to heat-up. Liikkanen points out that the 60-minute rule is awkward for high-mass heaters, which store heat slowly and give it back for hours. A manufacturer who assembles and checks each cabin before it ships can put a real heat-up figure on paper. One who ships flat panels for site assembly is guessing, because the finished room never existed in one place.

What should a commercial buyer ask a sauna manufacturer about EN 18164?

Six questions, in this order. Copy them into your next email and send them unedited. A supplier who can answer all six has read the standard, and one who deflects to a heater certificate hasn't. If you want the wider version of this check, we've written separately on how to tell a reliable manufacturer from a reseller.

1. What percentage of the wall and ceiling area in this model is clad in wood, and can you show the calculation?

2. From a cold start at 0 °C outside, how long does this cabin take to reach 80 °C measured 1 m above the top bench?

3. How is ventilation achieved, and does the design give at least five air changes per hour?

4. Are the benches removable, and what's the clearance under the lowest bench?

5. What's the insulation build-up of the wall, in millimetres and materials?

6. Which heater model is specified, and where's its EN 60335-2-53 documentation?

Question two is the one that separates suppliers. Our heaters come from Harvia and HUUM, and their documentation covers the appliance. The heat-up behaviour of the finished room is ours to prove, not theirs.

You don't need to read all 20 pages of the standard this month. Do one thing instead. Print the six questions above, staple them to the front of the next specification sheet a supplier sends you, and don't sign anything until the sheet answers them in writing. A number on a page is a commitment. A verbal reassurance is your problem in August.