RUKU Hired KLAFS’s Export Chief. Now It Faces the US Listing Test.

RUKU Sauna-Manufaktur, a custom sauna builder in Illertissen, Bavaria, has named Thorsten Bichler a managing director, and his brief is growth at home and abroad. The company’s own German legal notice now lists him alongside Philipp Egner as Geschäftsführer of GB Verwaltungs-GmbH, the general partner that runs the Illertissen partnership. Spa Business reports his title as CEO; the legal notice calls the role managing director (Geschäftsführer), a post he shares with Egner. He arrived from KLAFS, where he was director of international sales.

In a post published July 1, Bichler wrote that he had closed “an important chapter” the day before, “after 20 intense and successful years at KLAFS,” and was starting at RUKU that morning with the aim of serving “customers worldwide.” Six days later, on July 7, KLAFS put its retractable S1 on sale in the United States at $44,900 to $51,900. He left KLAFS the week its flagship reached America. Spa Business and its sister title Leisure Opportunities reported the move on July 24, three weeks after it happened.

The former international sales director of KLAFS, which calls itself the market leader, now runs a 30-person Bavarian custom builder whose sales network covers Germany, Austria, Italy and Switzerland, for owners who bought it in January 2025 and want it bigger.

Every sauna heater RUKU sells is, on the company’s own product page, “VDE-tested” and carries “the GS mark.” Those are German marks, and a German mark is not what an American inspector accepts. RUKU discloses no North American listing anywhere in its catalog or on its website. Whether one exists behind the scenes is unverified, because the listing directories are not open to a public search.

He told Spa Business he wants hotel chains

Bichler laid out his priorities to Spa Business, and the long-term one is not a residential plan. “I would like to establish Ruku as a full-service provider for residential and commercial customers in the wellness industry,” he said, so that the company can be “a competent and reliable partner for end users, architects, designers, spa consultants, hotel chains, and other project stakeholders.” Before that, he said, come internal processes, then an expanded product range aimed at existing sales channels and new ones.

Architects, spa consultants and hotel chains make up the commercial specification channel, and it is the harder of the two to enter from abroad, because a hotel project runs through a permit, an inspector, and a general contractor who will not accept an appliance without a listing mark he recognizes. It is also the channel KLAFS reaches in the United States through Design for Leisure, its exclusive dealer for US and Caribbean commercial projects. Bichler is describing the KLAFS commercial model, which he knows well, for a company that has not yet built the residential one outside German-speaking Europe.

Kohler carried KLAFS into the US

Kohler acquired KLAFS in January 2024, and by May 2026 there were KOHLER-branded saunas shipping to American homes with nationwide turnkey installation and a KLAFS FERO heater built for the US. The S1 launch in July carried a Kohler, Wisconsin dateline, and the commercial channel runs through Design for Leisure as exclusive dealer for US and Caribbean projects.

Kohler already had American showrooms, American installers, American plumbing-trade relationships, and the compliance apparatus of a company that has been putting listed appliances into US buildings for a century. KLAFS supplied the product. Kohler supplied everything that gets a product to a jobsite legally.

Bichler worked the sales half of that model. At RUKU, the other half would have to be built too.

The mark on the heater

RUKU’s classic sauna page states that its heaters are VDE-tested and carry the GS mark, and describes them as stainless steel, available free-standing, wall-mounted, or underbench. The infrared side is the same story with a different lab: the heating sections of the Thermium cabins are TÜV-tested and GS-marked. GS, Geprüfte Sicherheit, is a German voluntary safety mark, and both labs are real and rigorous. Neither mark is what an American inspector looks for, which is a listing by a Nationally Recognized Testing Laboratory.

OSHA currently recognizes 21 NRTLs. VDE is not among them. But two TÜV entities are, TÜV Rheinland of North America and TÜV SÜD America, so a manufacturer already working with a German TÜV has a relationship it can extend rather than a vendor it has to find. What it cannot do is carry the German result across. A GS mark is a test against European requirements; an NRTL listing is a test against a US standard, with follow-up factory inspections attached. Same laboratory group, different scheme, and only one of them satisfies an inspector in Texas.

No North American mark appears anywhere in RUKU’s catalog or on its website. The NRTL directories are not open to a public search without an account. RUKU has not answered a written question from SaunaNews about whether any UL or ETL work is underway.

The US standard is also changing. As we reported on April 11, the 2024 International Mechanical Code, Section 914, still requires electric sauna heaters to be listed and labeled to UL 875. ANSI/UL 60335-2-53, the American adoption of the international standard Europe already builds to, published on June 27, 2025. UL 875 did not go away. Adoption of the new standard runs jurisdiction by jurisdiction on a three-year model-code cycle, so a European manufacturer entering the US in 2026 has to pick a lane, pay for the testing, and then discover which of the two standards the local inspector has actually adopted.

The two regimes also do not agree on how hot a sauna may run, which is why European visitors find American cabins cool. RUKU markets a cabin range topping out at 248°F. UL 875 caps the reading at the thermostat sensor at 194°F. Those are different measurements taken at different places and cannot be compared directly, but a manufacturer moving a European cabin into a US listing has to satisfy the American number as the American standard defines it, and that is engineering work before it is sales work.

Getting listed does not require an American parent. What a parent buys is the calendar to absorb a certification program that lands entirely before the first American sale, plus a dealer network waiting on the other side of it. RUKU lists no North American dealer network and has not announced a North American launch.

Three legal notices, three different managements

RUKU publishes its Impressum in at least three places. As of August 1, all three named a different management.

The German page lists Thorsten Bichler and Philipp Egner. The English page, same domain, lists Gotthard Balles and Philipp Egner. The Swiss regional site at bern.ruku-sauna.ch lists Gotthard Balles alone. All three carry the same two register entries, HRA 12697 for the operating partnership and HRB 16261 for GB Verwaltungs-GmbH, so the company is one company. Only the names of the people running it disagree.

Switzerland is more than a translated page: RUKU runs a showroom and sales office in Zurich, and its own English homepage puts Austria and Italy in the network too. What the Swiss imprint shows is who publishes the site, which is the Illertissen company under German law with a German address and phone. Whether a separate Swiss entity exists is a question for the Swiss commercial register, which we have not searched. Either way the export RUKU has actually done is into three neighbouring countries a truck can reach overnight.

RUKU’s sitemap declares an en-us locale specifically, not en-gb. Somebody built that page for Americans. Its newest news item is a regional trade fair in Hochheim in November 2024, its sitemap dates most of those pages to October 2024, and as of August 1 its legal notice still named the previous managing director (it has since been updated to list Bichler and Egner).

The owner sells furniture, metal parts, and auto components

ME Capital Advisory & Consulting is a southern-German family investment firm that buys mid-sized companies from owners with a succession problem. RUKU is the fifth holding on its portfolio page and the only one in wellness. The other four are Plocher Möbelelemente (furniture, 2016), Gutekunst (deep-hole drilling, 2018), G.S. Autoteile (auto parts, 2022), and Heckel Präzisionsteile (precision machining, 2023). One of those, G.S. Autoteile, sells into 21 countries. None of them is a North American channel for a heated wooden room that needs a licensed electrician, a permit, and a listed appliance.

ME Capital publishes headcounts. RUKU is its smallest holding at 30 people, against 85 at Heckel and 65 at Plocher, and the EUR 80 million turnover on that page covers all five companies together rather than any one of them. Thirty people is enough to build custom cabins. It is thin for running a certification program, a US dealer recruitment effort, and a domestic order book at the same time, which is the workload Bichler has described for himself.

KLAFS got a parent that had already solved American distribution. RUKU got a parent that has solved German manufacturing succession four times.

RUKU builds to measure, without mineral wool

RUKU builds to measure rather than to catalog. Cabin interiors run to Nordic spruce and local fir, benches to knot-free, sapwood-free abachi. The insulation, which the company calls Isowood, is wood, air chambers, and aluminum reflective foil with no mineral wool anywhere in the wall, and it carries a 30-year guarantee on consistent insulation quality.

Skipping mineral wool is an unusual choice, and RUKU’s case for it is that fiber insulation in a sauna wall settles and takes on moisture over time while a wood-and-air assembly does not, which is what the 30-year guarantee is written against. RUKU puts a number on it through the trade report: energy savings of around 10 percent and shorter heat-up times against a conventional mineral-wool cabin.

RUKU’s own pages publish no lambda value, no U-value, and no wall thickness, and name no testing body for the comparison. For a home buyer that is a footnote. For an operator heating cabins open to close, seven days a week, it is a line in the energy budget, and the right response to an unbenchmarked 10 percent is to ask which cabin it was measured against, at what setpoint, and by whom.

The heritage is older than the sauna business and the two get conflated. In 1852 Rudolf Kurz founded a sawmill and plaster mill in Illertissen. The family turned it into a wood-processing business, and the sauna operation dates to 1974, which the company states plainly in its own tagline. The current partnership sits in the Memmingen register under HRA 12697.

On August 1 SaunaNews put written questions to RUKU Sauna-Manufaktur and to the KLAFS press office. We asked RUKU for Bichler’s start date and exact title, whether North America is a target market, and whether any UL 875 or ANSI/UL 60335-2-53 certification is underway with an OSHA-recognized laboratory. We asked KLAFS to confirm his role there and his departure date. Neither had responded at publication. This piece will be updated when they do. RUKU has issued no release of its own about the appointment and its company news page has not been updated since 2024. The July 1 start date and the twenty years at KLAFS come from Bichler’s own post; the date the appointment took formal effect in the register is not public.