Therme Group
Therme Group RHTG AG is an international developer, owner, and operator of large-scale wellbeing destinations that combine thermal bathing, spa and sauna facilities, wellness, cultural programming and sustainable architecture. Headquartered in Vienna, the company operates some of Europe's largest thermal facilities and is currently expanding into North America, Asia, and the Middle East.
History
Therme Group was founded in 2011 in Austria. In 2017, the Austrian industrial holding A-HEAT Allied Heat Exchange Technology AG, which already held a minority stake in Therme Bucharest, acquired a 51% interest in the company to support international expansion. That same year, Therme Group established several subsidiaries, including Therme ARC GmbH, which carries forward the architectural vision of the late Josef Wund. Wund, who died in 2017, had been a major influence on the design of Therme Erding and Therme Bucharest.The company transitioned to a joint-stock corporation in 2017 and began pursuing growth in new markets. In 2019, Therme entered a research partnership with the University of Glasgow’s COGITO group to study the psychological impact of thermal environments on wellbeing.
By 2020, the majority shareholder of Therme Group RHTG AG had become RHTG Holding GmbH, controlled by Therme founder and CEO Robert Constantin Hanea. A-HEAT retained a 19% minority interest with ongoing financial commitments.
In 2023, Therme partnered with the University of Surrey and the UK government to co-develop digital tools that measure the carbon footprint of tourism assets, including a blockchain-based "carbon tokenomics" model.
In 2024, Therme acquired Therme Erding, previously operated by the Wund family, consolidating its position as operator of two of Europe’s most visited thermal resorts. The acquisition was backed by €320 million in new financing, received from Macquarie Capital’s Principal Finance team with its own equity.
In February 2025, Therme Group announced two additional investments to support global expansion. It formed a joint venture with the New York-based Georgetown Company, which acquired a 25% stake in its U.S. business. Separately, asset manager Sculptor Real Estate committed up to €245 million to fully fund the development of Therme Manchester. The company reported that these investments support over $1.5 billion in planned development across the United States.
Later in 2025, Therme formed a €1.25 billion joint venture with CVC Capital Partners, named Therme Horizon, focused on European growth and co-developing Therme Manchester.
Investments and ownership structure
Therme Group is majority-owned by RHTG Holding GmbH, led by CEO Robert Hanea. A-HEAT Allied Heat Exchange Technology AG holds a 19% stake.The company has raised funding from institutional partners, including a strategic joint venture with CVC Capital Partners. Its financing model combines real estate investment, infrastructure funding, and long-term operational management.Locations
Therme Bucharest (Romania)
Opened in 2016, Therme Bucharest is one of the largest indoor wellness centers in Europe, with thermal pools, saunas, botanical gardens, and spa facilities. It was the first LEED Platinum-certified wellness facility in the world, and receives over 1.2 million visitors annually.Therme Erding (Germany)
Acquired in 2024, Therme Erding is the world’s largest indoor thermal resort. It includes multiple themed areas, wave pools, and over 30 saunas, attracting more than 2 million visitors each year.Therme Bad Vilbel (Germany)
Located near Frankfurt, Therme Bad Vilbel will feature thermal bathing, wellness zones, restaurants, and green parkland. The design emphasizes sustainability and urban integration.Therme Manchester (United Kingdom)
Planned as one of the UK’s largest wellbeing attractions, Therme Manchester received planning approval in 2020 following public consultation. The £400million facility is backed by Therme Horizon, the CVC joint venture. It has been described by local officials as a “transformative cultural and wellness hub.” The location will be double the size of the Bucharest location, and will include 20 on-site saunas, 25 water slides, 20 restaurants, and colorful botanic gardens set to open in 2028. Sustainable construction is being implemented, including utilizing locally-sourced materials, air source heat pumps, on-site 3D printing of building components, and reducing waste and emissions with accelerated delivery. The destination is projected to create around 2,500 construction jobs, and will employ 650 staff to operate the resort.A Beyond Groundbreaking launch ceremony in September 2025 brought together politicians, partners and community members to celebrate the beginning of the construction work for the first UK city-based wellbeing resort.Therme Canada, Ontario Place (Toronto)
In partnership with the Ontario government, Therme is developing a C$700 million wellness destination at Ontario Place. The project includes thermal baths, indoor and outdoor attractions, and 16 acres of public parkland co-designed with the Mississaugas of the Credit First Nation and will remain free to access. It has faced public scrutiny and political debate since its announcement in 2021. In April 2025, the New York Times published an investigation into Therme Group’s involvement in the Ontario Place redevelopment and reported that Therme may have inflated its credentials and incorrectly claimed to have the required 100 million CAD equity to meet the province's bid requirements. The report raised questions about the company’s financial qualifications, transparency of the public tender process, and political oversight.Criticism has also focused on the balance between public and private space in the Ontario Place plans. In December 2024, the Auditor General of Ontario criticized the Therme Canada project on the Toronto waterfront as opaque and unfair and that the Therme Group had included information about "Therme" projects that it did not control in its bid. In response, Ontario Premier Doug Ford and Minister of Infrastructure Kinga Surma defended the selection, citing due diligence. A subsequent report from Ontario’s Auditor General confirmed that Therme met the province’s net worth threshold and lease requirements.
Canadian company Groupe Nordik, which has operated spas under the similar "Thermea" brand since 2015, including a location in the Toronto suburb of Whitby, Ontario, insists it has no affiliation with Therme Group, saying that it has filed legal actions challenging Therme Group's use of the "Therme" name in Canada.