- Field data confirms efficiency and economic viability: Sunmaxx technology delivers high and reliable overall performance, even under very demanding weather conditions and across varying system configurations. The field data demonstrates excellent results, even during the cold 2025/26 heating season with seasonal performance factors exceeding 4.5. This clearly shows that maximum output and optimal use of surface area can be effectively combined with Sunmaxx.
- Renewed quality label supported by real-world data: As part of the successful recertification of the Solar Keymark label, Sunmaxx is publishing comprehensive data from its operational PVT systems for the first time. In scientific collaboration with the renowned SPF Institut für Solartechnik in Switzerland, the efficiency, system design, and annual performance of the PVT modules were analyzed in detail.
- Proven key technology for the heating transition: With high economic efficiency and verified system reliability, Sunmaxx position themselves as a technology partner for the decarbonization of heat supply and industrial processes.
Sunmaxx, a technology leader in photovoltaic-thermal (PVT) modules, has published extensive field data from a range of installed systems. The focus is on the uncovered and uninsulated Sunmaxx PX-1 PVT collectors, featuring a flat absorber fully bonded to the PV laminate, used as sole heat source for brine-to-water heat pumps. The measurements show that stable source temperatures for the heat pump can be achieved even in winter under monovalent or monoenergetic operation. Under solar irradiation, source temperatures are significantly above ambient temperature; without irradiation, they remain only a few Kelvin below it. The analyzed systems feature PVT array sizing between 2.0 and 4.5 m² per kW of heat pump output (at B0/W35). Even during the cold 2025/26 heating season, seasonal performance factors exceeding 4.5 were achieved in monovalent operation with a system size of just 2.8 m²/kW.
Sunmaxx placed particular emphasis on transparency and real-world relevance. The system data originates from actual projects in operation under real rooftop weather conditions. The publication was carried out in collaboration with the SPF Institut für Solartechnik in Rapperswil, Switzerland, which also conducted the Solar Keymark recertification of the Sunmaxx PVT modules. This Europe-wide recognized label is regarded as a key quality benchmark for solar thermal systems and the leading certification for PVT technologies. The renewal confirms the high performance, reliability, and compliance standard of the hybrid modules manufactured in Saxony.
Dr. Wilhelm Stein, CEO of Sunmaxx, comments: “The renewed Solar Keymark certification underscores our commitment to combining industrial scalability, high performance, and maximum system compatibility in a single technology. A successful heating transition requires solutions that are not only innovative but also reliable under real-world conditions – both in residential and industrial applications.”
With this successful recertification, Sunmaxx strengthens its position as a reliable partner for the decarbonization of buildings, industrial processes, and district heating networks. At the same time, the company establishes a key foundation for funding eligibility, investment security, and the accelerated market ramp-up of PVT systems as a key technology for the heating transition.
Sunmaxx‘ and SPF Institut für Solartechnik’s publication is available in German at sunmaxx-pvt.com/de/loesung/downloads/.
About Sunmaxx
Sunmaxx is a leading manufacturer of PVT modules. Headquartered in Ottendorf-Okrilla near Dresden, the company operates the world’s largest industrial-scale production facility for hybrid modules that combine photovoltaics and solar thermal energy in a single system. Sunmaxx’s innovative technological approach makes PVT a cost-effective alternative to conventional renewable heating systems and enables the full decarbonization of heat supply and industrial processes.
About the Solar Keymark
The Solar Keymark is a Europe-wide recognized quality label for solar thermal systems. It certifies independent product testing and compliance with relevant European standards in terms of performance, safety, and quality.
About t he SPF Institute for Solar Technology
Founded in 1981, the SPF Institute for Solar Technology is part of OST (Eastern Switzerland University of Applied Sciences in Rapperswil, Switzerland) and is one of Europe’s leading research institutions in renewable energy. Around 50 employees operate a broad-based research laboratory as well as an internationally accredited testing facility. The close integration of research, development, and independent testing makes SPF one of the key certification bodies for solar thermal systems and PVT technologies.