Heat Pump Technology in Timber-Hybrid Construction: Energy-Efficient Heating for Multi-Family Buildings

New residential space has been created through the "Wellandblick" project, situated in a quiet location near the Welland landscape conservation area. The development consists of two identical apartment buildings—each with 12 units—sharing an underground garage and designed with a clear commitment to sustainability. Built using a timber-hybrid construction method and equipped with a 100 kW photovoltaic system, the project also employs future-oriented heating technology. All building systems were supplied by Ziegelbaur Energie- und Gebäudetechnik GmbH, which not only planned the project but also operates it under an energy contracting model.

The goal was to implement a heating solution based entirely on heat pump technology that combines high efficiency with quiet operation and integrates seamlessly into the overall visual appearance. The choice fell on a cascade of three Hoval Belaria pro 24 units, combined with two 1,500-liter EnerVal buffer tanks. Thanks to the combination with surface heating and decentralized domestic hot water preparation, the system operates without the need for electric auxiliary heating.

says Rainer Ziegelbaur, Managing Director of Ziegelbaur Energie- und Gebäudetechnik GmbH and project manager.

Particular attention was paid to noise protection: the Belaria pro impressed with very low noise emissions—a crucial factor, especially in densely built-up residential areas. Its compact design and the visually unobtrusive integration of the outdoor units were also key advantages during implementation. Combined with the on-site PV system, the result is a well-rounded, energy-independent concept.

For the residents, the triple redundancy system ensures operational reliability and comfort. All three heat pumps operate in rotation, covering both heating and hot water needs. The flexible control system ensures balanced load distribution, extends the equipment's service life, and maximizes supply reliability. Should one unit fail, the other two take over without interruption. Residents also benefit in their daily lives: the system operates whisper-quietly, requires little maintenance, and ensures even heat distribution thanks to underfloor heating.

Planning began in September 2023, and project implementation started in April 2024. The first apartments were ready for occupancy as early as November, and full occupancy was achieved by February 2025. The project team rated the collaboration with Hoval consistently positively: "Thanks to precise preliminary planning, clear blueprints, and technical support, commissioning went smoothly. The electrical wiring is clearly laid out, and the units are very easily accessible. For us as the installation company, the well-thought-out design of the units was a real advantage during implementation," said Ziegelbaur.
Another plus: Delivery and coordination by Hoval went seamlessly. The project team was closely involved right from the planning phase—covering everything from hydraulic design to the sizing of buffer tanks and domestic hot water systems.