All-in-one propane heat pump for apartments
21st September 2025
GERMANY: A German residential real estate company plans to install over 1,000 packaged air-source propane heat pump units in apartment buildings.
Vonovia SE has entered into a strategic partnership with Austrian start-up company EnerCube GmbH and innovative production company DFA Demonstrationsfabrik Aachen GmbH to advance the series production of EnerCube’s Cube.
The Cube is a compact heating system that combines all key heat pump components within a compact unit. The Cube is installed outside buildings in residential areas to provide heating and hot water to apartment buildings.
The plan is to install 1,000 Cubes in Vonovia properties across Germany by the end of 2029.

The Cube is available in a range of power ratings from 20kW to 80kW to provide heating for up to 40 homes.
All components, including propane air-source heat pumps, heat storage units, hot water heating, circulation pumps, pressure expansion, electrical systems, control technology, and sound insulation is prefabricated in a single outdoor enclosure. The largest unit measures 7.4m × 2.6m × 2.7m.
A pilot project in Donauwörth is reported to have been a “resounding success”, achieving claimed energy savings of 40%.
The Aachen-based company DFA Demonstrationsfabrik Aachen GmbH (DFA), the central manufacturing environment of RWTH Aachen university, will now lead the industrial rollout of this solution. DFA specialises in the fast scale-up of innovative products – from pilot series to full-scale production.
Mass production of the Cube has now begun and 30 systems are expected to be operational by the end of the year.