Heat Pump Solutions for Existing Buildings Highlighted in German Projects

A regional energy forum in Isny organised a “heat‑pump walk” that demonstrated a 1961‑built, uninsulated single‑family house being reliably heated and supplied with hot water by an air‑to‑water heat pump, resulting in markedly lower heating costs compared with the previous gas boiler.

The Fraunhofer Institute for Solar Energy Systems (ISE) led the research project “LC R290”, involving a consortium of twenty heating‑industry firms, to develop propane (R290) heat‑pump concepts for retrofitting existing multi‑family buildings across Germany. The study showed that no single solution fits all cases; system design must match each building’s size, layout, heating load, space constraints, noise and safety requirements. Both central and decentralized installations that require minimal renovation were evaluated as viable pathways for decarbonising the heating sector.