The Adorf im Vogtland housing association sought to reposition itself as an innovative and modern landlord. Furthermore, the building was in a dilapidated condition, with several apartments vacant. By participating in the research project on sustainable heating of multi-family buildings (LowEx in Existing Buildings), the aim was to implement innovative solutions for heat supply. The housing association received support from federal funding for the future project “Adorf Anders (different).” It is an apartment building with five apartments in a two-family house. It was built in 1963 using prefabricated components from the WBS series. Before the renovation, it was supplied with a central gas heating system without condensing technology, installed in 1993, with a heat consumption of 216 kWh/m² per year. There was no ventilation system. It was renovated in two stages:
1) Conversion to a heat pump system;
2) Building envelope renovation with roof insulation, ETICS with integrated ventilation, and new triple-glazed windows.
Key facts
| Building | Heat Pump and Source | ||
| Location | Adorf, Germany | Number of HP | 1 |
| Construction | 1962, retrofit 2021 | Operation mode | Monoenergetic |
| Heated area | 250 m² | Heat source | Outside air |
| No. of apartments | 5 | Type of system | Hybrid |
| Level of insulation | Very good | ||
| Heating sytem | |||
| Heating temperature | 55/45°C | Heat demand | 35 kWh/(m²a) |
| Installed power | 3-11 kWth | ||
| Other information | |||
| Climatic zone | Cfb | ||
Description of the technical concept
Heat pump system
o 3-11 kW modulating
o Gas condensing boiler 4-28 kW
o Control: Heat pump partially parallel with boiler
o CO2 emission control
o Hot water boiler only
Case study delivered by: Fraunhofer ISE, LowEx Bestand