4. Buildings & energy

4.5 Österreichisches Siedlungswerk (ÖSW), Neilreichgasse 9 and Karmarschgasse 20

Partner: ÖSW

The limited-profit housing developer Österreichisches Siedlungswerk (ÖSW) operates several properties in the WieNeu+ programme area. The comprehensive future-proof and climate-resilient refurbishment of these properties is at the centre of the company’s efforts. The findings and results obtained are of benefit to many other limited- and non-profit housing developers and also advance the overall goal of affordable housing.

ÖSW property Neilreichgasse 9

Modern multi-apartment building at a street corner, with a white façade and brown window frames, with adjoining residential buildings in the background

Fig. 20: ÖSW property Neilreichgasse 9. Copyright: City of Vienna / Stephan Hartmann

With regard to the property Neilreichgasse 9, it was planned to carry out a comprehensive refurbishment of the roof, windows, terraces and basement ceiling. The sustainable development of this residential property also contributes to improving the overall housing quality as well as the level of social interactions among residents.

Inter alia, the following interventions were examined:

Setting-up of a 24-kWp PV plant with construction of a battery storage room with storage medium (battery)
Installation of an energy-efficient LED illumination system for the common portions of the building
Connection to the district heating network

ÖSW property Karmarschgasse 20

Modern multi-apartment building with a white façade and brown window frames in Karmarschgasse 20; the property was developed by ÖSW.

Fig. 21: Multi-apartment building of ÖSW in Karmarschgasse 20. Copyright: City of Vienna / Linda Schneider

The street-facing façade of the building in Karmarschgasse 20 was already refurbished in 2019. This was followed by the refurbishment of the courtyard-facing façade, including the loggias and mansard windows, starting in 2021. By the same token, it was planned to set up a 43-kWp PV plant plus the required storage facilities as well as to switch to energy-efficient LED illumination in the publicly accessible portions of the building.

Through the thermal refurbishment of the ÖSW properties Neilreichgasse 9 and Karmarschgasse 20, it was possible to reduce the annual heat demand by approx. 62,900 kWh total. The carbon footprint of the properties was improved by 10.1 tonnes per year.

Outcomes

Due to statutory requirements, limited-profit housing associations find it more difficult to finance ambitious refurbishment projects. In particular, multi-property energy solutions pose a challenge because the principle of self-financing for maintenance and refurbishment ventures is solely focused on single buildings or single housing estates. Price increases of 10% to 12% relating to refurbishment costs put a massive damper on the implementation of such projects. Protracted approval procedures and frequently changing framework conditions for e.g. photovoltaic plants can prevent optimum solutions. Heating system control by AI offers potentials for process-related savings.