Austrian Pilot Project

Creating a building typology for refurbishment of large scale residential buildings for the Viennese building stock

The City of Vienna owns 220,000 flats and is therefore the largest public housing owner in Europe. The public enterprise “Stadt Wien – Wiener Wohnen” is in charge of the maintenance and renovation of the residential buildings owned by the City of Vienna. The administration unit MA 39 (inspection, monitoring and certification authority) is responsible for the calculation of EPCs and technical consultancy for these buildings.

Until now, there was no database available in Austria, where EPC issuers could gather data on possible refurbishment measures from. Some regional agencies have established databases of their own which however are not generally accessible.

In the building performance certificates refurbishment recommendations are sometimes missing or in other cases measures are suggested which do not fit the respective building. The reason for that is that the wall mounting often is not known. To be able to offer high quality measures for the buildings of “Wiener Wohnen”, building typologies were developed together with the MA 39 especially for the buildings of “Wiener Wohnen”. The energy efficiency measures were defined for the different types of buildings. These measures may also be applied to similar other buildings not owned by the City of Vienna. There are a lot of houses built in the so called Wilhelminian style, and tailor made refurbishment measures especially for these buildings have to be developed.

The developed building typology for the multi-family houses was done at first by studying their geometry, their construction type, construction period, building physics and their heating supply system. Then refurbishment measures and generated savings on energy according to the building typology and low energy consumption were defined.

The building typology gives an overview of the existing Viennese building stock and is considered a good base for demonstration of effects of energy efficient refurbishment measures. It also offers a survey of existing EPCs for the building stock and reduces the frequency of errors within the first consultative estimation. Furthermore it predicts the investment and saving/performance indicators. And it is an important instrument to quantify energy and carbon emission reduction potentials. The study is a decision-supporting tool to define energy standards and strategic policy making on municipal level.

The pilot project study was evaluated by different target groups such as building owners, architects, energy experts, etc. They believe that it will have a direct effect on refurbishment actions because of the faster and more efficient process.