Motivation and Initial Situation

Historic urban districts today face a profound conflict of objectives: On the one hand, the building stock is to be converted to a climate-neutral heat supply in line with climate goals; on the other hand, typical general renovations in listed buildings involve high investment and procedural costs. Vienna's Cottage Quarter, with its heterogeneous ownership structures and individually developed building stock, is a prime example of this. The lack of expansion plans for Vienna's district heating network in the district makes it difficult to switch to sustainable heat sources. Pure behavioural changes without technological measures often achieve only limited effects. Against this backdrop, the "Eco-Transformation" project aims to develop an interdisciplinary approach that combines technical innovation, social behaviour, and lean process design into a transferable transformation path. The primary focus is on activating sufficiency and space potentials and creating a neighbourhood-specific methodology suitable for serial implementation.

Project Content and Objectives

The project is divided into work packages that seamlessly intertwine. First, a detailed building analysis was conducted along two axes: first, the assessment of sufficiency potential using simulations of various renovation variants and system temperatures; and second, the determination of space potential in the heterogeneous building stock of Haizingergasse 26, 28, and 30. In parallel, a psychological study using guided interviews and a structured literature review provided insights into the triggers, barriers, and motivations of residents in the neighbourhood regarding renovation projects. One work package was dedicated to the potential analysis at the neighbourhood level, in  which lean principles were applied to serial renovation: standardization of service modules, scheduling of processes, and frontloading in cooperative planning formats. In the next step, a  livephase transformation process and a modular renovation framework ("SMLXL"-system) were derived, ranging from minimally invasive individual measures to comprehensive heat pump and building envelope renovation. It was essential to structure all measures along a decision tree so that they could be combined depending on the initial structural situation and budget.

Results and Conclusions

The thermal simulations showed that moderate renovation steps enable sufficiently efficient heat supply with a maximum flow temperature of 55 °C using heat pumps in all three demo houses. The feasibility studies of the three buildings also highlighted that underfloor heating systems  increase thermal comfort and boost free-cooling-potential but involve higher investment costs. It was also shown that an anergy network cannot exploit its advantages due to the largely homogeneous demand profiles, as there is no simultaneity between heat supply and withdrawal during operation. The area potential analysis emphasized the importance of sufficiency-oriented adaptations of use, which, however, cannot always be consistently implemented in practice. In structural renovations, a lack of information transfer and uncertainties regarding the total costs  represent the main obstacles to further renovation steps.

The psychological assessment based on the step-by-step model of self-regulated behaviour change (SSBC) identified information, self-efficacy, and social norms as key factors influencing willingness to renovate. Building on this, the "Renovation Path" was developed as a communication and management tool that organizes neighbourhoods into "renovation neighbourhoods" and facilitates the exchange of experiences, costs, and processes. At the same time, the Lean analysis provided a process framework suitable for series production: A Kanban-supported JIT logistics system with micro-warehouses, a Last Planner®-based takt board and Gemba walks create a high level of plannability and efficiency. The model application at the Haizingergasse 30 project showed that consistent frontloading workshops and modular scheduling can reduce construction time and costs, while resident involvement significantly increased their acceptance.

Outlook

The findings will form the basis for initial demonstration projects, ideally in at least five to ten comparable buildings to validate the transferability of the process to a neighbourhood scale. Accompanying monitoring of energy consumption, comfort parameters, and user acceptance will provide long-term insights into potential optimizations of control strategies and the further development of geothermal or passive cooling systems. At the same time, digital renovation navigators and training modules for planners, tradespeople, and residents will be established so that the lean or serial approach can be scaled in the construction industry.

Project management

indigo development holding gmbh

Project or cooperation partners

• LeanWorks GmbH
• Ehmayer-Rosinak Cornelia Friederike Dr.
• Schöberl & Pöll GmbH
• sima consulting GmbH

DI Peter Nageler
Lederergasse 22/16
A-1080 Vienna
Tel.: +43 (1) 93 46 315
E-mail: nageler@teamindigo.eu
Web: www.teamindigo.eu