RENEWnow - New impulses for the highly efficient energetic renovation of multi-storey buildings and districts

Exploration of an innovative approach for the highly efficient renovation of apartment buildings in Austria. The aim is to develop a new service model (one-stop shop) for property managers and owner associations through a targeted, novel mix of technical and non-technical measures.

Short Description



Motivation and research question

As part of recent research projects, the number of multi-story residential buildings, built between 1960 and 1980 and the unrenovated apartments they contained, was estimated. The buildings from this time have the greatest potential for thermal renovation, as they have a very high heating energy demand and at the same time there are large numbers of such buildings. In contrast to older buildings, in most cases there is no monument protection that would make renovation even more difficult. The main results of this assessment showed that around 42.000 multi-storey residential buildings with around 620.000 apartments are still largely unrefurbished and are therefore available for comprehensive thermal refurbishment. Around 40% of this is in buildings with rental apartments. Since the renovation rate in Austria has been well below 1% in recent years, these figures from 2014 have not changed fundamentally. The question is how the renovation rate, but also the quality of the renovation, can be sustainably increased.

Initial situation/status quo

Although there are already technical solutions for the renovation of multi-story residential buildings (related to window replacement, thermal insulation with composite systems) and for boiler replacement in central energy supplied concepts, the renovation rate has stagnated at a low level for years. This means that the ambitious climate protection goals in the building sector cannot be achieved.

The reasons for the low renovation activities are manifold. With the currently usual renovation processes, techniques and costs and the still relatively low prices for fossil fuels and electricity, the reserves from the monthly operating cost account for property management are not sufficient for comprehensive renovations, and lead to significant increases in rental costs. What is disadvantageous and wrong from an economic as well as an economic point of view is that all costs are not accounted for over the life cycle of the building.

Project contents and objectives

The overarching goal of the proposed exploratory project was to develop the basics that are necessary to increase the current annual renovation rate by a factor of 3 to 5. Based on this, targeted next steps would then be taken towards a broad market launch. The goal is to develop a new service (one-stop shop) for property management and owner associations through a targeted, innovative combination of technical (modular and scalable building technology systems, multifunctional building components, modular construction and standardization, industrial prefabrication) and non-technical measures and to explore all this with leading actors from the industry. The model comprehensively and responsibly addresses the issues of overall organisation, drafting of contracts, planning, financing, implementation, operational management, billing, responsibility for comfort as well as the risk in relation to the quality of implementation and the savings achieved. The integration of renewable energy sources, so-called "tenant electricity models" at building or district level, as well as the interaction with higher-level energy networks, make decisive contributions on the way to an energy-plus district.

Methodical procedure

In the project, the entire process of highly efficient renovation solutions was analyzed with technical as well as non-technical aspects and barriers. Experts from the industry as well as actors and stakeholders from outside the industry were specifically involved. Based on this, new services were explored based on the "one-stop shop" principle, which overcomes the organizational, legal, technical and economic barriers of the current renovation standard, as well as ensuring user comfort and taking account the requirement of sustainability. An important step was the definition and exploration of an easy-to-use portfolio of possible technical renovation modules, assigned to basic building types or the type of energy supply. Representative reference examples, KPIs and methods for assessing the resilience and suitability of possible service models or their successful components were analyzed. From this, recommendations and a methodology for the course of a renovation process are derived.

Results and conclusions

In this exploratory project, a new approach for the highly efficient renovation of apartment buildings in Austria was defined and analyzed together with many stakeholders. This holistic approach and methodology supports property developers and their technical managers in deciding on tailored renovation processes and technical solutions. The result is a methodology for the procedure and the sequence of renovation processes in the form of a "pre-design tool" RENEWnow.


The methodology, analyzes and tools from the project have the potential to be further developed in other projects. The activities from the project continue to mobilize the renovation market, especially the resulting research projects PhaseOut and SüdSan, as well as the innovation laboratory RENOWAVE.AT, all of which help to increase the renovation rate. RENEWnow has initiated a wide variety of developments such as concrete demonstration projects with associated technical innovations, but also a new methodology in renovation planning. It is now clear how refurbishment models such as Energiesprong are to be dealt with, that contracting models will be further developed and further federal initiatives will be necessary.

Project Partners

Project management

AEE INTEC (AEE - Institute for Sustainable Technologies)

Project or cooperation partners

  • University of Innsbruck
  • Nussmüller Architects ZT
  • TBH Ingenieur GmbH
  • Stroomversnelling
  • Energieinstitut Vorarlberg

Contact Address

AEE INTEC (AEE - Institute for Sustainable Technologies)
DI Armin Knotzer
Feldgasse 19
A-8200 Gleisdorf
Tel.: +43 (3112) 5886-369