Resource efficiency in production and technological innovations are inadequate for considerably reducing the current use of natural resources. Both social innovations and a complementary and equally valued strategy of sustainable consumption are required: goods must be used longer, and services that support collaborative consumption (CC) patterns must be extended. "Using rather than owning" strategies, such as product sharing, have the potential to conserve resources. Based on the results of different German studies, this article highlights the resource-saving potentials of CC patterns and recommendations proposed for policies and further research questions. The purpose of this paper is to show that a general resource-saving potential can be realized by "use rather than own" schemes, depending on the application field and the framework for implementation. CC is suitable for making a positive contribution to achieving the Factor 10 target by playing an important role in changing consumer patterns.

A key challenge of the 21st century is to transform society into one that features sustainable patterns of production and consumption. To achieve this, transition processes need to be designed in key areas such as housing, mobility and nutrition. The design and large-scale implementation of sustainable product service systems (PSS) is regarded a promising approach for sustainability transitions. Real-life socio-technical experiments are an important infrastructure for designing PSS in collaboration with stakeholders and users. In this paper, we argue that transdisciplinary and action research methods are required for institutionalising an experimental setup and developing PSS within such infrastructures. We present the Sustainable LivingLabs (SLL) research infrastructure and its methodology as an example of such experimental settings. It was collaboratively developed with key stakeholders in three consecutive research projects and applied to e.g. heating and space heating. We show new qualities of SLL in relation to existing LivingLabs and approaches for PSS design and present its methodological three-phase model (insight research, prototyping, field testing) of research. Our article contributes to knowledge on a methodological framework and tool-kit for PSS development in SLL with a clear focus on socio-ecological sustainability. Intermediate findings confirm the high influence of user practices on heating energy consumption and show starting points for PSS development: e.g. transformational products, home-automation combined with consulting along value chains. We hypothesise that developing PSS in userand stakeholder-integrated settings supports acceptance and diffusion and, by taking into account users' social practices of utilising novelties, reduces rebound effects caused by incorrect application.

Various experimental approaches of transformative research in real-world settings have emerged. Yet, similarities, differences, and specific contributions remain unclear. A characteristic-based comparison reveals complementarities and provides orientation.Real-world laboratories (RwLs, German Reallabore) belong to a family of increasingly popular experimental and transdisciplinary research approaches at the science-society interface. As these approaches in general, and RwLs in particular, often lack clear definitions of key characteristics and their operationalization, we make two contributions in this article. First, we identify five core characteristics of RwLs: contribution to transformation, experimental methods, transdisciplinary research mode, scalability and transferability of results, as well as scientific and societal learning and reflexivity. Second, we compare RwLs to similar research approaches according to the five characteristics. In this way, we provide an orientation on experimental and transdisciplinary research for societal transformations, and reveal the contributions of this type of research in supporting societal change. Our findings enable learning across the different approaches and highlight their complementarities, with a particular focus on RwLs.

A key factor to energy-efficiency of heating in buildings is the behavior of households, in particular how they ventilate rooms. Energy demand can be reduced by behavioral change; devices can support this by giving feedback to consumers on their behavior. One such feedback device, called the 'CO 2 meter', shows indoor air-quality in the colors of a traffic light to motivate so called 'shock ventilation', which is energy-efficient ventilation behavior. The following effects of the 'CO 2 meter' are analyzed: (1) the effect of the device on ventilation behavior within households, (2) the diffusion of 'CO 2 meter' to other households, and (3) the diffusion of changed behavior to households that do not adopt a 'CO 2 meter'. An agent-based model of these processes for the city of Bottrop (Germany) was developed using a variety of data sources. The model shows that the 'CO 2 meter' would increase adoption of energy-efficient ventilation by c. 12% and reduce heating demand by c. 1% within 15 years. Technology diffusion was found to explain at least c. 54% of the estimated energy savings; behavior diffusion explains up to 46%. These findings indicate that the 'CO 2 meter' is an interesting low-cost solution to increase the energy-efficiency in residential heating.

Purpose -The Hot Spot Analysis developed by the Wuppertal Institute is a screening tool focussing on the demand of reliable sustainability-oriented decision-making processes in complex value chains identifying high priority areas ("hot spots") for effective measures in companies. This paper aims to focus on this tool. Design/methodology/approach -The Hot Spot Analysis is a qualitative method following a cradle-to-cradle approach. With the examples of coffee and cream cheese hot spots of sustainability indicators throughout the entire life cycle are identified and evaluated with data from literature reviews and expert consultations or stakeholder statements. This paper focuses on the indicator resource efficiency as an example of how the methodology works. Findings -The identified hot spots for coffee are the raw material procurement phase in terms of abiotic material, water and energy consumption, the production phase concerning biotic material and the energy consumption in the use phase. For cream cheese relevant hot spots appear in the raw material procurement phase in terms of biotic materials and water as well as biotic materials and energy consumption during the production phase. Research limitations/implications -Life cycle analyses connected to indicators like resource efficiency need to be applied as consequent steps of a Hot Spot Analysis if a deeper level of analysis is eventually aimed at which is more cost and time intensive in the short term. The Hot Spot Analysis can be combined with other sustainability management instruments. Practical implications -Research and management can be directed to hot spots of sustainability potential quickly which pays off in the long term. Originality/value -The paper shows that companies can address sustainability potentials relatively cost moderately.