English

How is it possible to increase homeowners’ insulation activity? Answering this question is key to successful policies regarding energy-efficient buildings worldwide. In Germany, doubling today’s insulation rate of about 1% is an important element for reaching the government’s target of an 80% reduction in energy demand in the building sector by 2050. This thesis uses an agent-based model analysis to improve the understanding of homeowners’ insulation activity and to explore new approaches aiming at its increase in Germany. Two agent-based models were developed and utilized. The first model was developed mainly based on insights derived from a structured literature review. The second emerged from the previous one, incorporating the results of an online survey conducted among 275 homeowners. The results indicate that homeowners’ economic means have little influence on their decision to install insulation. Instead, their insulation decision-making is mostly affected by situational factors and their attitudes towards insulation. Situational factors, such as the condition of the building, are important because they initiate homeowners’ individual decision-making processes on insulation. The simulation results show that improving homeowners’ attitudes about insulation by providing information has a comparatively low potential for increasing their insulation activity. Out of the policy options this thesis explored, the introduction of an obligation to insulate the walls within one year after change of house ownership was found to have the greatest impact on homeowners’ insulation activity. The research has been published in the scope of three peer-reviewed articles: - Friege, Jonas, and Emile J. L. Chappin. “Modelling decisions on energy-efficient renovations: a review.” Renewable and Sustainable Energy Reviews 39 (2014): 196-208. - Friege, Jonas, Georg Holtz, and Emile J. L. Chappin. “Exploring Homeowners’ Insulation Activity.” Journal of Artificial Societies & Social Simulation 19.1 (2016). - Friege, Jonas. “Increasing homeowners’ insulation activity in Germany: An empirically grounded agent-based model analysis.” Energy and Buildings 128 (2016): 756-771.

2 MODELING DECISIONS ON ENERGY-EFFICIENT RENOVATIONS Originally published as: Friege, J. and Chappin, E., 2014. Modelling decisions on energy-efficient renovations: a review. Renewable and Sustainable Energy Reviews, 39, pp.196-208. 3 EXPLORING HOMEOWNERS’ INSULATION ACTIVITY Originally published as: Friege, J., Holtz, G. and Chappin, E.J., 2016. Exploring Homeowners' Insulation Activity. Journal of Artificial Societies & Social Simulation, 19(1). 4 INCREASING HOMEOWNERS’ INSULATION ACTIVITY IN GERMANY Originally published as: Friege, J., 2016. Increasing homeowners’ insulation activity in Germany – An empirically grounded agent-based model analysis. Journal Energy and Buildings, 128, 756–771.