Trends in the cost-benefit analysis of energy efficiency measures as part of the renovation wave

The goal of sustainable development within planetary boundaries poses new challenges to the actors of the real estate industry. One task is to improve the energy performance of existing buildings by deep energy retrofit measures. The aim is not only to conserve resources and reduce emissions, but also to ensure that buildings can be rented out and marketed, and that a loss of value is avoided. In addition to technical issues and aspects of dealing with existing building fabric, questions of assessing their economic viability play a role in the selection of suitable measures. Against the background of a project in Germany to develop a methodological convention, this paper introduces basics for cost-benefit analyses of energy efficiency measures. Furthermore, the following questions will be discussed: (1) How can the introduction of carbon pricing conventions be aligned with external climate and environmental costs? (2) How can be dealt with non-monetary factors in investment appraisals? (3) How can typical perspectives of actors be classified and what are the consequences for the necessary adjustment of appraisal methods? (4) How can the general trend towards greater consideration of uncertainties be taken into account? Possible solutions are discussed and recommendations for action are presented.