Driven by Europe’s ageing building stock and the EU’s sustainability targets, renovation of existing buildings has become increasingly important. Building renovation typically comprises three types of activities (operations & facility management, condition assessment & monitoring, and transformation planning), each involving key decisions that can benefit from advanced decision support systems such as digital twins (DTs). DTs carry the promise of improved decision-making about, as well as the monitoring and understanding of, the twinned entity. This paper investigates how DTs can support, and add value to, the decision-making involved in building renovation and how the added value of these DTs can be assessed and (ideally be) quantified. In doing so, this paper focuses primarily on operations & facility management-related activities. By connecting use cases with quantification methods, this paper suggests pathways to evaluate and prioritise DT investments in the context of building renovation.