Energy efficiency is identified as a vital area for addressing sustainability challenges of our time. Governments throughout the world invest vast amounts of resources in research, for advancing knowledge on energy efficiency, and for fostering innovations that can support a transition towards a more sustainable energy system. Evaluation can be an important component in transition processes, for setting directions, assessing outcomes, and enhancing learning. In Sweden, evaluations are undertaken to assess the contribution of energy research to national goals and are also regularly undertaken for individual research programmes and institutions to assess processes and effects. Thus, in a context where evaluations are conducted at different levels and with different objectives, the connectivity between them becomes complex and often unclear. This study focuses on how research is evaluated and how individual evaluations frame and relate the evaluand to an energy transition. By reviewing 20 Swedish evaluations of research for energy efficiency in buildings, we seek to provide insights on the operationalization, analysis, and assessment of the evaluations. The results reveal that evaluations often deploy a systems perspective that frames the initiatives in a larger societal perspective, crucial for supporting a transition. They also highlight a heterogeneity within the undertaking of the evaluation: from a generally wide operationalization--to a more narrow analysis focusing on programme level outcomes--to a wider assessment of impacts and relevance for society and different actors. In all, the full potential of individual research evaluations is still to be harnessed through deliberate evaluation approaches.