In the sciences, energy is an important idea to get insight into phenomena, as energy can help to reveal hidden systems and processes. However, students commonly struggle to use energy ideas to interpret and explain phenomena. To support students in using energy ideas to interpret and explain phenomena, a range of different graphical representations are commonly used. However, there is little empirical research regarding whether and how these representations actually support students' ability to use energy ideas. Building on common ways of representing energy transfer, we address this issue by exploring whether, and if so how, a specific representation called the energy transfer model (ETM) supports middle school students' interpretation of phenomena using the idea of energy transfer. We conducted an interview study with N = 30 8th grade students in a quasi-experimental setting and used qualitative content analysis to investigate student answers. We found evidence that students who construct an ETM when making sense of phenomena consider the role of energy transfers between systems more comprehensively, i.e., they reason about hidden processes and systems to a larger extent than students who do not construct an ETM.