Members of the University of Maine Physics Education Research Laboratory are studying student understanding of the phenomenon of quantum tunneling through a potential barrier, a standard topic in most introductory quantum physics courses. When a series of interviews revealed that many students believe energy is lost in the tunneling process, a survey was designed to investigate the prevalence of the energy-loss idea. This survey was administered to populations of physics majors at the sophomore and senior levels. Data indicate that interview results are shared by a somewhat larger population of students and give insight into additional models of reasoning (e.g. analogies to macroscopic tunnels) not found in the interviews.