Education buildings, as the third highest consumer of energy in the United States, provides significant opportunities to lower greenhouse gas emissions by increasing energy efficiency (EE). Higher education institutions (HEIs) campuses exhibits multiple favorable but unique attributes, including access to capital, multiple stakeholders involved with differing needs, and control of heterogeneous buildings that are energy intensive, such as laboratories, medical research facilities, sports facilities, and food services. There is a great opportunity to conserve energy by retrofitting these buildings. The decision to retrofit involves many stakeholders and also many factors that are interrelated. This study aims to understand the decision-making processes in EE projects at a higher education institution, particularly the exhaustive list of factors that facilities managers consider when making decision and their interrelationships. Using in-depth semi-structured interviews of facilities managers and secondary data from reports and policy documents, a case study at a large higher education institution is conducted. The content analysis of the data identifies decision factors that are categorized into five major categories: economic feasibility, environmental impact, institutional characteristics, occupant impact, and technical practicality. Interactions among factors are depicted in a causal loop diagram that shows cause-effect relationships. Three main loops highlight the major concerns-economic feasibility, occupant impact, and technical practicality. (C) 2019 Elsevier B.V. All rights reserved.