Despite extensive political funding programs, the energy consumption in Germany for space heating and hot water stagnated on a high level of 870 TWh over the past few years and even exceeded the level of 2010. To reduce consumption and meeting the energy-efficiency goals set by the German federal government, an option for private homeowners is to participate in community energy systems (CES). However, homeowners' reluctance to join CES constitutes a major issue. Recent research has not provided deeper insights into reasons for this hesitation. Focusing primarily on local district heating systems, we use two theoretical approaches, motivation and attribution theory, to shed light on drivers and barriers in the decision-making process of homeowners. To gain insights, an explorative research design was chosen, and 22 problem-centered interviews were conducted with homeowners as well as experts.Our results show that subjectively perceived energy autonomy can be a barrier for private homeowners to participate in CES. Furthermore, we find a discrepancy between objective energy autonomy, as defined from a technical perspective, and homeowners' perception. Regarding this, the two major aspects shaping homeowners' perception of energy autonomy are (1) perceived independence from third parties as well as other external influences, and (2) a sense of control over the home energy system and its costs. Our study provides new insights into the decision-making process of homeowners to participate in CES. Additionally, we identified several implications in how far practitioners can address subjectively perceived energy autonomy issues to reduce inertia to join CES.