The heritage building sector is recognised as a promising industry capable of reducing environmental impacts of its buildings. However, their current energy performance still remains low with insufficient research into the causes for their poor performance. Current research on heritage building’s energy performance is mainly concerned with investigating their thermal performance. Meanwhile, statutory conservation requirements for listed buildings remain a challenging constraint on their sustainable energy refurbishment options. There is, however, a gap in terms of specifically investigating their operational energy performance. Exacerbating this problem is the existence of operational islands between the industry’s stakeholders involved in reuse of listed church buildings (LCBs) projects. This study investigated critical factors perceived to be responsible for this problem from the perspectives of the stakeholders’ practices and influence on energy consumption in the reuse of LCBs. A sequential mixed-method research approach was adopted using soft system methodology as the main theoretical perspective. Findings identified four critical factors perceived to significantly influence energy consumption in the reuse of LCBs. These indicate that human ‘subsystem’ factors permeate the individual, institutional and system levels as both a trigger and the most critical factor constituting the biggest challenge to achieving sustainable reuse of LCBs. Results from the study highlight the need for a tool redirecting current practice to improve the operational performance of these buildings. The output from this study is the proposal of a strategic energy management framework which could contribute to the development of a body of theory relating to more sustainable heritage building conservation and asset management. An implication of this study is that a tool, such as this proposed strategic energy management framework could aid designers and facility managers to take informed decisions early in the design and operational practices; supporting them and other stakeholders in achieving environmental sustainability in the reuse of LCB projects. It concludes that if the critical factors are addressed appropriately, environmental impacts of LCBs could be minimised.