The building sector's substantial environmental impact, responsible for 40% of total energy consumption and one-third of CO2 emissions globally, emphasises the urgency to enhance energy efficiency. While there are potentials for energy savings, there are still challenges that need to be faced. In particular, a significant ‘performance gap’ exists between the predicted and actual energy usage in buildings. This gap, observed during the operational phase, poses challenges for realising high-performance buildings. The focus of this thesis will be on renovated office buildings, acknowledging their significance in sustainability efforts. A critical aspect of the performance gap is attributed to the operation and maintenance of the energy systems compared to the intended usage. The research will therefore address the critical main research question: “How can operation and maintenance-related energy performance gap in renovated office buildings be effectively addressed to meet the Paris Proof commitment targets?” By conducting literature reviews and employing a mixed-method approach, including both qualitative and quantitative methods combined, the study will utilise interviews and a case study, using data from advanced systems. Focusing on the complexities of influencing factors, specifically in operation and maintenance, the research aims to address the energy performance gap. Findings indicate that the main challenges are knowledge gaps among stakeholders due to fragmented collaboration, inadequate commissioning and monitoring, and tuning practices, including the lack of a feedback loop. A strategic roadmap of a restructured redevelopment process is proposed, emphasising enhanced commissioning practices, continuous monitoring, and improved stakeholder collaboration. The strategic roadmap therefore suggests practical steps for addressing the performance gap, fostering more energy-efficient building operations, and aiming for redeveloped office buildings to achieve the Paris Proof standards.