This article introduces a novel framework for Occupant-Centric Key Performance Indicators (OC KPIs) which aims to increase the understanding of building performance by aligning with occupant presence during the operation phase. Unlike traditional Key Performance Indicators (KPIs), OC KPIs can better emphasize the usefulness of energy use in the building to provide service and indoor comfort to occupants when they are actually present. Within this framework, the study explores 52 traditional KPIs and OC KPIs focusing on heating use, electricity use, domestic hot and cold water, thermal comfort, and air quality. The study case is a multi-story residential low-energy building located in Denmark (five apartments, 16 rooms). The findings suggest that incorporating occupancy data in the OC KPI calculations enables a deeper understanding of energy-related occupant behavior and Indoor Environmental Quality (IEQ). These include 1) the potential for installing a more advanced heating control algorithm by analyzing occupancy over time in relation to heating use, and 2) the identification of significant appliance-related behavior in correspondence with load matching, which can be used for predictive maintenance (e.g., degradation) or personalized energy use feedback. Furthermore, OC KPIs shows the potential to help detect energy use inefficiencies due to system anomalies/faults and/or occupant behavior, and insufficient IEQ indicate and guide towards savings opportunities. In addition to the developed framework, the article discusses the implications of the comparison between the traditional and OC KPIs and the practical implementation of OC KPIs, supporting a paradigm shift towards a more occupant-centric assessment of building performance.