Abstract The use of the open energy monitor system was investigated to tackle the performance gap in smart energy systems using an example of a smart energy system as a case study. The system at West Whins is composed of an air source heat pump, a domestic hot water tank, and a solar thermal subsystem which supply space heating and domestic hot water to 6 dwellings. First, a knowledge base of the system at West Whins and the open energy monitor kit was generated. Based on this information and discussions with the end user, 32 key performance indicators were established to monitor system performance, optimise the billing process, and gather data for future control optimisation. Analysis of the initial and additional monitoring capabilities available was carried out. Missing equipment and readings, such as electricity used by the heat pump and outside air temperature, were established. Following this, the input readings were processed using emoncms.org’s data processing capabilities and validated to develop preliminary dashboards that fulfilled as many of the requirements identified as possible. The preliminary dashboards were improved upon the feedback received by the end user to generate the finalised dashboards and Apps. Some of the system performance and anomalies were identified and analysed. Overall, the majority of the key performance indicators identified were included in dashboards, creating a set of dashboards capable of smart energy systems model calibration and ongoing system performance monitoring.