Nowadays, the building sector and people’s activities in buildings account for nearly 60% of the world’s electricity consumption. Wherein, the operation accounts for 87% of total costs in the whole building lifecycle. Hence, it is most efficient in enhancing the sustainable performance in this phase. However, the current information management process in building facilities O&M phase is weak. Towards this problem, a solution of proposing BIM-BMS integration was raised from the literature. Besides, the educational building was identified as the most suitable building type in New Zealand to test. In this regard, the research aims to investigate the effectiveness of BIM-BMS integration in managing existing educational building facilities in New Zealand. Due to the solution belonging to a complex system, this study adopts a complexity theory. Considering this, a conceptual framework of nD BIM-IKBMS was given. In terms of this, a mixed methods approach was adopted for this study in order to meet the objectives of the study. It is comprising of five stages of data collection: a documentation analysis was made to define the BIM related terminologies in a New Zealand context. Then a focus group interview was conducted to obtain New Zealand specific barriers coupled with specific suggestions. Based on the specific suggestions, a functional framework for the solution was developed and verified on its interoperability and flexibility. Under this framework, a process model was established, which was then adopted to develop a working prototype. Once the working prototype was deployed in a pilot case, a thermal model was adapted for simulating the heating costs of the HVAC system in three scenarios. This simulation delivered the evaluation of the effectiveness of our system. The findings of this study revealed that the current New Zealand BIM adoption was still early while the majority of existing BMSs here were not intelligent enough to maintain the energy efficiency. It was further verified that the solution is flexible and capable to be applied on the New Zealand’s situation in relation to educational facilities management. As a result, this study identified that BMS saved 1.52% heating costs in a New Zealand educational building whereas BIM-BMS integration attributed a further 0.68% (totally 2.20%). To emphasize the uniqueness of this study, a New Zealand context was considered to conduct this study. Whereas, a comparison to the results from other researchers all over the world was made to remain the generalization. Considering a wide-ranging variety of projects in different countries, building types, building systems, evaluation method, our findings are limited within the features of the pilot case. Other aspects were recommended in the future study for generalizing, complementing, and optimizing the outcomes of this study.