This research develops a BIM-based multiobjective optimization method (BIMOM) to enhance classroom acoustics, with a focus on reverberation time (RT). BIMOM integrates BIM data, visual scripting (Grasshopper), and the nondominated sorting genetic algorithm (NSGA-III) to optimize acoustic retrofitting based on two goals: achieving target RT levels and minimizing material cost. Design parameters are extracted from the BIM model and fed into NSGA-III, which evaluates design alternatives stored in an optimization library. Optimal solutions meeting RT60 and cost objectives are visualized in the BIM environment. A prototype system is validated using a classroom case study across three scenarios. Results show that BIMOM reduced RT from 6.04s to 0.3–0.8s, with cost ranging from USD 19/m2 to USD 22/m2 (USD 1.77/ft.2 to USD 2.04/ft.2). The system supports cost-effective, data-driven acoustic design decisions.
