The high Air Change Rates (ACRs) required for cleanrooms makes them energy intensive. This research elaborates on three strategies for energy efficient ventilation in pharmaceutical cleanrooms: Fine-tuning, Demand Controlled Filtration (DCF), and optimizing airflow pattern. To study the possibilities for fine-tuning and DCF, two case studies were investigated and simulations were performed to assess the potential of both options. Experiments in a demonstration cleanroom were used to examine how an ideal airflow pattern may be achieved in the cleanroom, resulting in a high contaminant removal efficiency. Results showed that DCF could lead to substantial energy savings, up to 93.6% in the specific case study facilities. Besides this, DCF based on occupancy could be implemented with negligible effect on the environmental cleanliness requirements. Fine-tuning, based on particle concentration, required representative measurement of the concentration in the cleanroom. It was more difficult to implement in practice. With respect to contaminant removal efficiency, best results (within the experiments performed, ACR in the range of 16h-1 - 38h-1), were obtained when air was supplied without a diffuser above the product area and when the work position was located close to the air extraction grilles.