The reduction of building energy consumption is a direct target for the many governments worldwide. To date active thermal energy storage (TES) technologies have demonstrated the capability of reducing 30-40% of end-use energy demand. However traditional active TES solutions are integral to the building fabric, making retrofit due to building demand changes difficult to incorporate. Phase change material (PCM) has demonstrated comparable TES ability with five to fifty times less mass, depending on material properties and conditions. PCM solutions therefore offer lightweight TES solutions suitable for retrofit in the built environment. Traditionally PCM solutions have been fitted passively in construction layers, such as ceiling tiles or wall sections. These have suffered from poor heat transfer, leading to poor thermal cycling and performance. Novel Active-PCM solutions have been developed for AC systems saving 34%. Through building simulation this paper investigates a novel method for improving PCM integrated ceiling tile performance. The method proposes using ventilation strategies to improve heat transfer and optimise the benefits of PCM ceiling tile retrofit. The modelled building was constructed and simulated in Design Builder using NCM templates. Ventilation strategies employed were zero ventilation, day ventilation, evening ventilation, night ventilation and twenty-four hour ventilation. The annual energy consumption for heating and cooling was analysed, as well as the total building energy savings. The results demonstrate that coupled night ventilation provided the greatest energy savings in low air-leakage buildings. Further investigation was given to enhancing heating energy savings for mechanically ventilated buildings. Simulation of combined heat recovery and PCM ceiling tile retrofit offered a 72% reduction in annual heating and cooling energy consumption in the reference building.