Double skin facades (DSFs) are often applied as energy reducing elements in modern buildings, but do experience overheating problems in warm seasons which may contribute to increase in cooling loads. There are currently various thermal management devices being used in DSF but have limitations such as secondary thermal transmittance and low energy storage capacity. In this paper, a novel laminated composite phase change material (PCM) blind system with high thermal energy storage capacity has been developed and evaluated in a typical DSF building. The results showed that the integrated PCM blind system was able to keep the average air temperature in the DSF below 35 °C during the monitored period in summer and showed no significant increase as compared with the ambient temperature. The surface temperature of the inner skin of the DSF was also reduced up to about 2.9 °C as compared with the external skin surface temperature thus reducing heat transfer into the building. By using validated numerical models, the PCM blind was found to perform thermally better than a conventional aluminium blind. Finally, design and operational parameters of the PCM blind including the blind tilt angle and its position were optimised. Further comparative studies against other integrated DSF systems are however being encouraged to establish the full effectiveness of the developed PCM blind system.