The incorporation of phase change materials (PCMs) in buildings increases their thermal mass and hence improves thermal comfort through internal temperature stabilization. In this paper, the thermal per-formance of an active PCM system was compared with that of a passive system. Two identical test huts, each equipped with a control system were used to investigate the potential of passive and active systems for energy-saving and peak load shifting. One of the huts was equipped with PCM-impregnated wallboards, while the other hut was provided with active air-PCM heat storage units designed and fabricated at the University of Auckland. Both huts were cooled with an air conditioner or heated using both solar and electric heaters. For space cooling, the hut with active PCM consumed 8% more electricity to maintain comfort, although the energy storage capacity of PCM used was 50% less than that used in the active application. Over ten days in winter, the energy consumed in the hut provided with an active storage system was 22% less when both passive and active systems had the same amount of energy storage capacity. The investigation of peak load shifting showed 32% less in electricity cost when an active storage system was used. (c) 2020 Elsevier Ltd. All rights reserved.