This paper presents a study on the integration of two building technologies into one new unified from for application in residential and small commercial and industrial buildings. Structural insulated panel (SIP) technology was utilized as a structural vehicle, and also for thermal insulation, and phase change materials (PCMs) provided distributed thermal mass. This new type of wall panel was termed phase change material structural insulated panel (PCMSIP). The research conducted during this study provided the foundations for the development of this type of thermally enhanced wall panels and evaluated their thermal performance, based on heat transfer rate reduction, under full weather conditions. On average, the peak heat flux reductions produced by the PCMSIPs in combination with 10% and 20% PCM were 37% and 62%, respectively. The average reductions ill daily heat transfer across the PCMSIPs were 33% and 38% for concentrations of 10% and 20% PCM, respectively. The percent PCM concentration was based on the weight of the interior wallboard. (C) 2007 Elsevier Ltd. All rights reserved.