A novel form-stable phase change wallboard (PCW) was prepared for low-temperature latent heat thermal energy storage by incorporating eutectic mixture of capric acid and stearic acid and gypsum wallboard. Thermal properties of form-stable PCW were measured by DSC analysis. The form-stable PCW has good thermal reliability with respect to the changes in its thermal properties after accelerated thermal cycling. Thermal performance test indicated that the use of such a type of PCW can decrease indoor air temperature fluctuation due to absorption of heat by the eutectic phase change material. Copyright (C) 2007 John Wiley & Sons, Ltd.