Taiwan is limited in space with dense population, and is located in sub-tropical region with high ambient temperature and humidity. In this research, the phenolic resin is proposed as building materials to use its thermal insulation property for developing a comfortable living and working indoor environment. The phenolic resin is an environmental friendly material, and an excellent thermal barrier. The literature also points out that using phenolic resin plates in buildings will decrease or increase the indoor room temperatures by 1°C during summer and winter, respectively, with 10% savings of energy consumption. In this research, the effectiveness of applying phenolic resin as building materials is evaluated for both winter and summer conditions. The results show that the daytime indoor temperature is 5-8°C lower than outside temperature in summer whereas the indoor temperature can be maintained at 20-22°C in winter..