Abstract: “Different types of compound radiant floor heating systems are used in residential buildings and their thermal and economic performance varies largely by many factors. One of the most influential factors on performance of a system is envelopes insulation. The aim of this study was to investigate the effect of insulation in thermal and economic performance of a radiant floor heating system. Using different insulation approaches – poor or no insulation, conventional insulation according to national regulations and with BioPCM boards- heating loads and system sizing's were analyzed and calculated by Design Builder software and system and components were compared in each case. The results showed that the heating loads and component sizes decreased significantly with PCM insulation. As a result, using BioPCM boards for envelope insulation can be considered as an energy and money saving constructing approach for a residential buildings using radiant floor heating system. Due to it’s at least”

Keywords: PCM Insulation, BioPCM, Solar Radiant floor, heating system, Energy conservation, DesignBuilder software, Co2 emission, payback period time