It was proven that the heating way with low temperature water has many advantages through the comparison of the GSHP radiant floor heating system with PCM and other heating modes.Besides the floor radiant heating system with low water and electricity were also compared from the exergy consumption in this paper,it was demonstrated that the radiant floor heating with low temperature water is the optimum.Also the paper had analyzed the influences of water supply temperature,phase transition temperature and phase change radius,filling amount of PCM and coiled pipe spacing.The author compared this heating mode with the mordern heating modes with electricity from the economical aspects.The results show that its anhual operation cost is less then 1/3 of the heuting with electricity.