When the city water was heated for the optimum use of unused energy, the energy flows and losses were calculated and evaluated to improve the value of heated water systems at dwelling side. To obtain this purpose, it was simulated on heat flows under two conditions like with heat pumps or not and calculated the energy sayings. Furthermore, recycling water system was suggested for enhancing the value of heated water system. From this results, the energy flows without heat pumps showed that it was 3-4 percents of heat losses from pipes, 62 percents of energy savings from hot water uses and 34 percents of unutilized heat. When the heated water system adopt the recycling water system at dwelling side, it was improved 12 percents of total energy sayings.