The purpose of this study is economic effect analysis of geothermal system for remodeling of public rental facilities. There are three kinds of economic effect analysis of geothermal system for remodeling of public rental facilities : economic analysis, energy consumption analysis and greenhouse gas emissions analysis. Economic analysis is used for life cycle cost. Life cycle cost(LCC) is the process of making an economic assessment of an item, area, system, or facility by considering all significant costs of ownership over an economic life, expressed in terms of equivalent costs. The essence of life cycle costing is the analysis of equivalent costs of various alternative proposals. Energy consumption analysis is used for ton of oil equivalent(TOE). Greenhouse gas emissions analysis is used for carbon dioxide emissions($TCO_2$). The results are as follows : 1) The $LCC_{15}$ of geothermal system decreases about 2.27% compare with absorption chiller-heater system for urban gas. 2) The TOE of geothermal system decreases about 56.73% compare with absorption chiller-heater system for urban gas. 3) The $TCO_2$ of geothermal system decreases about 55.87% compare with absorption chiller-heater system for urban gas.