Journal of Korean Institute of Architectural Sustainable Environment and Building Systems ISSN:1976-6483(Print) 2586-0666(Online) 한국건축친환경설비학회논문집

In green remodeling, the insulation reinforcement is the most common method. The insulation remodeling can achieve higher energy savings at low cost. In this study, economical analysis for old detached house was performed by the insulation type and thickness according to the energy saving level, insulation codes, cost-benefit. In the case of Extruded Polystyrene (XPS) foam insulation, the energy performance and Net Present Value are highest among analysis cases, but the economic feasibility will be lowered because the increase of construction cost is greater than energy cost savings due to increasing insulation thickness. Expendable Polystyrene (EPS) foam Class 1 No. 4, which has the lowest material cost, indicate the fastest simple payback period. However, in the cost benefit analysis considering the cost reduction due to energy saving, the EPS Class 2 No. 4 100 mm indicate highest benefit.