The purpose of this study is to suggest the benefit-cost analysis for photovoltaic system in greenhome. Perspectives of benefit-cost analysis for photovoltaic system in greenhome is participant, non-participant, administrator and nation. This study identifies the cost and benefit components and benefit-cost calculation procedures from four major perspectives : participant, non-participant, administrator and nation. The results of benefit-cost analysis from each perspective can be expressed in a variety of ways, but in all cases it is necessary to calculate the net present value of photovoltaic system impacts over the lifecycle of those impacts.