Abstract: In this study, the life cycle cost analysis of single and double slope passive solar still for composite climate of New Delhi has been carried out. The analysis is based on annual performance of energy and exergy of both solar stills. It has been observed that water produced by proposed double slope solar still is cheaper (Rs. 0.28 L-1) than proposed single slope solar still (Rs. 0.33 L-1; Rs. stands for Rupees, an Indian currency). The Energy Pay Back Time (EPBT) for proposed single and double slope solar stills are 1.64 and 1.60 years, respectively.