The building sector is responsible for about 1/3 of India’s annual primary energy consumption. Among the four phases of a building life cycle, the operation (or use) phase is significant in terms of the total life cycle energy use, followed by the construction phase. As we achieve energy efficiency in the building operation phase, the next focus of improvement is the construction phase consisting of the manufacturing of building materials and on-site construction processes. The initial embodied energy of residential buildings in India represents about 30-40% of the life cycle energy. The relative significance of the initial embodied energy can exceed 50% in the case of low energy buildings or buildings with partial space conditioning or natural ventilation. Of all the environmental sustainability indicators, the embodied energy and embodied carbon emissions are the most relevant indicators in the construction industry. Life cycle assessment (LCA) method is used to measure these indicators, typically as single-point estimate. The results generated using the LCA method becomes less reliable or uncertain when the variability, inherent in the input parameters, is not taken into account. To address this issue, ‘uncertainty analysis’ is done, considering the variability in the input parameters. Examples of uncertainty in building LCA are the use of national life cycle inventory (LCI) data when the data is unavailable for a particular type of building material or a product, discrepancies in the bill of materials or actual bill of quantities, and modelling construction equipment use using average energy use data. The main objective of this study is to identify the design parameters that cause uncertainty in the building LCA results and develop guidelines for arriving at a reliable estimate of Initial Embodied Energy of residential buildings. The scope of the work is limited to low-rise Economically Weaker Section (EWS) and Mid Income Group (MIG) type residential buildings.