Impact of Envelope Retrofitting Measures on a Building’s Life Cycle Greenhouse Gas Emissions in India: A Case Study

In India, the greenhouse gas emission (GHGE) from the residential stock is projected to increase exponentially over the next decade unless retrofitting measures (RMs) are implemented. Conventionally, RMs are applied to reduce the operational GHGE (OGHGE) of the existing building stock. However, the life cycle GHGE (LCGHGE) perspective is consistently omitted in building codes, thereby, not accounting for embodied GHGE (EGHGE). This study addresses this gap by evaluating the LCGHGE associated with various building envelope RMs. A case study approach has been adopted and is considered as the reference model for application of 63 retrofitting configurations. Each retrofitted configuration has resulted in a distinct retrofitted model accounting for 64 models, which includes the reference model. The primary operational energy has been deduced adopting Indian primary energy factor after end use energy simulation in the DesignBuilder software. Subsequently, the life cycle OGHGE is quantified by utilising Indian GHGE factors, while the life cycle EGHGE is calculated adopting process analysis. 44 out of 63 models projected a LCGHGE saving of 0.08-16.79 tCO2e across 50 years of life, revealing that incorporation of RMs do not constantly yield LCGHGE savings. These findings highlight valuable insights for retrofitting related decision making, policies and guidelines.