Design metrics to normalize and compare LCA results in household appliance sector: outcomes from literature analysis

Nowadays, household appliance manufacturers shall adapt their engineering methods and tools to meet environmental concerns. Despite the environmental assessment of products and services is usually carried out based on Life Cycle Assessment (LCA) standardized approach (e.g., ISO14040/14044), numerous assumptions are up to practitioners' discretion, such as functional unit, system boundaries, or allocation method. These choices may lead to a results discrepancy between equivalent studies, even if similar products are considered. The goal of this work is to present a method for determining appropriate metrics (indices) that enable designers to compare the findings of LCA analysis carried out in the context of home appliances. The indices refer to the cooker hoods family and they were developed through a systematic literature review. LCA studies carried out from 2006 to 2022 were the basis for the identification of design features and parameters that allow the normalization of results retrieved in different studies. These features served as the basis for the indices formulation, enabling an accurate comparison of appliances from the same family. The application of these indices, according to the results, makes LCA evaluations of cooker hood models with different performances and design factors comparable. Finally, the same approach can be adopted to create a framework and a useful guide to conduct future LCA studies for other household appliance families with the aim to provide a normalization basis to compare product design alternatives.