Edinburgh Napier University

  The European legislative landscape on sustainability is steadily growing to meet objectives to reach net zero targets by mid‐century. In this context, companies and manufacturers may soon be legally required to provide quantification of the environmental impact of their products and services. A key challenge is applying a consistent and robust methodology that ensures comparability between assessments made by different companies, as there is still fragmentation among environmental impact reporting methodologies. The objective of this study is to analyze and compare the results of two different methodologies for the calculation of the embodied carbon in lighting products using the cradle‐to‐grave approach. One is the globally known life cycle assessment (LCA) method, and the other is Chartered Institution of Building Services Engineers Technical Memorandum 65's (TM65) mid‐level calculation methodology, which has been specifically tailored to building services. The two were applied to six different luminaires to evaluate their differences. Results show that the values of the embodied carbon calculated with TM65 are higher than those calculated with LCA and that the weight of the products plays a crucial role in creating discrepancies between the two methodologies.