This study discusses the significance of the use of non-renewable fossil cumulative energy demand (CED) as proxy indicator in the beverage packaging sector, in order to detect those situations in which companies can benefit from the use of proxy indicators before a full life cycle assessment (LCA) application. Starting from a case study of two milk containers, the objectives of this paper are to assess if the use of this inventory indicator can be a suitable proxy indicator both (1) to decide which is the packaging alternative with the lowest environmental impact and (2) to identify the most impacting process units of the two products under study.The analysis was made according to ISO14040-44. The goal of the comparative LCA was to evaluate and to compare the potential environmental impacts from cradle to grave of a laminated carton container and a HDPE bottle. The results of the comparative LCA obtained with the non-renewable CED indicator are compared with a selection of impact categories: climate change, particulate matter formation, terrestrial acidification, fossil depletion, photochemical oxidant formation. A further analysis is made for the two products under study in order to determine which are the environmental hot spots in terms of life cycle stages, by the means of a contribution analysis.From the comparative LCA, the use of non-renewable CED revealed to be useful for a screening as the results given by the non-renewable CED indicator are confirmed by all the impact categories considered, even if underestimated. If the aim of the LCA study was to define which is the packaging solution with a lower environmental impact, the choice of this inventory indicator could have led to the same decision as if a comprehensive LCIA method was used. The contribution analysis, focusing on the identification of environmental hot spots in the packaging value chain, revealed that the choice of an inventory indicator as non-renewable CED can lead to misleading results, if compared with another impact category, such as climate change.As in the future development of beverage packaging system, LCA will be necessarily integrated in the design process, it is important to define other ways of simplifying its application and spread its use among companies. The LCI indicator non-renewable fossil CED can effectively be used in order to obtain a preliminary estimation of the life cycle environmental impacts of two or more competing products in the beverage packaging sector.