The increasing environmental footprint of the information and communication technology sector calls for innovative strategies for assessing and improving its sustainability. Life Cycle Assessment (LCA) methods are suitable for estimating the negative environmental impacts of products or services. While some LCA methods start to be applied during the engineering of Cyber-Physical Systems (CPS), some challenges remain unresolved. For instance, the energy consumption, and therefore the greenhouse gas emissions, of CPS is influenced by the specific configuration of components in their architecture, as well as by the geographical location where the components are deployed. Also, the skills and efforts required by LCA projects, remain prohibitive to many CPS engineering projects. This paper presents an LCA-based method tailored for CPS that facilitates the analysis of the environmental impact and the comparison of architectural and location variants. Moreover, we have developed a supporting tool that guides the process and automates part of the data collection activity. Through an illustrative case and expert assessment, we have been able to assess the benefits and drawbacks of our proposal. With these contributions, we hope to lower the barrier to adopting LCA practices in CPS engineering projects, both in industry and academia.