The decision on most eco-efficient production scheme for producing customized products is highly time consuming and error-prone as it depends on several factors most notably the geographical locations, legal requirements, materials characteristics and process related parameters. Furthermore, the planners must be experienced with the simulation tools as well as related terminologies, environmental laws and standards to conduct precise assessments. The limited functionalities of decision making tools as well as non-automated exchange of information and data, absence of environment related knowledge and non-standardized interfaces between the simulation tools and ERP/PLM systems make planners incapable of reaching quick decisions on eco-efficient choices. This paper proposes a web-based inference system seamlessly connected with the LCA simulation tools and legacy systems. The web-based software automatically analyzes the input on manufacturing alternatives to produce customized products and generates automatically the corresponding LCA simulation models. These models can be used inside LCA tools.