The decisions made during the preliminary design phases considerably impact the development of a product's lifecycle, acting on its environmental performance, cost, and duration of its realization. However, the lack of relevant information during these phases does not allow for the accurate evaluation of design solutions. In addition, it generates schedule delays and overruns in the budget allocated to developing a given solution. In this perspective, the present work aims to assess the accuracy of the behavior models used for exploring solutions during the embodiment phase. This was based on two measures of different nature, namely objective accuracy, which is evaluated by referring to real prototyping of a given solution, and the subjective accuracy measure, which allows to the expression of the degradation of the first measure in relation to the reference point. This combination will lead to a measure that can be generalized on all the design space. In a second step, the current work suggests an estimation of the effect of these models' accuracy on the proposed solutions' environmental impact. To this end, a sensitivity study was carried out on the input data of the model (design parameters) in order to deduce the effect of the results obtained (performance parameters) on the mass and, consequently, the environmental impact of the solution. In order to highlight the approach adopted in the present study, it was applied to a real industrial case, ultimately leading to the most optimized solution in terms of accuracy and environmental impact.