The conceptual model of the Subjective Emotional Aspect of Valuation (SEAV) develops guidelines for the measurement, control, and prediction of the emotional response to projects. The SEAV is defined as a valuation done by the end-user, and is expressed along a desirability scale ranging from “completely unacceptable” to “improvement beyond this point has no additional value”. The essence of this paper is the application of decision-making theories to project acceptance problems; it presents a conceptual model, or a “box for thinking”. The theoretical framework of this document includes theories and findings from various fields of knowledge. The main difference of the SEAV model from alternative findings is that the Reference Point measures are included in the list of parameters. Anecdotal evidence suggests that the overwhelming majority of problems involving the emotional acceptance of a project revolve not around its implementation, but the product or service design. The research described in this paper suggests an additional parameter that substantially affects a project’s vitality, especially in the case of projects with a wide stakeholder base: it is the stakeholders’ SEAV of the project that is important. The conceptual model of SEAV provides tools to measure, to predict and to evaluate the stakeholders’ emotional valuation in the early stages of the project, beginning at product or service design. Although this research should be developed further, it already provides useful tools for use in project management practice, and appears applicable to different areas of management.