The aim of this paper is to propose a methodology for supporting decision making in design activities; in case of new projects or retrofitting of existing buildings. A multidisciplinary approach is adopted; involving Real Estate Appraisal and Economic Evaluation of Project and Building Environmental Design. It is proposed a methodology for selecting the preferable solutions among technological options; considering both economic and environmental aspects; in terms of global performance. Assuming the principles of Life Cycle Thinking and Circular Economy focus is posed at the end‐of‐life stage. Attention is paid on disposal costs and residual value as relevant items enable to orient investment decisions. This is done through an approach for quantifying environmental indicators related to Life Cycle Assessment (Standard ISO 14040:2006); and economic indicators adopting the Life Cycle Costing (Standard ISO 15686:2008). The paper proposes a conjoint “economic‐environmental indicator”. An application of Global Cost calculation is illustrated; including monetized environmental impacts (Embodied energy and Embodied carbon); disposal/dismantling costs and residual value. The result of the Global Cost calculation is expressed through a “synthetic economic‐environmental indicator” in order to select; between two different technologies; the most viable solution for a multifunctional building glass façade project; in Northern Italy. The study demonstrates that the initial investment decisions depend on the design solutions; since the early stages; related to the whole building life cycle considering conjointly the construction‐management phases and the end‐of‐life stage.