Updating the Path to a Carbon-Neutral Built Environment—What Should a Single Builder Do

This paper proposes an extension for feasibility assessment of residential energy (heat and electricity) supply solutions in an operational environment undergoing major changes. In order to improve the life cycle economy of the energy supply, the design has to accommodate technological, economic, and regulatory changes in operational environment over the long time. New elements must be included in feasibility assessments of energy supply to ensure consideration of future economic opportunities and risks. The extended feasibility assessment brings up the profitability of “future proofed” more sustainable solutions with lower risks related to utilization costs and with improved resale value preservation. The findings of systematic literature study were structured and clarified into a decision support matrix to guide the assessment process. The procedure was verified by identifying the optimal energy supply solution for a net-zero energy single-family house in Southern Finland. The verification demonstrated that the procedure provides new insights on the economy and the climate implications of the energy solutions.