Residential-IST: A web-based decision-support tool for bridging knowledge gaps in performance-driven residential building design and retrofitting in Istanbul, Türkiye

• Residential-IST is an open-access web-based decision support tool. • It relies on performance-driven design and interactive data visualisations. • It serves high-performance housing design and retrofits with intuitive user flow. • The design space is made from parametric and multiple-criteria decision analyses. • Study bridges the knowledge gap in supply and demand sides of residential sector. This study proposes Residential-IST to bridge the gap between residential building design, retrofitting, and performance, facilitating effective communication between residential owners (demand) and architects (supply). This web-based decision support tool is designed to inform target decision-makers and enhance decision-making. Residential-IST advances access to multi-objective design solutions by integrating a feedback loop that aligns with early design exploration and iteration principles. The proposed tool employs a workflow that addresses the gap between the information required for transitioning from a conservative to a performance-driven approach and the accessibility of that information by incorporating: i) a computational performance-driven design support method that systematically explores and analyses the design space to identify optimal solutions, and ii) an interactive visualisation method that provides rapid, constructive feedback to decision-makers through an easy-to-use interface, covering a broad design space derived from this approach. The proposed workflow is contextualised for residential building design and retrofitting in Istanbul. This study discusses the potential of this first open-access, energy- and cost-based web tool to facilitate informed decision-making for novice architects and residential owners in Istanbul as well as throughout Türkiye.