Eco-design strategies for household cooking appliances via life cycle assessment and Delphi study

Domestic cooking devices have truly profound sustainable design challenges across high energy use, dependency on critical raw materials, and poor management at end of life. Recent studies failed to systematically convert environmental diagnoses into prioritized design options for a wide range of cooking technologies. This study bridges this gap through an integrated mixed-methods framework combining a cradle-to-grave Life Cycle Assessment (LCA) with a three-round Delphi expert panel. The LCA, conducted for gas, biogas, induction, and halogen hobs under different scenarios adopted a per-meal scalable functional unit while reporting full lifecycle impacts, enabling both granular and systemic comparisons. Results from the LCA revealed pronounced environmental trade-offs: induction hobs exhibited the lowest carbon footprint (1619 kg CO₂-eq) and energy demand (19,368 MJ), yet incurred the highest human toxicity (0.0011 CTUh) and resource scarcity impacts due to electronics and rare-earth components. Halogen hobs offered a balanced profile, approaching 90 % of induction’s efficiency with significantly lower material toxicity. Biogas systems reduced GHG emissions by 59 % compared to conventional gas hobs but required 40 % more maintenance. Monte Carlo simulation (10,000 iterations) confirmed the statistical robustness of these rankings, while sensitivity analysis highlighted that end-of-life scenarios had minimal influence on global warming potential (<0.5 % change) and industrial waste (5–7 % variability). Based on the iterative involvement of experts, the 15 circular design strategies were developed and ranked; like (1) ferrite-core induction coils to avoid the use of rare earths, (2) self-regulating biogas nozzles for optimal combustion, (3) retrofit biogas conversion modules for dual-fuel operation, (4) photocatalytic biogas purifiers to mitigate toxic emissions, (5) graded porosity 3D-printed housings for reducing weight, (6) AR-supported maintenance interfaces and (7) closed-loop aluminum casting to reduce the consumption of virgin material. These strategies combined address the main lifecycle hotspots (material substitution, smart operation and design for disassembly), providing manufacturers with a generalizable roadmap. This study highlights that a context-driven, strategy-based redesign rather than incremental upgrades is needed to adapt household cooking technologies to circular economy principles. By converting quantitative environmental profiling into expert-validated design interventions, this paper demonstrates a decision-support framework that can be reproduced flexibly to inform sustainable innovation of appliances. • Conducting a comprehensive cradle-to-grave LCA comparing four hob technologies: gas, biogas, induction, and halogen. • A mixed-methods applied of quantitative LCA with qualitative expert Delphi panels for bridging a critical research gap. • A Monte-Carlo simulation has been applied to normalize the data and approve the reliability of results. • Sensitivity analysis of End-of-life management scenarios including landfill vs recycling. • Prioritizing 15 expert-validated circular design strategies based on the LCA to mitigate environmental overall impacts of the products.