Time-dependent performance of residential buildings under climate change: Thermal resilience, seasonal asymmetry and life-cycle carbon design consequences

Residential buildings designed to meet winter-oriented efficiency standards increasingly fail to ensure safe indoor conditions under summer heat stress and long-term climate change. This study examines residential building performance as a time-dependent trajectory shaped by irreversible structural design choices, not a static outcome of regulatory compliance. Full-scale experimental monitoring of two identical residential test buildings with contrasting envelope mass and floor-ground interaction is combined with prospective life-cycle assessment over a 75-year horizon. The results show pronounced seasonal asymmetry: modest and bounded winter energy penalties associated with thermal mass and ground coupling contrast with gains in summer thermal resilience, with all overheating indicators remaining below threshold values during an extreme heat event. Life-cycle analysis reveals a temporal reversal in carbon performance, with the initially more efficient lightweight configuration exceeding cumulative emissions of the heavier, ground-coupled building after approximately 15-16 years due to increasing cooling demand. These findings demonstrate that structural strategies enhancing passive thermal resilience can also improve long-term mitigation outcomes. The study highlights the design consequences of early architectural decisions and underscores the need for performance-based, time-aware assessment frameworks that integrate resilience and life-cycle carbon considerations.