Regional Cooling and Peak-Load Performance of Naturally Ventilated Cavity Walls in Representative U.S. Climate Zones

Naturally ventilated cavity walls (VCWs) retrofit conventional cavity walls with vents that enable buoyancy- or wind-driven airflow and reduce cooling loads during summer. When closed, they retain the thermal performance of traditional walls. Previous studies evaluated VCWs under steady-state conditions but did not capture regional, transient solar heating effects. This study assesses VCW performance across major U.S. climate types using a transient 3D solar heating model for east-, south-, and west-facing façades in four representative cities. Simulated façade temperatures were validated using published measurements and then applied to a regression-based energy model to estimate cooling load reductions. Results show 30–40% savings for east/west façades and 10–20% for south façades, with monthly reductions exceeding 1.0 kWh/m2 in all regions. On-peak savings (3–7 PM) were at least 1.5× off-peak values, indicating strong peak-shaving capability. Overall, VCWs offer a low-cost, climate-adaptive retrofit strategy that improves façade energy performance and reduces peak cooling demand.