Assessment and Optimization of Passive Thermal Comfort Strategies for Low-Cost Housing in Eastern Kinshasa, Democratic Republic of the Congo

Low-cost housing in Kinshasa is highly vulnerable to indoor overheating because of the hot and humid tropical climate, the widespread use of poorly performing construction materials, and limited access to mechanical cooling. This study assessed and optimized affordable passive thermal comfort strategies for a representative low-cost masonry dwelling in eastern Kinshasa, Democratic Republic of the Congo.

A reproducible parametric building-performance simulation workflow was développes to investigate the effects of roof construction, ceiling insulation, natural ventilation, secure night-time ventilation, solar shading, building orientation, and opening configuration. A total of 288 design configurations were evaluated under climatic conditions representative of N’djili and N’sele. The best-performing solutions were subsequently examined through a robustness and sensitivity analysis involving 5,000 parameter variations.

The optimal configuration combined a light-coloured roof, a ceiling with 25 mm insulation, secure night-time ventilation, a 0.75 m roof overhang, and an optimized building orientation. In N’djili, this solution reduced the annual number of hours with indoor temperatures above 30 °C from 2,740 to only 12 hours, corresponding to a 99.6% reduction. In N’sele, the same configuration reduced overheating from 2,777 to 85 hours per year, representing a 96.9% reduction.

These results demonstrate that a carefully optimized combination of affordable passive measures can almost eliminate severe indoor overheating in low-cost housing without mechanical air-conditioning. The proposed workflow provides a reproducible scientific basis for climate-responsive housing design, construction guidance, building regulations, and future sustainable housing programmes in Kinshasa and other tropical African cities facing similar climatic and socioeconomic constraints.