Towards sustainable housing in Tunisia: Optimizing passive and hybrid ventilation strategies across various climatic zones

In response to the increasing demand for energy-efficient housing in Tunisia, this study applies Design Builder simulations to investigate the effectiveness of passive and hybrid ventilation strategies in a representative dwelling situated in three distinct climate zones: temperate Mediterranean (Tabarka), Mediterranean (Sousse), and hot arid (Tozeur). The scenarios explored include optimized natural ventilation (based on window operation, scheduling, and opening temperature), phase change materials (PCMs), a solar chimney, reflective roofing, and a hybrid ventilation system, all evaluated against a conventional mechanical ventilation baseline. Results indicate that optimized natural ventilation is particularly effective, reducing annual energy consumption by 38.4–42.6 % and lowering CO₂ emissions by 6–10.8 %, depending on the region. While the hybrid ventilation system increased energy use by 14–16 %, it significantly improved thermal comfort, as reflected by enhanced PMV and PPD indices and by raising the proportion of comfortable occupied hours to nearly 76 %. Economically, optimized natural ventilation achieved the greatest savings, reaching 42.96 TD/m² in Tozeur, compared with 28.71 TD/m² for the hybrid approach. These findings highlight the substantial potential of climate-responsive passive and hybrid strategies to advance sustainable, cost-effective, and environmentally responsible residential buildings in Tunisia.