This chapter explores the thermal behavior of the HOMEDONE lightweight emergency housing system, with particular attention to overheating risk in hot climates. The study combines experimental data, dynamic thermal simulations, and passive strategy modeling to assess and improve indoor thermal comfort without relying on mechanical systems. Several passive measures are investigated—cool materials, shading, natural ventilation, and internal thermal inertia—both individually and in combination, across three representative climates. Results show that natural ventilation and cool envelope strategies are the most effective, but their performance strongly depends on climate and aging conditions. A cost-effectiveness analysis further informs the selection of optimal solutions for emergency deployment. The study highlights the importance of passive design integration to ensure livability and resilience in temporary shelters.