Low-cost design to cut indoor heat in Latin American cities ^{CEFR B2}

Research published in the November issue of Energy and Buildings examines how simple, low-cost architectural choices can reduce indoor heat in Latin America’s fast-warming cities. The team used computer simulations to test how different building configurations perform under present and projected climate conditions in five major cities: Rio de Janeiro, São Paulo, Santiago, Bogotá and Lima. They assessed energy performance, costs and carbon emissions to identify combinations that keep interiors comfortable while minimising energy use.

Lead author Alexandre Santana Cruz, who holds a PhD in architecture from the Federal University of Rio de Janeiro, reports that widely used construction systems—traditional masonry, fibre cement or clay tiles—combined with expanded polystyrene insulation and single-pane glass represent suitable configurations for climate-resilient buildings in the analysed countries. The researchers classify these options as passive architectural design because they favour natural ventilation, shading and controlled sunlight instead of reliance on heavy air conditioning. The study warns that advanced building technologies can help but their high cost and the carbon emissions from production make them unrealistic for broad use in the region.

Independent architect Karen Carrer Ruman de Bortoli, a professor at the Federal Institute of São Paulo, agreed that low-cost passive measures can reduce heat discomfort and limit dependence on air conditioning. She highlighted correct orientation to sun and wind, walls with greater resistance to heat transfer, ventilated roofs and green spaces. The MORA housing research group at the Federal University of Uberlândia found that homes built under a federal housing programme in a city with a dry, mixed climate often lacked passive design features and left families vulnerable during heatwaves; the group also noted that informal, costly renovations by residents can further weaken housing resilience.

To bridge the gap between design and practice, the researchers propose a free digital tool to generate customised housing designs for local climate and urban conditions. They also stress community engagement, education for new homeowners, renovation guides, worker training and community workshops as practical next steps to improve comfort and reduce energy use without major investment.