The KEMRI randomized controlled trial in Siaya District, western Kenya, tested four modifications to electricity-free housing: reflective cool roofs, improved cross-ventilation, locally made ceiling mats, and no-modification control houses. All intervention houses were completely screened on doors, windows and gutters to prevent mosquitoes from entering. The modifications reduced indoor temperatures by up to 3.3°C and the population of malaria-carrying mosquitoes by up to 77 percent. Lead researcher Bernard Abong'o described the measures as a "mosquito net for the whole house". 85 percent of households expressed their willingness to invest in the adoption and maintenance of these modifications. The study demonstrated the scalability and sustainability of the approach using available local materials. KEMRI is now conducting a larger cluster-randomized trial in Siaya and Kwale districts to assess long-term health, economic and climate benefits. The research illustrates the challenges of passive cooling in hot, humid Africa, where temperatures are rising and millions of new homes will be needed by mid-century.[2][3]