A randomized field trial in rural western Kenya, the region most vulnerable to the health impacts of climate change, tested four house modifications: reflective cool roofs, improved cross ventilation, locally made ceiling mats, and unmodified control houses[1]. All intervention houses had complete netting of doors, windows and hatches to limit the entry of mosquitoes[1]. Modifications without electricity reduced internal temperatures by up to 3.3 °C[1]. The combination of cool roofs and vector screening most effectively reduced indoor heat, improved thermal comfort, and reduced malaria mosquito density by up to 77%[1]. The study was carried out in collaboration with the Liverpool School of Tropical Medicine, Charité – Universitätsmedizin Berlin, Università degli Studi di Milano and Habitat for Humanity International, with funding from the Wellcome Trust and SeaFreight Labs[1]. The results were published in Nature Medicine on January 5, 2026[1].