Finding low-cost solutions to hazardous heat
Brazilian settlement residents and U-M collaborators co-developed cooling strategies to protect the world’s most vulnerable populations from excessive indoor heat exposure.
Informal settlements are places of immense ingenuity. While residents may lack regular access to running water or electricity, they build working communities, organizing to provide basic services and meet shared needs. The solutions they are putting into practice, often quickly and cheaply, have a great deal to teach anyone looking for low-cost ways to protect people from dangerous heat.
Pai Ale Padilha had to adapt quickly when he moved to ocupação (Portuguese for occupation) Estrela de Davi, an informal settlement in the Eastern Zone of São Paulo, Brazil. A community of 196 homes, Estrela de Davi’s first houses were precarious structures made of plywood with improvised and unregulated water and electric supplies.
As a religious and community leader, Padilha quickly found rewarding work organizing social services and holidays for the burgeoning occupation. However, after living in Estrela de Davi since the occupation’s founding seven years ago, it has been hard to adjust to the stifling summer heat fueled by climate change. “It’s worse in houses with plywood walls and for those who have low ceilings that trap the heat,” he said through a translation by Ana Paula Pimentel Walker, associate professor in Urban and Regional Planning at Taubman College.
“In the summer or on hot days, it feels like your house is going to catch on fire.”
Padilha and other Brazilian partners are collaborating with Pimentel Walker and other University of Michigan scholars on a participatory-action research project investigating affordable solutions to hazardous indoor heat in informal settlements, funded in part by a seed grant from The Center for Global Health Equity (CGHE).
Inequitable exposure to hazardous heat
Pimentel Walker connected with housing movements during her younger years in Brazil, where she grew up.
After becoming faculty at Taubman College in 2013, she sought to share that passion for housing access with architecture students, and reached out to members of the Union of Central Popular Movements seeking opportunities to partner with them. In the years that followed, U-M students and faculty have collaborated to provide mapping, surveying, funding, and landscaping services for informal settlements.
Many places, including Padilha’s community, have seen temperature spikes in recent years, and the effects reach far beyond discomfort. In homes built without heat-resistant materials or cooling in mind, they are even more severe. In these settlements, indoor heat harms both physical and mental health, and its consequences reach into the home itself. As Ana Morcillo Pallarés and Jonathan Rule, associate professors of architecture and São Paulo research collaborators, explained, elevated indoor heat can exacerbate physiological and psychological strain, increasing irritability, anxiety, sleep disruption, and the risk of domestic violence and interpersonal aggression.
CGHE Impact Scholar and clinical psychologist Érinn Cameron studies the impacts indoor heat has on anxiety and depression levels on women. She noted that in the case of Brazilian occupations, women are more likely to spend significant amounts of time indoors performing chores that generate heat,like cooking or laundry.
“Imagine you’re already exhausted from chores, maybe you’re pregnant, and you’re not getting sleep,” Cameron said. “Your children are crying because they’re hot. What I hear from women is, ‘I’m going to lose my mind.’”
Adults aren’t the only ones affected. In 2024, children were sent home from São Paulo schools due to excessive heat. In Ocupação Anchieta, a young informal settlement where Pimentel Walker has collaborated since 2016, students returned to sweltering homes.
“Extreme temperatures make these unequal patterns of urbanization even worse, with serious consequences for health and education,” Pimentel Walker explained. “Heat has become one of these extreme weather events that lowers life expectancy and interferes with the ability to finish homework or study for college entrance exams because it's too hot to focus.”
