gLoria Gellot, 79, sits carefully on a kitchen chair in front of her only air conditioner, massaging her knees. She hung a sheet in the doorway to keep fresh air in the kitchen and drew shades to block out the sun — already blazing in May — from her second-floor New Orleans apartment. Her house was severely damaged by Hurricane Ida in 2021 and heat is leaking from the gutted walls.
“It’s hot here,” she said. “I don’t need to go out in the sun. I get a tan indoors.
Gellot’s stuffy apartment is not only uncomfortable; it’s dangerous. Extreme heat was linked to some 11,000 deaths and 120,000 emergency room visits last year. Heat injuries don’t just happen in sunny fields: elderly people like Gellot who live alone and can’t escape stuffy, poorly insulated homes are among those most at risk.
Conventional wisdom and public policy have long assumed that no matter how intense the heat, air conditioning will be enough to keep people safe. But the record temperatures of recent years are shattering this myth.
“The home environment can actually be a significant risk in itself,” said Jaime Madrigano, a public health researcher at Johns Hopkins University. “We see during extreme heat events that more people die at home than in other types of places. They are unable to get to the hospital.
Houses hit by storms like that of Gellot are not sufficiently insulated. Power grids stumble and fail during periods of high demand. And many cooling systems simply aren’t powerful enough to cope with the rising heat. Some experts have begun warning of the looming threat of “Heat Katrina” – a heat event with mass casualties. A study published last year modeling heatwave-related power outages in different cities showed that a two-day power outage in Phoenix could result in the deaths of more than 12,000 people.
Last summer, Madrigano led a team of researchers who installed temperature sensors in the rooms of 70 volunteers in the low-income Gellot neighborhood, primarily Black Ninth Ward. In the midst of New Orleans’ hottest summer on record, “about a quarter of our (average) readings are above 80F (27C),” she said. About half of the homes exceeded 80F at some point during the day.
There is no single standard for safe indoor temperatures. However, with each degree of temperature increase, participants reported more symptoms of heat illness: dizziness, headaches, nausea, weakness and fatigue.
“It’s almost hotter inside than outside,” reported one participant, who said she still had an $800 energy bill. Another participant described being “just overwhelmed” and taking showers to stay cool. “I can see how this will happen in the years to come,” he added.
Most attendees, like Gellot, had air conditioning, Madrigano said. “On the surface it seems great,” she said, but it reveals that air conditioning simply isn’t enough in increasingly hotter cities.
Cooling systems can’t keep up
“The types of (cooling) systems we sold 10 years ago are not able to keep up with weather conditions,” said Simi Hoque, an architectural engineer at Drexel University who studies how the design of buildings contribute to indoor heat.
As temperatures rise, air conditioners — which work by drawing in indoor air, heating it via a compressor and then exhausting that heat outside — have to work exponentially harder. Keeping a house stable at 75F requires about 30 percent more energy when outdoor temperatures rise from 95F to 98F, according to Texas A&M climatologist Andrew Dessler.
Some older AC units simply cannot meet these demands. Even if they can, many residents can’t afford higher energy bills. The surge in energy demand is straining power grids: in 2021, a heat wave in the Pacific Northwest triggered repeated power outages, which left at least 600 people dead.
Many buildings — especially those in cooler northern U.S. cities — are simply not designed or weatherproofed for the new heat, Hoque said. She became interested in indoor heating while working on an air quality study in Philadelphia, where she lives.
“When we talked to family members, (heat was) the problem that kept coming up,” she said. Participants told him, “We can’t be in our upstairs rooms during the summer unless we have the window open, and we only have one window, so everyone sleeps in the same room,” remembers Hoque.
Hoque said there are many gaps in indoor heat research and she uses wet-bulb measurements, which take into account humidity as well as temperature, when assessing indoor conditions.
Extreme heat and redlining
Extreme heat disproportionately affects communities of color.
Black and Hispanic communities, in particular, are more likely to live in urban heat islands, where asphalt traps more heat than greener and generally wealthier neighborhoods. This disparity is a legacy of decades of redlining and other racist housing policies. People most exposed to indoor heat “also tend to have fewer resources to be able to afford things like air conditioning or fans,” Hoque said, and these factors have serious public health implications: in New York, according to state data on After last year’s record heat, Black residents are twice as likely to die from heat as their white counterparts.
Although the heat is not fatal, it is damaging. Heat Triggers respiratory distress, acute cardiovascular events, sleep disturbances and cognitive impairment – in other words, heat makes it difficult to breathe, sleep and think.
“It’s unbearable,” said Dee Dee Green, an organizer in the Hollygrove neighborhood of New Orleans, a low-income, mostly black neighborhood bordered by freeways. Green said his air conditioning has broken down for the past three summers in a row. She suspects this is due to the unit being overworked.
Raymond Sweet, another organizer who works near Green, said warmer indoor temperatures led to compounded costs for low-income households: “You used to put out a banana for a week. Now things get worse in two or three days. That in turn requires more trips to the grocery store and more money spent on groceries that spoil in hot kitchens, he said.
The surrounding trees keep Sweet’s house cool, but elsewhere the neighborhood gets “too hot to even walk around,” he said. He teamed up with his neighbors to plant trees and pressure the city to build bioswales, which have the added benefit of reducing flooding.
Many low-income Americans are eligible for federal energy assistance funds to help cover the costs of air conditioning. And after last summer’s deadly heat, New Orleans policymakers enacted an ordinance requiring landlords to provide enough air conditioning to keep rooms at 80F or lower. But the program has received no funding, giving program administrators limited means to implement it.
Hoque worries what it will take for policymakers to take the risk of indoor heat seriously enough. “Changes are only made when something bad happens,” she said. For people like Gellot and his neighbors, “the worst has already happened.”
