Why are low-income neighborhoods hotter in the first place?
Low-income communities often have far less green space and tree cover, which directly makes them hotter. A study in Philadelphia compared two neighborhoods with different social vulnerability levels and found that the low-vulnerability (wealthier) block had nearly 50% tree and grass coverage, while the high-vulnerability (poorer) block had only 0.02% — a 2,500-fold difference [6]. This lack of greenery means less shade and less cooling from evaporation, so these areas absorb and retain more heat.
This pattern is not unique to the U.S. In Bangkok, the urban heat island can make the city up to 7°C hotter than surrounding areas, and low-income communities suffer the most because they have the least green space — Bangkok has only 3 square meters of green space per person, one of the lowest in Asia [7]. A global analysis of 81 U.S. cities found that cooling centers (air-conditioned public spaces) are more likely to be located in socially vulnerable areas, but even then, access is extremely limited — in Atlanta, only 0.01% of the population lives within a half-mile walk of a cooling center [4].
Even when cooling exists, can low-income residents afford to use it?
Having air conditioning does not mean being able to use it. A 2025 community survey in Dallas found that while 94% of low-income residents had home air conditioning, nearly half (47%) limited or avoided using it because of electricity costs [1]. This is a clear example of 'energy poverty' — the infrastructure exists, but the financial barrier makes it ineffective. The same survey found that only 37% of residents knew about resources to help with power bills, and only 42% knew where the nearest cooling center was [1].
This financial squeeze is compounded by other costs. In Austin, Texas, low-income residents interviewed in 2021 listed electricity cost and power outages as major barriers to staying cool, alongside a lack of trees, shade, parks, and pools [8]. In India and Austria, low-income households reported that they simply cannot afford to modify their homes (e.g., adding insulation or better building materials) to cope with heat, leaving them to 'accept unfavourable thermal conditions' [10]. The economic burden is global: a 2022 study estimated that extreme heat has already cost the poorest regions 6.7% of their GDP per capita per year, compared to only 1.5% for the richest regions [9].
What does this mean for health and survival?
The higher temperatures and lack of cooling resources translate directly into more illness and death. A 2025 study of California urban areas found that residents in census tracts with high urban heat island intensity had a 22% higher rate of heart attacks (acute myocardial infarctions) compared to those in low-heat areas, after accounting for pollution and other factors [2]. The same study showed that tracts with more Hispanic, Black, and American Indian residents had higher predicted heart attack rates [2].
The scale of the problem is enormous. A modeling study of London estimated that the urban heat island effect alone caused 399 excess deaths during the summer of 2018, representing about 5,000 years of life lost, with social costs estimated at £987 million (over $1.2 billion) [3]. While this study did not break down deaths by income, the authors note that heat-related mortality disproportionately affects older adults and those with chronic conditions — groups that overlap heavily with low-income populations [3]. Across all the studies reviewed, the consistent finding is that low-income communities contribute the least to the urban heat island (through less energy use, fewer cars, etc.) but suffer the most from its effects [7][9].
About These Sources
This answer is built on 10 peer-reviewed studies — published from 2022 to 2026, 4 from 2024 or later, 6 in Q1 journals, collectively cited 319 times — selected as the most relevant from 10 studies that passed quality screening, drawn from 59 papers retrieved from a database of over 500 million.
Sources used in this answer
Heat Vulnerability and Community Resilience: A Survey Analysis in Dallas, Texas.
A 2025 survey of 78 low-income residents in Dallas found that 47% limited air conditioning use due to electricity costs, and only 42% knew where the nearest cooling center was, showing that financial barriers and lack of awareness constrain heat adaptation despite widespread AC access.
The effect of urban heat island intensity on the rate of emergency department visits for acute myocardial infarctions
A 2025 study of California census tracts found that residents in areas with high urban heat island intensity had a 22% higher rate of heart attacks, with higher rates in tracts with more Hispanic, Black, and American Indian residents.
The mortality and associated economic burden of London's summer urban heat island effect: a modelling study
A 2025 modeling study of London attributed 399 excess deaths and 5,000 years of life lost to the urban heat island effect in summer 2018, with social costs estimated at £987 million.
Examining the Optimal Placement of Cooling Centers to Serve Populations at High Risk of Extreme Heat Exposure in 81 US Cities
A 2023 analysis of 81 U.S. cities found that cooling centers are located in more socially vulnerable areas on average, but access is extremely limited (e.g., 0.01% of Atlanta's population within a half-mile walk), and centers are less accessible to adults aged 65+.
The Distribution and Accessibility of Cooling Resources in Low-income Communities: Comparative Analysis of Beijing and Los Angeles
A 2025 comparative study of Beijing and Los Angeles found that low-income areas have limited cooling infrastructure, higher land surface temperatures, and greater urban heat island intensity, reflecting systemic environmental injustices.
Urban Microclimate, Outdoor Thermal Comfort, and Socio-Economic Mapping: A Case Study of Philadelphia, PA
A 2023 study of Philadelphia found that a low-vulnerability block had nearly 50% tree and grass coverage, while a high-vulnerability block had only 0.02%, directly linking lack of greenery to higher heat exposure in low-income areas.
Unequal and unjust: The political ecology of Bangkok’s increasing urban heat island
A 2023 political ecology study of Bangkok found that the urban heat island can reach 7°C, with low-income communities most vulnerable due to minimal green space (3 m² per person) and political-economic processes that prioritize developers and car use over equitable cooling.
Heat vulnerability of Latino and Black residents in a low-income community and their recommended adaptation strategies: A qualitative study
A 2023 qualitative study of 18 low-income Latino and Black residents in Austin, Texas, found that heat caused physical and mental health problems, and residents identified lack of trees, shade, parks, and electricity cost as key barriers to staying cool.
Globally unequal effect of extreme heat on economic growth
A 2022 global study found that anthropogenic extreme heat has cost the poorest regions 6.7% of GDP per capita per year (1992-2013), compared to 1.5% for the richest, showing how heat inequality drives global economic inequality.
Low-income residents' strategies to cope with urban heat
A 2022 study of low-income households in India and Austria found that residents lack agency and resources to adapt their homes to heat, forcing them to accept unfavorable thermal conditions, with cheap building materials limiting protection, especially at night.