New York City officials are exploring a first-of-its-kind project that would cool sweltering subway platforms while recycling excess underground heat to warm nearby buildings during the winter, with one of Manhattan’s hottest stations selected as the potential testing site.
Mayor Zohran Mamdani, Gov. Kathy Hochul, and the Metropolitan Transportation Authority announced Monday that they are partnering on a feasibility study for a thermal energy network designed to lower temperatures on subway platforms while capturing and repurposing the heat generated underground.
If approved, the pilot project would be installed at the Brooklyn Bridge–City Hall 4/5/6 station and the adjacent Chambers Street J/Z station. Officials said it would be the first transit-based thermal energy network of its kind anywhere in the United States.
The study is being launched as the MTA prepares a major renovation of the aging Chambers Street station. Officials said the planned reconstruction presents an opportunity to evaluate innovative ways of addressing the increasingly severe heat that riders experience throughout the subway system.
According to MTA data, the Brooklyn Bridge–City Hall station was among the hottest in the network during the summer of 2025, with average temperatures reaching 96 degrees.
“There are few feelings worse than escaping the extreme summer heat only to find yourself on a subway platform that is even hotter,” Mayor Mamdani said. “We can make our subway platforms cooler and more comfortable while putting wasted heat to work during the winter.”
Under the proposal, heat generated within the subway system would be collected, stored beneath the ground, and then redirected to nearby municipal buildings for heating during colder months. Officials believe the technology could both improve passenger comfort and reduce energy costs.
“For years, New Yorkers have suffered through sweltering summer heat on subway platforms,” Hochul said. “Working with Mayor Mamdani and the MTA, we are harnessing cutting-edge climate technology for a truly cool purpose: making our subway stations tolerable during the summer and heating critical city buildings during the winter.”
Officials said the feasibility study will cost approximately $800,000, while the larger renovation of the Chambers Street station will be financed through congestion pricing revenue.
MTA Chairman and CEO Janno Lieber said the agency is evaluating solutions that have never before been implemented in a U.S. transit system.
“Bringing down the temperature is a real challenge in a century-old system with open entrances and vents everywhere,” Lieber said. “We’re exploring solutions … to make stations more comfortable while helping to reduce energy costs. Everybody wins.”
Officials described the proposal as part of a broader effort by both the city and the MTA to modernize transit infrastructure and better prepare it for rising temperatures linked to climate change.
The announcement also included details of a comprehensive renovation of the Chambers Street J/Z station, which first opened in 1913. Planned improvements include new station structures, replacement of aging tilework, upgraded stairways, and a full restoration of the historic facility.
“Anyone who has stood on a subway platform in August knows that our stations do not just get hot, they turn into underground saunas,” Mamdani said. “And if you, like me, do not know what a summer suit is, and choose instead to commute in a wool one, let me tell you, it’s far from a therapeutic experience.”
The MTA expects to award a contract for the project this fall. If the location is ultimately deemed suitable, design work on the thermal energy system could begin in early 2027.
