New York City, New York state and the Metropolitan Transportation Authority (MTA) are exploring a new way to manage extreme heat in the subway system while putting that heat to useful work elsewhere.
The agencies are launching a feasibility study for a thermal energy network that could cool subway platforms and transfer excess heat underground for use in nearby municipal buildings during colder months.
The study will focus on the Brooklyn Bridge-City Hall 4/5/6 station and the Chambers Street J/Z station complex in Lower Manhattan. If successful, the project could become the first thermal energy network developed within a U.S. transit system.
A New Approach to Subway Heat
Brooklyn Bridge-City Hall is one of New York City’s hottest subway stations. Average summer temperatures at the station reached about 96 F in 2025.
The extreme heat creates an ongoing challenge for passengers and the MTA. While the agency has focused on getting riders onto air-conditioned trains faster, officials are also looking at longer-term solutions that could reduce temperatures on subway platforms.
The proposed system would use radiant cooling to absorb heat from the Brooklyn Bridge-City Hall platform. Officials are also considering whether Chambers Street could be included in the cooling system.
Instead of allowing that heat to go to waste, the system would move it through pipes to geothermal boreholes located beneath an abandoned center platform at Chambers Street.
Storing Subway Heat Underground
The abandoned platform at Chambers Street could provide an important advantage during testing because engineers may be able to install and evaluate the system without significantly affecting passenger areas.
The geothermal system would store heat underground. During colder months, that stored energy could potentially be recovered and used to heat nearby municipal buildings.
This approach would allow one system to address two problems: excessive heat in subway stations during summer and heating demand in city buildings during winter.
Thermal energy networks are already used in places such as hospitals and universities. They transfer heat between buildings or other facilities and can reduce the need for conventional fossil fuel-based heating and cooling.
Chambers Street Renewal Creates an Opportunity
The study comes as New York prepares for a major renovation of the Chambers Street station.
The planned station renewal includes rebuilding structural elements, replacing tiles, improving stairways and restoring other parts of the historic station. The project is being funded through congestion pricing.
Because major construction work is already planned at Chambers Street, officials will also have an opportunity to determine whether thermal energy infrastructure could be incorporated into the station.
Potential Energy Savings
The feasibility study will examine how much cooling the proposed system could provide and whether it could reduce energy costs.
New York City estimates that radiant cooling can be 25% to 35% more energy efficient than traditional air conditioning in suitable applications.
Rather than cooling the entire volume of air, radiant cooling uses chilled water flowing through panels or embedded tubing. Cool surfaces then absorb heat directly from the surrounding space.
For an old subway system with open entrances, ventilation openings and other sources of heat, cooling platforms efficiently presents a significant engineering challenge.
Heat From Trains Adds to the Problem
The Brooklyn Bridge-City Hall station also receives substantial heat from trains operating on the 6 line, which terminates at the station.
That makes the location an important test site for determining whether a thermal energy network can capture and manage heat generated inside a busy subway environment.
The MTA will work with the New York City Department of Citywide Administrative Services, the Mayor’s Office of Climate and Environmental Justice and the Office of the Deputy Mayor for Operations on the study.
The contract for the feasibility study is expected to be awarded in fall 2026. If engineers determine that geothermal infrastructure is practical, design work could begin in early 2027.
A Potential Model for Climate-Ready Transit
The project reflects New York’s broader effort to prepare its transportation infrastructure for increasingly severe heat.
If the study shows that subway heat can be captured, stored and reused effectively, the approach could provide a new model for managing temperatures in other transit facilities.
For New York, the goal is not simply to make subway platforms more comfortable. Officials are examining whether heat that currently creates a problem underground could become a useful energy resource for buildings elsewhere in the city.
