Bringing the Underground Heat: The Science Behind Smith’s Geothermal System

With the final borehole dug on September 11, 2025, Smith College is well on its way to completing its intricate geothermal heating and cooling system. 40% of the campus is already benefiting from the system.

“It's a way for a campus like this to both switch off fossil fuels, electrify the campus, and keep our spaces comfortable,” said Beth Hooker, Senior Director of CEEDS & Sustainability at Smith College.

Photo Courtesy of Lily Serry

Over the past two years, Smith College has dug over 300 new geothermal wells across campus. These wells are part of the complex geothermal heating and cooling system that comprises a significant part of Smith’s goal to be carbon neutral by 2030.

Each 850 feet deep, the wells hold a mixture of water and glycol, an antifreeze solution. By harnessing the heat of the earth’s core, which sits between 48-53 ºF, this fluid is heated and passed through a heat exchanger.

This fluid is then retrieved via a pipe system, which carries it to the surface, bringing underground heat to buildings across Smith’s campus. In the summer, it can also serve cooling purposes by returning this heat to the wells.

Prior to its implementation, a 2017 study on Smith’s campus revealed that over 90% of campus emissions were related to buildings and electricity. “This seemed like the biggest lever to pull,” Hooker said.

Before soil near any academic or residential building was touched, extensive testing for the geothermal project was conducted. A 1,010-foot-deep vertical borehole was placed near the Field House in September of 2019 – a whole two years before the main project timeline. The priority was to test if converting to geothermal energy was even feasible using the existing infrastructure and soil at Smith’s campus.

Using coaxial pipes placed in the borehole, a ground temperature profile was taken, heat was added, and cables were run through the basement of the Field House to test the potential for geothermal energy. The readings came back clear: the temperature data was promising, and the plan was indeed possible.

As the new heating systems are installed on the quadrangle, students are noticing temperature control issues, particularly regarding overheating. Each room has a temperature control system that can be adjusted between 66°F and 70°F.

Lena Morales, a sophomore from Wilson House, expressed her frustrations about the system. “I think the project is worth it, but there should be an on/off switch,” said Morales.

The Geothermal team recently sent out an email to quad residents alerting them that temperature control issues have been resolved and promising to “continue to address these issues as they arise.”

Construction has been completed on the North District and is currently ongoing on both the Quad and Central District. According to Hooker, the plan is on schedule.

By Gwynn Canfield, Lilly Butler, and Lily Mintz

References

McCoy Ebbets, Jan. (2019,  November 6) Experimenting with Geothermal Energy. Smith College https://www.smith.edu/news-events/news/experimenting-geothermal-energy