Tufts administrators are evaluating a potential overhaul of the university’s heating and cooling systems as part of a broader plan to achieve net zero carbon emissions by 2050. The proposal under consideration involves adopting ground-source heat pumps, an all-electric technology that administrators say could significantly reduce emissions while lowering long-term energy costs.
Heating on Tufts’ Medford/Somerville campus is currently supplied largely through a district energy system powered by fossil fuel boilers. Steam and hot water produced at the Central Energy Plant are distributed throughout campus, a process that the university estimates loses roughly 20% of its energy before it reaches individual buildings. Other campus areas rely on independent boilers or standalone systems, many of which serve older buildings with high energy demands.
“Tufts has a goal to eventually decarbonize the energy system of the campus to go carbon-free,” Eric Hines, a professor of the practice in the Department of Civil and Environmental Engineering, said. “Developing a [ground-source heat pump] system is an important part of [going carbon free].”
Ground-source heat pumps, which are sometimes inaccurately referred to as geothermal energy, use the relatively stable temperature of the earth to provide heating and cooling. Rather than generating heat through combustion, the systems use electricity to transfer heat between buildings and the ground.
“A heat pump is a device that is extremely efficient … because it doesn’t generate heat, what it does is move heat from one place to another,” Hines said. “Let’s say the ground is about 55 degrees underground, but if you can extract the 10 degrees from fluid running through the ground, you can actually use that heat to generate really hot temperatures above 100 degrees to heat buildings.”
Because the systems rely on electricity, the emissions benefits of heat pumps depend on how that electricity is generated. Tufts has paired efforts to electrify campus infrastructure with renewable energy sources, including a virtual power purchase agreement signed in 2024 that supports a 7.6-megawatt solar installation in Texas. The project generates approximately 20,000 megawatt-hours of electricity per year and has reduced energy-related emissions on the Boston Health Sciences campus by about 40%.
“Solar energy, similar to wind energy, is a means of producing electricity via renewable resources,” Hines said.
Many of Tufts’ buildings are historic and were constructed before energy efficiency became a design priority, complicating large-scale infrastructure upgrades.
“These buildings are usually really inefficient, and because they are occupied for large stretches of time over the years and they’re so densely populated, the heating and cooling load is really high,” Kelsey Arrington-Podraza, a first-year master’s student in the sustainability program in the Department of Urban and Environmental Policy and Planning, said.
“Making upgrades to these systems can be really challenging because of restrictions with zoning and historic preservation ordinances, and so heat pumps allow them to do a less intensive renovation,” she said.
Arrington-Podraza said electrification plays a central role in reducing campus emissions.
“Because [heat pumps are] electric, you have the opportunity to use cleaner power, and there is no combustion involved and the process is much lower emissions,” she said.
Despite their efficiency, ground-source heat pump systems require significant upfront investment. Dano Weisbord, chief sustainability officer and executive director of campus planning, said that Tufts has completed a conceptual design for such a system but has not committed to construction.
“At this time, Tufts has a conceptual design,” Weisbord wrote in a statement to the Daily. “It provides estimated ranges for cost and savings … this idea remains under active discussion at Tufts.”
Weisbord added that, although operating costs for heat pump systems are generally lower, “the payback tends to be long — more than ten years,” due to the high cost of conversion and the scale of campus infrastructure.
The long-term benefits could still be substantial. Ground-source heat pumps could reduce energy losses during distribution from approximately 20% to as low as 4%–6%, decreasing emissions and operating costs over time. Federal incentives available through the Inflation Reduction Act may also help offset initial costs and accelerate implementation.
Lower campus has emerged as a potential starting point for implementation because of deferred maintenance and cooling needs.
“When you install ground-source heat pumps, you also get cooling as part of the deal,” Hines said, adding that upgrades can be coordinated with other necessary infrastructure work rather than addressed incrementally.
Arrington-Podraza said student involvement would help spur administrative support and secure funding for these initiatives.
“It’ll be really helpful in general, in making a case for the university to pursue these specific upgrades,” she said.
“It begins with curiosity and it begins with finding people who have similar interests, and then I think opportunities start to unfold,” Hines added.
