Jennifer and Eric Mauchan live in a Cape Cod-style house in Framingham, Massachusetts that they’ve been cooling with five air conditioners. In the summer, the electric bill for the 2,600-square-foot home can be $200.

In the winter, heating with natural gas is often more than $300 a month, even with the temperature set at 65 degrees Fahrenheit (18 degrees Celsius).

“My mom, when she was alive, wouldn’t come to our house in the wintertime,” because it was too cold, Eric Mauchan said.

But beginning Tuesday, their neighborhood will be part of a pilot climate solution that connects 37 homes and businesses with a highly-efficient, underground heating and cooling system. Even taking into account that several of the buildings will be switching from natural gas to electricity, people are expected to see their electric bills drop by 20% on average. It’s a model some experts say can be scaled up and replicated elsewhere.

“As soon as they told me about it, I bought in 100%,” said Jennifer Mauchan, who works in finance, remembering her first meeting with representatives from Eversource, the gas and electric utility that installed the system. “From a financial perspective, I thought that it was a very viable option for us.” She cited lower greenhouse gases that cause climate change as an important factor in the decision.

Gina Richard, owner of Corner Cabinet, a kitchen and bath cabinet showroom in Framingham, said she felt “pretty lucky” to be part of the project. She currently uses two air conditioners and two heaters and looks forward to replacing all that with a single system. Richard said she was told she could see her winter heating bill of $900-1,000 go down by as much as a third, which she said would be “amazing.”

The Framingham system consists of a giant underground loop filled with water and antifreeze, similar to the way gas is delivered to several houses in a neighborhood. Water in the loop absorbs heat from underground, which remains at about 55 degrees Fahrenheit (13 degrees Celsius) all year.

Households have their own heat pump units that provide heating and air conditioning, installed by the utility. These take heat from the loop, spike the temperature further, and release that heat as warm air into the homes. For air conditioning, heat is extracted from the home or business and released into the Earth or transported to the next home.

The energy sharing works best when some buildings are drawing on heat while another needs it, the way a grocery store needs to keep its cases refrigerated even in winter.

Other networked geothermal projects exist in the U.S., including the Texas community of Whisper Valley and Carleton College in Northfield, Minnesota. Eversource says this is the first utility-led installation in the U.S. If it works, that could be important because an individual homeowner could not do the digging and drilling necessary to create a neighborhood system.

Right now, homeowners can buy individual air source heat pumps, which have become common and are efficient. Or they can drill for more expensive, even more efficient ground source heat pumps. Incentives, such as those in the Inflation Reduction Act or local utilities, help lower the price on these, yet the final cost can still be tens of thousands of dollars.

Framingham beat out other communities that applied to Eversource to become pilot sites. The city 20 minutes west of Boston is surrounded by Harvard University and Massachusetts Institute of Technology, plus firms like Thermo Fisher Scientific, Pfizer and Novartis. Eric Mauchan said the proximity of so much advanced technology and a state law requiring that greenhouse gas emissions ramp down to zero by 2050 helped make the community receptive.

Nikki Bruno, vice president for clean technologies for Eversource, also cited the state’s emissions law as a reason for the pilot. It was also “an opportunity from a decarbonization standpoint,” she said, because Eversource has its own net zero goal.

“We’re thinking about, okay, we do this pilot now, how can we scale this into a sustainable business model, into a sustainable program to offer in more locations?” she said.

Jack DiEnna, founder of the Geothermal National & International Initiative, an alliance of industry professionals, said utilities are seeing pressure to address climate change plus incentives to do so. Ground source heat pumps are highly efficient, reduce the electricity demand on the grid and can be installed in regions beyond the reach of gas lines. They also cool homes and release very little in the way of climate pollution compared to traditional heaters and air conditioners.

There is also an equity issue that concerns some in the climate and energy sector. If people who have the means disconnect their natural gas, it could have unequal consequences for people.

It “means that the people who can least afford it are stuck paying for this gas system, this very leaky gas system,” said Ania Camargo, thermal energy networks manager at the Building Decarbonization Coalition, a nonprofit working to eliminate fossil fuels from buildings.

“One of the reasons why I advocate for utilities to be a big part of the solution is because it’s a way to make sure we can do this for everybody.”

Back at the Mauchans’ home, the couple laughs about the accommodations they were making to their old heating system. “I was so mindful of the expense that we would incur if we increased the temperature to, God forbid, 70 degrees in the winter,” Jennifer recalled about letting the house get cold in winter.

They expect their new heat pump to change things. “I mean, we’ll keep our house 71 degrees all year long,” Eric said.

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