If the Pollard project continues to move forward, Needham’s future middle school could become the third building in town to run entirely on geothermal heating and cooling.
A ground source heat pump system was chosen based on its value over a 25-year period and its alignment with Needham’s sustainability goals — but the decision has already met resistance in the form of Article 97 restrictions and community concerns around the initial cost of installing geothermal.
Currently estimated at $7,098,250, the cost is roughly 2% of the $325.4 million project.
$7 million would cover 125 geothermal wells at an 800-foot depth, along with associated sitework and distribution. As the project moves into detailed design, the cost estimate will change to reflect design refinements said Hank Haff, director of design and construction.
Geothermal was one of four heating and cooling approaches considered for the Pollard project, along with an air-to-water heat pump and electric boiler system, a natural gas condensing boiler and air cooled chiller system, and a ground source heat pump and air-to-water heat pump hybrid system.
All options had to meet Needham’s specialized energy code, which went into effect in 2024. The code requires new construction be consistent with the state’s net-zero by 2050 goals, pushing new construction toward energy efficiency.
The geothermal system would meet code requirements and could be eligible for MassSave program incentives and Inflation Reduction Act tax credits. The federal energy tax credits are non-competitive, meaning school districts do not need to apply for funding, but can instead file for reimbursement after installing the equipment. The cash reimbursement typically covers 30% of project costs — though it can cover up to 50% — and is available to projects beginning construction by Dec. 2034.
A life-cycle cost analysis used cost estimates from Bond Construction’s schematic design for Pollard to compare the initial cost of equipment, replacement and maintenance costs and operating energy costs over 25 years. Compared to the other options, a ground source heat pump system had lower CO2 emissions, energy use intensity and life cycle costs, but a higher initial cost for drilling wells and associated horizontal piping.
The Pollard project team determined the system would offer the best value of the four options over a 25-year period, saving an estimated $4 million compared with natural gas condensing boilers and air cooled chillers, an estimated $4 million compared with a GHSP and air-to-water heat pump hybrid system, and an estimated $6 million compared with an air-to-water heat pump and electric boiler system.
“The Public Services Administration office building has the lowest HVAC maintenance cost and the lowest [Energy Use Intensity] of any public building in town in part because of the geothermal system,” said Haff, referencing Needham’s first building to run on geothermal heating and cooling.
How geothermal heating and cooling happens
Geothermal systems depend on the constant, moderate temperature of the ground (50 to 65 degrees Fahrenheit year round) to reduce heating and cooling demands throughout the year.
The system’s underground pipes are filled with water and antifreeze, with a circulation pump pushing the liquid through a ground loop to keep it moving continuously. A heat exchanger above the ground transfers heat between the ground liquid and the building system, absorbing heat from the ground liquid in cooler months and dispersing heat during warmer months. A heat pump boosts the heat so it can effectively warm the building during cooler months. A distribution system with ducts, vents and radiant piping then delivers heating and cooling throughout the building.
“It is important to note that the geothermal wells have a life expectancy of 50 years or more,” Haff said. “While the internal HVAC equipment in all options will likely need replacement in a normal 20–25-year lifecycle, the geothermal wells and distribution piping will likely continue to be operable for 50 plus years. This will help reduce future operating costs through the full lifecycle of the new Pollard school.”
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