Members of the Town of Southborough Neary Building Committee Sustainability Subcommittee reviewed a life‑cycle cost analysis for the Neary School HVAC systems on Jan. 2 and indicated informal consensus that a ground‑source heat pump (geothermal) best meets long‑term energy and maintenance goals when available incentives are applied.

Arrowstreet and the project’s mechanical engineering consultants presented the report and summarized three systems analyzed: (1) a variable‑refrigerant‑flow system (VRF); (2) a ground‑source heat pump system; and (3) an air‑to‑water heat pump (air‑source) chiller/heating plant (as described in the report). The analysis compared qualitative factors (indoor air quality, thermal comfort, acoustics, service life and ease of maintenance) and quantitative measures (annual energy cost, annual maintenance cost, lifetime replacements, capital investment and a 50‑year payback assessment).

The presenters noted the project’s energy use intensity (EUI) target of about 25 as the threshold for a “net‑zero” building and cited Mass Save program requirements tied to that target. With the Mass Save state incentive and an additional federal tax incentive that applies only to the ground‑source option, the consultants reported that the ground‑source system produces an immediate net present benefit in their 50‑year assessment; without those incentives, no option returned payback within the 50‑year window. The presenters also noted a separate Mass Save commissioning verification incentive of about $150,000 available after 12 months of monitoring and reporting.

On qualitative points, the presenters said all three systems would deliver acceptable air quality and comfort, but differences arise from delivery method: systems that use displacement ventilation generally ranked higher for indoor air quality and thermal comfort than overhead supply systems. The VRF option was described as having more in‑space mechanical components and higher routine maintenance needs (washable filters and multiple terminal units), while the ground‑source and air‑source options would use VAV terminal units with less per‑room filter maintenance. Consultants said ground‑source systems may incur fewer exterior maintenance demands because key plant equipment is indoors rather than exposed to New England weather.

The report included capital estimates that were presented as numeric values (the presenter said “83 for a VRF, which is the least expensive, and 120 for the ground source”), and the team explained those capital figures were reduced somewhat from earlier estimates after updated tonnage and design development. The transcript did not specify currency units or whether those figures represent thousands, millions or another unit; the presenters compared totals on both a per‑square‑foot and full‑project basis. The consultants also noted an earlier modeling change that reduced heating capacity to about 200 tons and said the geothermal well estimate in earlier materials was 60 wells at roughly 4.5 tons each drilled to about 650 feet, though one speaker briefly referenced a differing well‑count figure during the discussion; the transcript shows that the exact final well count required remains to be confirmed in final design.

Committee members discussed programmatic implications and future expansion. One member raised the possibility of future district geothermal connections (a district system in Framingham was cited as an example), and consultants said connecting multiple buildings could sometimes reduce overall well counts where uses complement each other, but that two separate school plants would likely remain distinct and that distance and piping runs could make sharing a field impractical.

Several subcommittee members characterized the group as broadly supportive of proceeding with a ground‑source approach, subject to confirmation of incentives and final design details. A presenter and a member noted that a formal selection or vote would typically occur at the full Neary Building Committee (NBC) rather than at this subcommittee; one speaker said the subcommittee should vote to direct Arrowstreet and the design team to proceed with geothermal design work, while another said no formal decision is recorded until the full NBC votes.

No public commenters raised substantive items during the public comment period, and the meeting concluded with a motion to adjourn. A roll call was taken; one member, Chris (committee member), recorded “Aye,” and the meeting adjourned at 1:37 p.m.

Next steps recorded in the discussion: Arrowstreet and the design team will produce a concise summary of the LCCA for the full NBC and continue schematic design work, incorporating final well counts and incentive verification steps for commissioning and post‑occupancy monitoring.