Lexington School Building Committee confirms hybrid geothermal heat pump as preferred system

LEXINGTON — May 12, 2025 — Lexington School Building Committee confirms hybrid geothermal heat pump system for new high school. The committee unanimously backed Option 3 — a hybrid combining full geothermal heating with air source cooling — after unanimous recommendations from the town's Department of Public Facilities, Program Planning Committee, and Sustainable Lexington. Financial consultant Mark Sandin presented life cycle modeling showing the hybrid system producing roughly $91 million in projected positive cash flow over 30 years compared to a conventional gas baseline, with annual electricity costs near $8 million versus approximately $12 million for full air source. The hybrid carries about $7 million more in upfront capital cost than a full air source system without federal Inflation Reduction Act incentives, which mechanical engineer Andy Olderman called outweighed by long-term performance and reliability. The committee also confirmed natural sod for relocated fields and no baseline lighting for those fields, directing the design team to price lighting and conduit as alternates for the football and cricket overlay. Exterior design discussion produced a general lean toward stacked windows and predominantly brick end walls with accent materials, but no formal confirmation; community forums on May 21 and May 24 will gather public input before a binding decision expected at an added meeting around June 2.