Implementing angled geothermal drilling
An innovative borefield design used angled drilling beneath the existing building, overcoming space constraints and enabling geothermal installation without disrupting the historic structure.
Practices
Priorities
Retrofitting with geothermal in a constrained setting
By 2023, Christ Church’s aging heating system was failing, and the 125‑year‑old building lacked air conditioning. Limited drilling space and sensitive historic features made conventional upgrades impractical. Seeking a long‑term, efficient solution to keep its doors open, the church selected geothermal for heating and cooling. CDM Smith tailored engineering design services to the historically significant site, which necessitated angled drilling in a residential neighborhood.
Protecting historic and sensitive features
Careful coordination safeguarded critical elements, including the church’s historic organ, while construction activities progressed within a fully occupied community space.
Managing complex site logistics
The project incorporated detailed logistics planning, construction fencing, sediment controls, stormwater routing and accessible pedestrian pathways to support safe, orderly construction.
Delivering long-term energy performance
The geothermal system provides efficient heating and cooling, reducing operating costs and carbon emissions while ensuring reliable comfort for worship services and community events.
Through close collaboration with ZBF Geothermal, LLC and Rototec, the project team delivered a geothermal system once considered impractical for historic retrofits. The use of angled boreholes and coordinated construction allowed Christ Church to modernize its energy infrastructure while protecting its architectural legacy. The system is expected to lower long‑term energy costs, reduce environmental impact and provide dependable comfort for the Bronxville community. As of 2026, the project is complete, positioning the church to serve as a community gathering space for generations to come.
Chris Church Bronxville: Geothermal Innovation
