Update: September 8, 2025:
The geothermal HVAC project is moving swiftly toward its expected completion in mid-October. The well field—18 wells, each 850 feet deep—is finished and piped into what was once the boiler room, soon to become the new geothermal heat pump room.
Inside the church and on the roof, activity is buzzing. The seven old rooftop units have been removed and replaced with two modern air-handling units. On the second floor, classroom ceilings have been opened to run new piping from the rooftop units down to the sub-basement. Meanwhile, the former boiler room is being fully transformed into the geothermal hub, and the electrical switchgear is being upgraded with new panels to power the system.
The video below offers a short walk-through of the project, giving you a glimpse of the progress and the intensity of the work underway.
Update: July 31, 2025:
Geothermal well drilling is complete! All 18 geothermal wells have been drilled. Each well is 850 feet deep and are located in our driveway that goes around the church and a few in the cloister garden area. The next step is to dig the trenches and lay in piping that connects the wells. This will take approximately 2 weeks. This will include boring holes to bring the piping into the former boiler room from the cloister and from the graveyard sides of the church. After that work will begin on the rooftop to remove the old roof top units and prepare for the new ones. If you did not see the drilling, you can find videos about it below.
Check out these two short drone video clips of the work in progress the week of July 14-18, 2025:
Geothermal HVAC Project Update – 7.2.25:
If you have passed by the church building in Wellesley lately you will have seen the drill rig and supporting equipment working in the driveway. The drilling of the remaining 17 wells is well underway. 6 of the 850 foot deep wells are complete, so including the well drilled in December, 7 of the 18 wells are drilled. The drill crew is averaging two days for each well including setup time that used to reposition the drill rig and its supporting tailings tank (catches the lubricating water and ground rock from the drilling). The recent hot weather did not slow down the drill team!
This link shows a diagram of how the 18 wells are located all around the church building. The location of the wells are carefully calculated to provide sufficient distance between the wells such that the heat energy they pull out of the ground (in the heating mode) or put back into the ground (in the air conditioning mode) does not affect the adjacent wells.
While the building is shut down, our own team led by our facilities manager Emilio DelVecchio, is working on maintenance projects that are most efficiently accomplished when the building is shutdown such as painting and floor tile repair.
| Geothermal project
In 2014, the Village Church congregation charged the Energy Committee to guide us to “be better stewards of God’s creation through increased energy efficiency and renewable energy with the goal of achieving net-zero energy usage.” Since then, we have made a number of steps toward decarbonizing our church building and operations, including installing solar panels on the roof, and steps to reduce our overall energy consumption
This year the Village Church has launched the Empowering the Future campaign to replace its aging heating and ventilation system with 100% clean, renewable geothermal energy.
Partnering with local firms GreenerU, Skillings & Sons, Elevated Design, Inc., Favulli Electric, J.S. Mortimer, and Edge Automation, Village Church in Wellesley has begun the process of drilling 18 geothermal wells that will supply heating and cooling throughout the building, replacing an oil-based heating system.
Village Church in Wellesley: fast facts
- 18 geothermal wells will be drilled up to 850 feet down through the church’s parking lot.
- The geothermal system replaces an oil-based heating system and inefficient electric air conditioning system.
- The church will replace seven rooftop heating units with just two.
- Geothermal will reduce the church’s overall greenhouse gas emissions by 75%. When the electrical power supplied by the Town of Wellesley reaches net-zero emissions, the geothermal system will be net zero.
Q&A
- What is geothermal energy?
- Geothermal energy, also known as ground-source heat pumps, works by extracting heat from the earth’s crust that can be used to heat spaces and water in a building. Heat pumps transfer this heat into buildings using a closed-loop system and a refrigerant that can heat or cool a space as needed.
- Why did Village Church opt for a geothermal system?
- The congregation of Village Church charged the Energy Committee to achieve a goal of net-zero energy usage. Heat pump systems can eliminate the use of fossil fuels that are often burned on site to supply heat for buildings and hot-water supplies. Geothermal systems rely on electric-powered pumps, which can then be supplied with clean and renewable electricity, to move heating and cooling through spaces.
- While first costs of geothermal energy are typically higher than they are for air-source heat pumps and natural gas, geothermal wells can last up to 100 years and cost less in operations and maintenance. Federal investment tax credits under the 2022 Inflation Reduction Act that non-profit organizations can now utilize helped to bring the costs of geothermal to parity with air-source heat pumps and natural gas solutions.
- In December 2024, Village Church’s congregation overwhelmingly voted in favor of ground-source heat pumps. Drilling began later that month and construction to replace the church’s heating units will be ongoing until fall 2025.
- What were the alternatives to installing geothermal?
- The church could have simply replaced its oil-based heating system with one in kind, but that would not have helped us achieve our net-zero energy goal. We also explored air-source heat pumps. A lifecycle cost analysis determined that the total cost of ownership would have been more expensive, as air-source heat pumps have an approximate 20-year lifespan before needing to be replaced.
- How does geothermal help the environment?
- Geothermal is a 100% clean, renewable heating source that takes advantage of the difference between a constant temperature below the earth’s surface and varying temperatures above it. By removing oil- or gas-fired heating equipment, the church is no longer producing greenhouse gas emissions from those sources. Emissions from greenhouse gas emissions are the leading cause of global climate change and extreme weather events.
Video documentation of the first well drilling at the Wellesley Congregational Church (Village Church in Wellesley) December 26 – 31, 2024.
Over the summer Village Church in Wellesley will drill the remaining 17 wells and complete the work of replacing its aging HVAC system with an environmentally sustainable geothermal system. View a brief video below to learn more.
Due to this project our 9am Sunday summer worship services will be held in our Weston campus, June 8-Aug. 31.
Thank you to Board of Properties co-chair, Mark Lenci for this video presentation.
Watch this brief video to learn about our geothermal system project: