In 2025, EnergySmart Alternatives completed a geothermal retrofit at a 2,200-square-foot home built in 1978 in Arlington. The property was originally heated with an oil boiler and cooled with a traditional central air conditioning system.

The homeowners wanted to transition away from fossil fuels and take advantage of renewable energy. By replacing the existing heating and cooling system with a high-efficiency geothermal heat pump, EnergySmart helped the homeowner significantly reduce energy costs while creating a quieter, more efficient home comfort system.

This project demonstrates that geothermal systems aren’t just for new construction; they can also be an excellent upgrade for modern homes looking to improve efficiency and sustainability.

Why This Home Was a Strong Candidate for Geothermal

Several factors made geothermal an ideal solution for this retrofit project.

The Homeowner Wanted to Eliminate Fossil Fuel Use

The homeowner was looking for a long-term solution that would reduce dependence on natural gas and move the home toward cleaner energy.

Aging Air Conditioning Equipment

The existing air conditioning system was installed in 2010. The age of the AC system made it a logical time to consider upgrading to a more efficient system that could provide both heating and cooling.

Adequate Space for Drilling

The property had sufficient space in the side yard to install the vertical boreholes needed for the geothermal loop system.

Installation Overview

To install the geothermal system, EnergySmart drilled two 6-inch diameter vertical boreholes in the side yard of the property. These boreholes serve as the underground heat exchange system that allows geothermal heat pump technology to transfer heat between the home and the earth.

High-density polyethylene (HDPE) geothermal piping was installed inside each borehole and sealed in place using geothermal grout to ensure long-term durability and efficient heat transfer.

The loop pipes were then brought into the home through two 3-inch core penetrations in the concrete foundation. Inside the mechanical space, the geothermal loops were connected to a variable-speed geothermal heat pump, which was flushed with an ethanol-based antifreeze solution to maintain safe operation during colder temperatures.

One of the advantages of this retrofit was the ability to reuse the home’s existing HVAC infrastructure. A second heating and cooling zone was added to the basement for improved comfort.

Modern heat pump thermostats were installed with WiFi connectivity, allowing the homeowner to monitor system performance and control temperatures remotely through a mobile app.

System Performance and Operating Costs

The geothermal system has delivered strong performance while dramatically improving energy efficiency.

• First Year Electricity Use (May 2025 to May 2026): approximately 3,900 kWh
• Estimated Operating Cost: about $1,200 per year at $0.30/kWh

For homeowners looking to reduce both energy bills and carbon footprint, installing a geothermal system can create a powerful high-efficiency energy solution.

Benefits of Switching from Gas to Geothermal

This retrofit provided several immediate and long-term advantages for the homeowner.

One System for Heating and Cooling

A single geothermal heat pump now provides both heating and air conditioning, eliminating the need for separate systems.

Fossil Fuel Heating Eliminated

The oil boiler is no longer needed, reducing reliance on fossil fuels and lowering emissions.

Quieter Outdoor Environment

The traditional outdoor AC condenser was removed, eliminating the noise typically associated with central air conditioning.

Improved Comfort and Efficiency

Variable-speed geothermal heat pumps provide steady temperature control, better humidity management, and improved overall comfort compared to traditional systems.

Remote Monitoring and Control

WiFi-connected thermostats allow homeowners to monitor energy usage and adjust temperatures from anywhere.

A Smart Upgrade for Homeowners Looking to Move Beyond Oil Heat

This Arlington geothermal retrofit demonstrates that homeowners don’t need to wait for a new construction project to enjoy the benefits of geothermal heating and cooling. By replacing an aging oil boiler and conventional air conditioning system with a high-efficiency geothermal heat pump, the homeowners were able to reduce their reliance on fossil fuels, improve year-round comfort, and lower their long-term operating costs.

With annual geothermal electricity usage of just 3,900 kWh and estimated heating and cooling costs of approximately $1,200 per year, this project highlights the significant efficiency gains that geothermal technology can provide. The addition of a new basement zone also improved comfort throughout the home while making better use of the existing HVAC infrastructure.

For Massachusetts homeowners facing the replacement of an oil boiler, furnace, or aging air conditioning system, geothermal can be an attractive alternative that provides heating and cooling from a single system while delivering decades of reliable performance.

EnergySmart Alternatives specializes in geothermal retrofits for existing homes throughout Massachusetts. If you’re considering replacing an older heating or cooling system, our team can evaluate your property and help determine whether geothermal is the right solution for your home.

In 2017–2018, EnergySmart Alternatives installed a geothermal heat pump system at Louisa May Alcott’s Orchard House in Concord, Massachusetts, the beloved home where Louisa May Alcott wrote Little Women. Originally built in the 1660s and listed on the National Register of Historic Places, the property presented unique mechanical and preservation challenges.

With no insulation and original single-pane windows, the building required a heating and cooling solution that would improve comfort without compromising its historic integrity.

This project demonstrates how geothermal technology can successfully modernize even the most sensitive and historically significant structures.

Why Geothermal Was the Right Choice for a Historic Landmark

Historic buildings demand thoughtful system design. In this case, geothermal offered several distinct advantages:

1. End-of-Life Heating System

The existing fossil fuel system had reached the end of its service life. Replacement was necessary, creating an opportunity to upgrade to a cleaner, more efficient solution.

2. Poor Performance & Complicated Controls

The previous heating and cooling system was overly complex, difficult to service, and failed to maintain consistent comfort levels for visitors and staff.

3. No Outdoor Equipment Allowed

Because of the building’s historic designation, outdoor condensers and visible mechanical equipment were prohibited. Unlike conventional HVAC systems, geothermal operates without outdoor units—making it ideal for preservation-restricted properties.

4. Quiet Operation for a Museum Environment

As a public museum welcoming thousands of visitors annually, quiet performance was critical. Geothermal systems operate with minimal sound, enhancing the visitor experience.

5. Available Space for Drilling

The property allowed for vertical borehole installation without disturbing the historical structure itself.

Installation Overview

The project included eight 6-inch diameter vertical boreholes, spaced approximately 15 feet apart. Each borehole was fitted with geothermal piping and sealed with thermal grout to ensure optimal long-term heat transfer.

The geothermal loop lines were routed into the basement through a newer section of concrete foundation, approximately four feet below grade, preserving the original historic structure.

Inside the building, the system was connected to four geothermal heat pumps strategically located throughout the property. The loop system was flushed with an ethanol-based antifreeze solution to ensure reliable year-round operation.

A new forced air duct system was installed to improve airflow and temperature consistency throughout the museum spaces.

To maintain the building’s historic appearance:

• Discreet room sensors were installed instead of modern touchscreen thermostats in exhibit areas.
• Real-time energy monitoring was integrated for remote management via app.
• System controls were simplified for easier operation by staff.

Measurable Results & Operational Impact

The performance improvements have been substantial.

• 40–50% Annual Operating Cost Savings
  The geothermal system significantly reduced energy costs while maintaining more stable indoor temperatures.
• Gas Service Eliminated
  The gas meter was completely removed, eliminating fossil fuel dependency and combustion risks inside a centuries-old wooden structure. Learn more about the sustainable innovations.
• 2025 Electricity Usage: Approximately 23,000 kWh
  At $0.30 per kWh, annual operating cost was approximately $6,900.

For a large, uninsulated 17th-century structure open to the public, these results represent an impressive balance between preservation and modern efficiency.

Why Geothermal Is Ideal for Historic and Institutional Buildings

This project highlights key advantages of geothermal systems in historic, museum, and landmark properties:

No Outdoor Condensers or Vents

Preserves exterior aesthetics and meets strict historic preservation requirements.

Elimination of Combustion

Removing gas-fired equipment reduces fire risk and protects irreplaceable historic materials.

One System for Heating & Cooling

A single geothermal system replaces multiple mechanical components, simplifying operation and maintenance.

Quiet Performance

Creates a more enjoyable experience for visitors in museums, libraries, and cultural spaces.

Improved Comfort & Humidity Control

Variable-speed operation provides better temperature stability and humidity management, critical for protecting antique furnishings and artifacts.

Remote Monitoring & Control

WiFi-connected monitoring allows building managers to oversee system performance and respond quickly to any issues.

A Model for Modernizing Historic Properties

The successful geothermal retrofit at Louisa May Alcott’s Orchard House demonstrates that even centuries-old, nationally recognized historic buildings can benefit from advanced, high-efficiency mechanical systems, without compromising architectural integrity.

For historic homeowners, museums, religious institutions, and preservation organizations throughout Massachusetts, geothermal heating and cooling offers:

• Long-term cost stability
• Reduced environmental impact
• Enhanced preservation protection
• Quiet, discreet performance
• Elimination of fossil fuel dependency

EnergySmart Alternatives specializes in designing geothermal systems for both new construction and complex retrofit applications, including some of New England’s most notable historic properties.

If your property requires an HVAC upgrade but must meet preservation standards, geothermal may be the solution that balances modern performance with historic responsibility. Contact us today to get started.