Plymouth County’s Mayflower Modern Challenge: Installing Heat Pumps in Historic Homes While Preserving Colonial Architecture

Bridging Centuries: How Plymouth County Homeowners Are Solving the Modern Heat Pump Challenge in Colonial Architecture

In Plymouth County, Massachusetts—home to America’s most treasured historic architecture—homeowners face a unique modern dilemma. With 146 properties listed on the National Register of Historic Places and the Plymouth Historic District comprising 286 properties representing architecture from the 17th through early 20th centuries, residents are caught between preserving their colonial heritage and embracing energy-efficient heating solutions. This challenge has become known locally as the “Mayflower Modern Challenge”—installing contemporary heat pumps while maintaining the architectural integrity that makes these homes so special.

The Historic Home Heat Pump Dilemma

The question of heat pumps in old houses is coming up a lot lately. With the great electrification upon us, heat pumps are quickly becoming the number one choice for space heating. In fact, data from the Air-Conditioning, Heating, and Refrigeration Institute showed that heat pumps outsold furnaces by 10% in 2022. However, Plymouth County’s historic homes—some dating back to the 1600s—present unique challenges that modern construction doesn’t face.

Minisplit heat pumps can be effective in heating older homes when designed and installed appropriately, but in many cases a building upgrade will be required. The building’s thermal envelope is very important, including the roof insulation, wall insulation, basement insulation and window U-value. Perhaps equally important is the air leakage rate of the building. If the building is leaky, the minisplit will struggle to make occupants comfortable.

Why Historic Homes Need Special Consideration

Colonial-era homes in Plymouth County were built with entirely different heating philosophies than today’s structures. In New England, colonists departed from traditional European construction, building wood-frame homes covered with weatherboard, clapboard, or shingles. New England seventeenth-century homes were typically two stories tall with steeply pitched roofs, essential for shedding heavy snow loads. Central chimneys were also standard, being the most efficient way to heat these buildings during cold New England winters.

These architectural features, while historically significant, create modern heating challenges. Gas boilers, which run at high flow temperatures, can heat draughty or poorly insulated homes more easily, though they are less efficient and produce higher carbon emissions. Retrofitting a heat pump, or any other heating system for that matter, in an older, poorly insulated building can pose challenges if the property’s thermal performance isn’t improved.

The Preservation vs. Efficiency Balance

Historic preservation guidelines add another layer of complexity to heat pump installations. Installing a heat pump in an old building can be more challenging. Planning controls may limit the work you can do, especially in listed buildings or conservation areas, where preserving the building’s character is important. In Plymouth County, where many homes are protected by historic district regulations, homeowners must carefully navigate these requirements.

Many historic buildings will have existing heating systems with pipework and emitters that are in good condition. It should not be assumed that these systems will need to be entirely replaced. Reusing heating systems should always be considered, as the embodied energy originally used to make the equipment can be considerable. An assessment of the existing heat emitters and pipework should be undertaken.

Success Stories from the Field

Despite the challenges, heat pumps can work effectively in historic homes with proper planning. An old house contractor in zone 5 coastal CT working on projects using heat pumps reports: “The first is from 1780 or so, the current project is 1747, but have worked on many mid 19th century homes. The 1780 house is doing just fine with no backup heat whatsoever, but it is fairly well insulated and has new double pane windows. 90% of the walls of this house are insulated with Roxul from the outside.”

There are many examples of air source heat pumps performing well in historic buildings in England. However, there are also instances where new ASHPs have not met expectations. When poorly performing systems are reported openly without exploring the underlying issues, people may conclude that heat pumps are not a suitable replacement for fossil fuel heating systems in older buildings.

Expert Installation Makes the Difference

For Plymouth County homeowners considering this transition, working with experienced local contractors is crucial. Dempsey Energy, based in North Attleboro, understands that home comfort depends on reliable HVAC systems. For over 30 years, families across Massachusetts have trusted them to keep their homes running efficiently and comfortably. Their expertise in both modern heat pump technology and the unique challenges of historic homes makes them particularly valuable for these specialized installations.

Professional Heat pump installation Plymouth County, MA requires careful attention to the building’s thermal characteristics and existing infrastructure. Above all else, the key to a successful heat pump installation lies in engaging a qualified heating engineer to design, install, and commission the system properly, ensuring it meets the specific needs of your home.

Practical Solutions for Historic Homes

Several strategies can help historic homeowners successfully integrate heat pumps:

  • Thermal envelope improvements: Many old homes feature suspended timber floors and pitched roofs, and insulating these elements can make a significant difference. Loft insulation, for instance, can be installed affordably and is particularly effective at reducing heat loss. Insulating timber floors involves more disruption but offers considerable benefits in overall comfort.
  • Radiator compatibility: Contrary to some claims, you don’t necessarily have to strip out small-bore pipework to accommodate a heat pump. In fact, heat pumps can often integrate with existing small-bore pipework, commonly using a buffer tank to help regulate the flow.
  • System sizing: Heat pumps do work in homes with poor thermal enclosures. As stated above, it’s all about delivering the right amount of BTUs. For that, you need to know how much heating load you have. A Manual J heating load calculation is one way to get there.

The Future of Historic Home Heating

As Massachusetts continues to push toward carbon neutrality, historic homeowners in Plymouth County are finding innovative ways to honor their past while embracing sustainable futures. Installing a heat pump in a new build/renovation project is going to cost far less than having to do so retrospectively in a few years. The initial costs and retrofitting challenges may seem daunting, but the adoption of renewable energy promises significant long-term benefits. Reduced running costs, lower carbon footprints, and an alignment with future trends make this transition a viable, sustainable choice.

The “Mayflower Modern Challenge” isn’t just about installing equipment—it’s about thoughtfully bridging the gap between preserving our architectural heritage and meeting contemporary energy needs. With proper planning, expert installation, and respect for historic character, Plymouth County homeowners can successfully heat their colonial treasures with modern efficiency, ensuring these irreplaceable homes remain comfortable and sustainable for generations to come.