How energy efficiency programs can support affordable multifamily redevelopment: lessons from a Boston project

Boston, MA Across New England, owners and developers working with older multifamily properties face a common challenge: how to modernize aging building systems while managing project costs and preserving affordability. Energy efficiency programs can help make those investments more achievable. Eversource offers programs in Massachusetts, Connecticut and New Hampshire that connect eligible projects with technical guidance, rebates and incentives for energy-efficient improvements.

The redevelopment of 43 Hemenway St. in Boston illustrates what that support made possible. With support from the Mass Save Multi-family program sponsored by Eversource, Fenway Forward, a Boston-based, non-profit community development organization, transformed the six-unit property into affordable condominiums with modern, all-electric heating and cooling. The result shows that even older multifamily properties can be strong candidates for electrification when energy efficiency and available program support are considered early in redevelopment planning.

A Strategic Shift to Electrification and Energy Efficiency
The project centered on a full replacement of the building’s outdated oil heating system with high‑efficiency air-source heat pumps in each of the six units, which range in size from studios to three-bedrooms. The new systems deliver heating, cooling, and dehumidification while eliminating on‑site fossil fuel use.

Through the Mass Save Multi‑family program, incentives covered the entire cost of the heat pump installation – an investment that allowed Fenway Forward to redirect resources toward additional building improvements. This comprehensive support ensured that the project could meet both affordability and sustainability goals without placing additional financial burden on future homeowners.

The shift from oil to high‑efficiency electric systems delivers measurable benefits:

• Annual oil savings: 1,300 therms; and

• CO2 reduction: 195 tons.

Equivalent to avoiding more than 450,000 miles driven in a gas‑powered car

In parallel with the electrification work, additional renovation measures – such as the installation of triple-pane windows, new roof and envelope improvements, and targeted insulation – were made possible by separate investments from the city of Boston Mayor’s Office of Housing, The Life Initiative, Samuels & Associates, Charlesbank Homes Foundation, Eastern Bank Foundation and Beth Israel Lahey Health, strengthening overall building performance and resident experience.

These measures reduce heat loss, improve indoor temperature stability, and support the performance of the newly installed heat pumps. Together, they create a more resilient building that is better equipped to manage seasonal temperature swings and long-term energy demands.

With the upgrades complete, condo owners now experience:

• Consistent indoor temperatures across seasons;

• Efficient cooling and dehumidification;

• Quiet system operation;

• Elimination of oil deliveries and associated maintenance; and

• A fully electric building aligned with modern sustainability standards

Altogether, these enhancements will strengthen long-term affordability by reducing energy use and operating costs, while improving comfort for residents year‑round.

A Collaborative Approach to Modernizing Affordable Housing
The redevelopment of 43 Hemenway St. reflects the value of coordinated partnerships in advancing energy‑efficient affordable housing. Fenway Forward worked with Eversource to leverage available incentives for the heat pump installation, while municipal and private partners supported other elements of the redevelopment. Together, these resources allowed the project team to address both mechanical systems and building-envelope needs while ensuring a comfortable space for residents for years to come. This model demonstrates how small multi‑family buildings – particularly historic properties – can successfully transition to high-efficiency, all‑electric systems without compromising affordability or resident experience. It also highlights how utility‑sponsored programs can accelerate electrification in older housing stock, which can often face structural and financial barriers to modernization across New England.

Lessons for Multifamily Redevelopment Across New England
As property owners and developers across New England look to expand affordable housing, manage project costs and meet aggressive climate targets, 43 Hemenway St. offers a replicable blueprint for what energy-efficient redevelopment can achieve, even in an older multifamily building. 

The project demonstrates that:

• Electrification can be cost-effective when paired with available incentives;

• Building envelope improvements amplify the performance of high-efficiency systems;

• Strategic partnerships can unlock funding and streamline redevelopment; and

• Small multi‑family buildings can achieve meaningful carbon reductions without sacrificing affordability.

For developers, municipalities, and community organizations, the lessons from 43 Hemenway St. underscore the importance of integrating energy‑efficient design into redevelopment planning from the outset. Eversource can help eligible property owners identify and access state-specific programs, technical guidance and practical opportunities to pursue energy-efficiency improvements. With the right combination of incentives, collaboration, and technical strategy, affordable housing can be both sustainable and financially accessible.

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