This edition of the Phius Project Spotlight Series highlights the J.J. Carroll House senior living facility in Boston, Massachusetts.
Our monthly Project Spotlights highlight the cutting-edge work being done by Phius professionals and provide examples of successful design and construction strategies. We feature projects of various sizes, typologies and climate zones, offering you a peek behind the curtain of each.
Our November Project Spotlight is: J.J. Carroll House in Boston, Massachusetts! The project was recently recognized as the winner in the High-Rise Multifamily and Best Project by a Young Professional categories in the 2025 Phius Passive Projects Design Competition.
J.J. Carroll House was designed and built with energy efficiency, emissions reduction, and long-term climate resilience at its core.
The building’s high-performance envelope plays a central role in limiting its energy use. J.J. Carroll House includes 2.5" of continuous exterior insulation paired with dense-pack cellulose cavity insulation. To minimize thermal bridging, fiberglass Z-girts were used at attachment points. The envelope features R-31 wood-framed walls and an R-40 roof, supported by airtight construction with a verified final infiltration rate of just 0.057 cfm50/sf of enclosure. Triple-pane, argon-filled IGUs (U-0.10 to 0.11) were used throughout fixed, casement, and storefront windows, with whole window U-values as low as 0.14. Advanced, thermally broken storefront framing systems were installed at the ground level.
Mechanical systems are optimized for energy efficiency and occupant health. Heating and cooling are delivered via a high-efficiency VRF air-source heat pump system with heat recovery. Ventilation in all interior spaces is provided by energy recovery ventilators (ERVs), including seven semi-centralized rooftop ERVs and six additional individual units serving common areas. The rooftop ERVs include high-performance enthalpy wheels with total recovery effectiveness up to 81.4%, significantly reducing heating and cooling demand.
Material selection reduced both operational and embodied carbon. Five of the six stories were built using wood framing, reducing embodied emissions, which was further supported by the use of environmentally responsible insulation materials, including mineral wool and dense-pack cellulose.
To offset grid electricity consumption, the project incorporates a substantial on-site renewable energy system. A 156 kWDC rooftop PV array spans all five towers and is estimated to produce 197,852 kWh annually. This system supports the project’s goal of reducing operational emissions, enhancing energy resilience, and limiting
2Life Communities’ J.J. Carroll House, located in the Brighton neighborhood of Boston, addresses the region’s growing senior housing crisis and serves as a model of affordable, energy efficient and service-enriched living. The development integrates healthcare and housing, promotes community-based senior living, and exceeds sustainability standards, all while providing housing that addresses the two biggest threats to optimal aging: loneliness and economic insecurity.
J.J. Carroll House consists of 142 apartments for seniors ages 62+. All are affordable to households up to 60% AMI and have universal design and adaptability features aimed to keep residents living independently as physical needs change. A lively ground-floor Village Center includes accessible and flexible common spaces such as a multipurpose room, resale shop, and salon.
The new building also includes an 11,000 sf PACE center operated by Element Care. PACE is a comprehensive health and wellness program that helps frail extremely low-income seniors meet their health care needs in the community instead of going to a nursing home. An enclosed pedestrian bridge creates a year-round accessible connection directly to the rest of 2Life’s Brighton campus, which includes a library, fitness center, computer center, art room, state-of-the-art auditorium, and a wide variety of programs and services.
J.J. Carroll House exemplifies high-performance design through its commitment to energy efficiency and sustainability. It sets a new benchmark for affordable senior housing by exceeding building code requirements and dramatically reducing energy consumption. J.J. Carroll House received Phius+ 2018 CORE Certification on April 28, 2025. It is the largest Phius Certified building in Massachusetts and among the top 10 in North America as of its Certification.
The building’s form and performance were shaped by core passive building principles, including an airtight envelope, continuous insulation, and high-performance windows and doors. These strategies minimize heat loss during winter and heat gain during summer, maintaining comfortable indoor temperatures year-round while reducing reliance on mechanical systems. Strategic window placement maximizes natural light, lowering energy demand for artificial lighting and enhancing residents’ comfort and wellbeing. Operable windows allow for user control, empowering residents to naturally ventilate their spaces during mild weather.
Images by MASS Design, Resonant Energy, 2Life Communities