A Rebuild That Redefined What Their Home Could Be
Cynthia and Tim set out to transform their Somerville property into a more energy-efficient, comfortable, and sustainable home. Originally considering a deep energy retrofit, they ultimately decided to rebuild from the ground up using Bensonwood’s prefabricated, panelized construction, resulting in a high-performance, all-electric home that met Mass Save’s Tier Two standards and earned a $25,000 incentive.
Why a Deep Retrofit Wasn’t Enough
Located on an urban lot close to the metro, the couple’s mid-century home offered convenience but lacked comfort and energy efficiency. Tim and Cynthia wanted to modernize their living space while reducing carbon emissions, energy costs, and maintenance needs.
After exploring traditional renovation options, they realized that even a deep retrofit wouldn’t achieve their goals for performance or longevity. Instead, they chose to build a new, prefabricated home using a high-performance wall panel system, precision-built in a factory, then assembled onsite and finished by a local builder.
Balancing High Performance with Urban Constraints
The challenge was to create a durable, all-electric home that maximized energy performance and comfort, all within a dense urban setting where construction disruptions could easily affect neighbors. The homeowners sought a fast, efficient building process that would minimize noise and traffic while delivering exceptional performance results.
Precision Fabrication that Minimized Disruption
The team selected a prefabricated, panelized building system, allowing most of the heavy construction to occur offsite. Once delivered, the home was assembled in just four days, drastically reducing neighborhood disruption.
The design incorporated:
- High R-value insulation (R-35 walls, R-58 roof).
- Triple-paned European tilt-turn windows for superior soundproofing and thermal performance.
- All-electric systems, including air-source heat pumps and an induction range.
- Heat recovery ventilation (HRV) for continuous fresh air circulation and improved indoor air quality.
- Heat pump water heater for efficient, low-cost hot water.
A Quiet, Efficient, All-Electric Home Built for the City
The completed residence is a model of urban high-performance design — quiet, efficient, and comfortable year-round.
- Fast Construction: Home assembled onsite in only four days, minimizing disruption.
- Energy Efficiency: Qualified for Mass Save Tier Two, earning a $25,000 incentive.
- Comfort: Exceptional thermal comfort and quiet interiors, even in the city.
- Healthy Living: Continuous fresh air and filtration with an HRV system.
- All-Electric Performance: Efficient systems for heating, cooling, cooking, and hot water.
- Design Appeal: A timeless, modern design that fits seamlessly into a 75–100-year-old neighborhood.
- Sustainability: A model for future urban infill projects that prioritize performance, resilience, and community appeal.
The High-Performance Details Behind the Design
- Certifications
- U.S. Environmental Protection Agency (EPA) XXYZ.
- EPA Indoor airPLUS.
- U.S. Department of Energy Zero Energy Ready Home.
- EPA WaterSense.
- Building Envelope
- Infiltration: Blower door test achieved at impressive .63 ACH50.
- Attic: Air Sealed and insulated with loose-fill cellulose (R-56).
- Walls: 9.5” prefabricated exterior walls wooden I-Beams with OSB on both exterior and interior layers plus dense-packed cellulose (R-35).
- Windows: Triple-paned, double-gasketed with .16 U-factor and .38 Solar Heat Gain Coefficient (SHGC).
- Foundation: Standard poured concrete walls: Rigid foam board (R-15).
- HVAC
- Mitsubishi non-ducted 11.0 Heating Seasonal Performance Factor (HSPF) and 18 Seasonal Energy Efficiency Rating (SEER) air-to-air heat pump provides heating and cooling for bedrooms and bathrooms.
- Airia Brands Lifebreath HRV system (72 CFM/35 watts) supplies fresh, balanced, filtered air to the living space 24 hours per day.
- Hot Water
- Bradford White 50-Gallon heat pump hot water heater (3.44 UEF).
- Solar and EV Charging
- 7.2 kW solar array was installed on the roof to satisfy all of the home’s electric needs. The system frequently generates twice its current load, so it is better than Net Zero.
- Electric vehicle charging station ready – the owners currently have electric bikes instead.
- Annual Electric savings: $5,694.
A Home (and Homeowner) that Gives Back More than it Consumes
This home showcases how prefabricated, all-electric construction can deliver exceptional performance and sustainability, even on compact urban lots. Thanks to its outstanding energy efficiency, the solar array has produced far more electricity than the homeowners consume, earning them a surplus credit with Eversource in just over a year.
Even better, Cynthia and Tim chose to share their success by donating their excess energy credits to the Somerville Homeless Coalition, helping offset electricity costs for those in need. Through Eversource’s program, surplus credits can be banked or transferred to another account—an opportunity these generous homeowners were proud to embrace.
Development Team:
- Architect/Designer and Offsite Fabricator: Bensonwood
- Contractor: McHugh Custom Builders
- Solar: East Coast Solar
- HERS Rater: A9 Green Total Green Energy Solution
- Photographer: John Hession
Discover More Of Tim and Cynthia’s Journey Here:
