Eagleville Green by Mansfield Nonprofit Housing Development Corporation

Eagleville Green consists of seven newly constructed buildings with 41 affordable dwelling units. PHIUS Zero certification is pending. While design decisions focused on program requirements, the team also prioritized low emitting, durable products with low embodied carbon. Rigorous oversight included: plan and specification reviews, multiple modeling iterations, on-site verification, on-site preliminary testing for window infiltration, building air infiltration, and assembly connections. These all-electric buildings include Fujitsu non-ducted Heat Pumps, Zehnder ComfoAir350 ERV's, and Sanden Eco2 Heat Pump Water Heaters. While the individual entrances evoke a community feel, each home has its own front and back porch, they pose a challenge for whole building air infiltration testing. To meet this PHIUS+ requirement, the project team cut openings from one unit to the next and disconnected the in-unit ERV’s. Once the whole building tests are complete, the team patched the openings and Steven Winter Associates (SWA) raters completed the compartmentalization testing of each unit. ERV’s were then reconnected, balanced, and ventilation was final tested.

To ensure a comfortable, efficient envelope, the building is wrapped in Henry Blueskin with R21 Johns Mansfield ThermaBoard continuous insulation (ci) and R20 blown cellulose in cavities. Supply chain issues meant pivoting from the originally specified Rockwool ci but the team resisted plastic based products to align with their low embodied carbon goals and waited for the ThermaBoard product to become available. R80 blown cellulose in attics lays on top of the Intello Plus air barrier that’s taped and foamed at seams and penetrations. Due to their small footprint, the buildings required extensive foundation insulation including R10 on the footings interior and exterior walls and R24 – R40 under the slab and at haunches.

SWA utilized the BEAM tool to inform product choices and to predict embodied carbon emissions. Building three with six-units and eight-bedrooms produces 93,806 kg CO2e or 178 kg CO2e/m2. This is about 15% less than the average reported by RMI for a new home (184 kg CO2e/m2) . Also contributing to the team’s goals to reduce embodied carbon, the existing building on the Eagleville Green site was completely renovated, rather than demolished, to house another apartment over an office and maintenance area.  

Eagleville Green provides quiet, comfortable, resilient, and beautiful homes for an area in much-need of affordable housing. The project team, Dorgan Architecture and Planning, Schadler Selnau Associates, PC, and Enterprise Builders, is proud to have prioritized sustainability, electrification, and decarbonization during the design, construction, and occupancy phases of this project.