Old Colony Phase 6

Passive house with annexair

The City of Boston sought to complete a 10-year redevelopment of the Old Colony site in South Boston with its final phase: a five-story building featuring 89 new income-restricted apartments ranging from one to five bedrooms. Phase 6 also includes age-restricted senior housing and a ground-floor space leased to a local arts organization that serves low-income residents. To ensure long-term sustainability, the project targeted Passive House certification.

Petersen Engineering was selected for the MEP design due to their expertise in high-performance buildings and Passive House projects. Petersen chose Annexair ERV units because of Annexair’s specialization in sustainable equipment capable of meeting rigorous Passive House standards—including their newest bio-composite casing made from recycled plastic beverage containers.

HVAC Highlights

• Oversized components to meet Passive House Watt/CFM requirements
• Low-noise design (perforated panels, acoustical louvers)
• Enthalpy wheels, dual DX coils, EC fans
• Bio-composite casing

The Annexair units for Old Colony Phase 6 were designed using the Bio-Composite panel system to meet strict Passive House energy requirements. All major components—enthalpy wheels, DX and electric coils, filter banks, and fans—were oversized to reduce air-pressure drop, lowering required fan horsepower and achieving an overall energy use of less than 1 watt per CFM of airflow.

The bio-composite construction provides a lifetime anti-corrosion warranty, 2″ R-14 (or 3″ R-21) insulation, zero thermal bridging, and a unibody structure formed from six seamless panels “welded” together to minimize leakage. A 1/8″ self-leveling floor sealer ensures a 100% leak-proof base—all delivered at the same cost as traditional unit construction.