733 Broadway is a historic warehouse building in Lowell, Massachusetts, that underwent extensive renovations to meet the rigorous standards of Passive House design.

The project includes 52 affordable residential units, generous amenity spaces, and a street-level parking garage.

As a registered historic building, the project required careful coordination between Linnean and the design team to enhance the thermal envelope while preserving the building's historic character. This included restoring the original exterior masonry walls and replicating the original windows with high-performance replacements.

The project achieved final certification under the Phius 2024 CORE standard in April 2026.