154 Broadway sets an example for high performance, low-carbon mixed-use development in East Somerville. A five-story building with commercial space on the ground floor and 45 rental dwelling units on the upper floors, the project has achieved Passive House design certification through the Phius 2021 Core standard and utilizes mass timber construction for the majority of its floor systems. The project will increase Somerville’s housing stock and help to relieve some of the pressure on existing larger family-size units by providing many full service, well-appointed studio units. The project includes 40 studios, 3 one-bedroom units, and 2 three-bedroom units, of which 9 are affordable. Through its all-electric Passive House design, the building meets the City of Somerville’s zoning definition of a Net Zero Ready Building.

The façade design is inspired by the vibrant textures, colors, and scale of materials observed throughout the neighborhood and along Broadway. The ground floor features active retail frontage and residential lobby space, both with storefront windows to visually connect ground floor uses and the public realm. The height of the ground floor aligns with a key datum on the building just to the north for street front continuity. Where facing Broadway, the upper floors are clad in a mosaic of rainscreen siding, which reduces the massing via relief, shadow, and color variation. The depth of windows provides both shading and play of light throughout the day. The massing’s stepback at the fifth floor creates space for private tenant terraces and its roofline is a contemporary echo of the pitched roofs from the neighborhood. In the rear of the site the fourth floor amenity room opens out to a generous landscaped communal terrace that grants tenants and guests a panorama of the Boston skyline to the south.'

As an all-electric project, 154 Broadway will have zero on-site fossil fuel combustion and, through its Passive House design, greatly lowers demand on the electricity grid through an efficient, airtight envelope, high-performance energy recovery ventilation, and cold-climate heat pumps.

The project site provides easy access to transit and bicycle networks, and it is located close to neighborhood amenities such as green space, restaurants, a grocery store, and a branch of the Somerville public library. The project enhances the pedestrian experience along Broadway by eliminating two existing curb cuts and in their place rebuilding an uninterrupted sidewalk and planting new street trees. No off-street car parking is provided; instead ample bicycle parking on the ground floor encourages alternative modes of transportation.

Setbacks at the rear of the building create south-facing semi-public outdoor amenity terraces and vegetated areas, while solar control is provided via horizontal overhangs above windows. A 28 kW solar array helps to offset common area electrical loads.

The project achieved Phius Core 2021 Design Certification in August 2022. The WUFI Passive modeling tool metrics graph below shows the design’s exceptional performance in driving down annual energy demand and peak loads with respect to Passive House targets.