November 11, 2019. Central to the development of Hook & Ladder Apartments (2318 Jefferson St. NE) – a brand-new multi-family affordable housing project – was incorporating practices that go beyond everyday notions of sustainability. That challenge to the architects and contractors has netted a green model worthy of industry study that also promises a truly unique living experience to its residents.
The 118-unit development consists of two buildings of one-, two-, and three-bedroom apartment homes. One was built using Enterprise Green Community strategies, while the other is certified to meet the Passive House Institute US (PHIUS) standard.
Excellent Indoor Air Quality
LHB’s Kim Bretheim, the lead architect for Hook & Ladder, explained that the Green Community building was a “relatively enhanced performing building from a sustainable perspective,” with eco-friendly practices applied to its energy use, indoor air quality, and stormwater management. The passive house building incorporated those same techniques but went even further in its treatment of energy and air quality. Additional energy-efficiency was achieved “by making the building very airtight and enhancing the thermal envelope,” noted Bretheim.
Utilization of passive house technology, including material selection, has a dramatic, discernible effect on both energy usage and resident ambient comfort. The impact on energy is so substantial that the passive building is projected to use less energy to heat and cool rooms than it will to heat domestic hot water.
Precipitate Architecture founder Elizabeth Turner, an architect and Certified Passive House Consultant (CHPC), provided expertise for that building.
The variable refrigerant flow (VRF) system used in the passive house structure “shares energy across the entire building, reducing the need to even turn on the heating or cooling during temperate days in the fall and spring,” said Turner.
Superior air quality is achieved through a whole-building energy recovery ventilation system that provides a consistent supply of fresh air, without drafts, in a carefully controlled, airtight structure. Plus, the triple-glazed windows give the building incredibly quiet interiors. “You get a much better sound attenuation between outside and inside spaces,” explained Bretheim.
Energy Performance Studied
The overarching goal for Hook & Ladder was not just sustainability but a more beautiful, comfortable, and high-quality living environment than what affordable housing typically provides. To that end, the project also includes a maker space; a fitness center; a community room; a bike storage area; a dog run; a playground; and a butterfly-friendly landscape featuring native plants and rain gardens.
The core challenge, though, was designing and constructing a building that would meet Passive House Certification requirements. After all, Hook & Ladder is the first multi-family passive house ever built in the Twin Cities’ climate zone. “We set out not knowing if we could do it,” said Turner, “and we did. So, that was pretty exciting!”
Hook & Ladder’s side-by-side passive house and green building are so noteworthy, they will be studied by the industry. The Center for Sustainable Building Research (CSBR) at the University of Minnesota will be observing metrics, and Xcel Energy will provide research funds. “There are a lot of people who want to see how it’s performing,” said Bretheim.
Beautiful and Comfortable
The project had to be innovative while still embracing the construction practices familiar to traditional contractors. Plumbers and electricians unfamiliar with passive house technology drill holes through studs and materials to integrate their systems into buildings, something antithetical to usual passive house standards and the quest for an airtight structure.
To accommodate that practice, the team developed a two-part exterior wall. One part “was airtight and could not be penetrated,” noted Bretheim, while the other part “allowed the electricians and plumbers to drill holes in accordance with their standard construction practices.”
Through a collaborative dynamic, the Hook & Ladder design and construction pros were able to do something that had never been done before. “Minnesota has always had a really good culture of supporting sustainable design work,” said Turner, “but this is next-level building science.” In the process, the team created a beautiful and comfortable atmosphere that more than 100 families will be thrilled to call home.
About the author
Kent Roberts is a freelance writer who lives in Minneapolis and who deeply values sustainability. Along with many business articles, he has also written headlines for The Onion and is at work on a humorous book on the cultural impact of neurodiversity, called And Stuff.