Passive House Design Case Studies

Multi-family residents are more concerned than ever with the health and comfort of their indoor environment.

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This concern, heightened by COVID-19, has resulted in an increasing number of apartment projects to be designed and built to passive house standards promulgated by the Passive House Institute US, a nonprofit organization committed to making high performance passive construction the current market standard.

“Tenants are looking for these buildings now because they want to live in buildings that have good indoor air quality and are willing to pay more money,” said Katrin Klingenberg, executive director of PHIUS. “For a for-profit developer, if people are willing to pay even $50 more per month, that translates into direct value for your building.”

According to PHIUS, passive buildings are designed and built according to the following five principles: continuous insulation over the entire envelope without any thermal bridge, an airtight building envelope that prevents outside air infiltration and heat loss air conditioning, efficient windows, balanced ventilation with heat and humidity recovery and the use of a minimal space conditioning system.

Multi-family developers seeking PHIUS certification should expect a cost premium of approximately 0-3% over the standard Energy Star building baseline. But the additional cost is recovered by significant energy savings. According to PHIUS, PHIUS buildings are 60-85% more energy efficient than traditional buildings, making passive house a viable option for affordable properties as well as luxury.

Since 2011, 73 multi-family projects have obtained PHIUS certification.

The playful roofline of the project denotes a bird in flight. The design reminiscent of a bird’s wings not only provides shade but inspired the team to rename the project “Finch”. Image courtesy of Robert Umenhofer

Affordability meets living comfort

Finch Cambridge, Cambridge, Mass.

Finch Cambridge, a 98-unit mixed-income affordable housing development in Cambridge, Massachusetts, offers one- to three-bedroom apartments for very low-income households (less than 30% of area median income), low and middle income. households (30 to 80% of AMIs) and middle-income households (80 to 100% of AMIs). According to the developer, Homeowners Rehab Inc., it is the largest new construction of 100% affordable housing built in Cambridge in 40 years and the largest multi-family passive house development in Massachusetts.

A community engagement coordinator will be on hand to lead programs for all residents, including healthy cooking classes, as well as a farmer’s market and gardening program. Image courtesy of Robert Umenhofer

HRI, which has completed net zero projects and three LEED Platinum-certified new developments, likes to incorporate sustainability into its developments “to provide healthy homes for our tenants,” said Jane Carbone, HRI’s Director of Development.

The project incorporates elements of “active design” to encourage health and well-being and includes all-electric HVAC systems designed for comfortable living and low electricity bills, while the whole ventilation system of the building improves health and reduces allergens, with continuously filtered fresh air supplied to each unit.

High performance triple glazed windows provide daylight and fresh air, while exterior shading prevents solar heat gain during the summer months. The result: a 70% reduction in energy consumption compared to the national average for multi-family dwellings. Devices monitor air quality, energy consumption, water consumption and carbon emissions to continuously monitor building performance.

Finch Cambridge was designed to mirror the forested areas of the adjacent Fresh Pond Reserve through a treehouse design. Residents are encouraged to use the open stairwell and take advantage of the nearby walking paths. Facilities include a large multi-purpose community hall and kitchen, residents’ lounge, study rooms, roof terrace and landscaped outdoor areas.

HRI worked with NEI General Contracting and ICON Architecture on the $56.7 million development. Construction began in 2018, and the property was ready to welcome tenants in the summer of 2020. “We knew they were the right team,” Carbone said. “Both companies provide indispensable knowledge on Passive House and cutting-edge efficiency standards.”

The Career and Student Success Center on the University of Southern Maine’s Portland campus has a sustainable design on the exterior, with a cross-laminated timber frame and a large photovoltaic array on the roof. Designed for LEED Gold, the facility will anchor a new 1-acre green space with spaces for dining, career development and student connection and is adjacent to a new residence hall designed to Passive House standards. Image courtesy of Elkus Manfredi Architects

The “point” in university buildings

Portland Townships, Portland, Maine

The University of Southern Maine recently broke ground on the largest building project in the school’s history – a $100 million Student Success and Career Center and adjacent Portland Commons residence hall. Both projects are expected to be completed in June 2023.

The 580-bed Portland Commons Residence Hall will be the first student housing on the Portland campus of the University of Southern Maine. Designed to Passive House certification, the 218,000 square foot student residence is expected to use 50% less energy than a comparable structure built to code. Image courtesy of Elkus Manfredi Architects

The 218,000 square foot student housing component is designed to Passive House standards and will use 50% less energy than a comparable structure built to code. It is the second largest passive house college building and the seventh largest in the United States. The adjacent CSSC is designed to LEED standards.

“We’ve designed many buildings over the years to meet various energy efficiency standards, but this is the highest standard we’ve ever aspired to,” said Jeff Jones, principal of Capstone Development Partners, a national student housing organization. Birmingham, Alabama-based developer specializing in public-private partnerships on campus. “It’s cutting edge.”

The residence will have more insulation in the exterior shell than a typical residential building, Jones said, and the HVAC system will be upgraded to improve indoor air quality. “We must follow rigorous installation policies, procedures and practices and inspections throughout the construction process to verify that we are doing everything we can to deliver the energy efficiency that drives the efficiency of the passive house and indoor air quality,” he explained.

The residence will include 580 beds, a communal kitchen, bicycle storage, laundry rooms and an outdoor courtyard. Jones said the development team needed to balance the goal of sustainability with quality and affordability to keep rents affordable for students.

“New construction is getting more and more expensive, especially when you incorporate standards like passive house,” he said. “The key to the success of this project was that everyone was committed to both the sustainability goal and the affordability goal and worked very hard to balance these sometimes competing goals.”

A vibrant mural on the party wall titled “Amaterasu,” the Japanese sun goddess, grounds the building in the neighborhood’s thriving art scene. Image courtesy of Meghan Montgomery with Built Work Photography

Luxury with a focus on health and wellness

Solis, Seattle

Located in the heart of Seattle’s Capitol Hill neighborhood, the 45-unit, six-story Solis apartment building uses 70% less energy than a typical new building. Solis is currently the largest Passive House multi-family building in Washington.

A striking, patterned ‘jewel box’ complements the block’s signature corner with a boutique restaurant, while creating a one-of-a-kind residential entryway. Image courtesy of Meghan Montgomery with Built Work Photography

“It’s a great way to not only reduce your carbon footprint, but also show the world that it’s a profitable business,” said Marc Coluccio, COO of Seattle-based SolTerra, which bought the project for $4.5 million in 2018 and built it. for a total cost of $24.5 million.

Solis was developed by Cascade Built, a Seattle-based development and contracting company, which sold the project but remained the general contractor. The design, which includes studios and one- and two-bedroom apartments, is based on passive house principles to reduce energy consumption and operating costs and prioritize health and well-being. be residents. But it’s also luxurious.

“The units have some of the finest finishes of any apartment building I’ve ever been in,” said Sloan Ritchie, president of Cascade Built. Interior features include engineered wood floors, quartz countertops and modern cabinetry with matte black hardware, he added.

Passive house features include an open-air residential hall and exterior staircase, which reduce heating and cooling loads, continuously filtered fresh air, healthy materials, no air transfer between units, and individual heat pumps.

Common elements include a rooftop terrace with views of Mount Rainier and the Seattle skyline, a fire pit, and a dog run. There are also retail outlets on the ground floor – a wine and chocolate shop, a hair salon and a French bakery and cafe.

Coluccio noted that the sustainability characteristics of Solis helped attract SolTerra to the investment. “This project offers slightly better returns due to lower energy costs,” he said. “It’s just incredibly effective.”

Electricity bills for the entire 45,000 square foot building – apartments and retail – are $700 a month, he added.

Solis has an occupancy rate of 97% and asking rents range from $1,850 to $3,800.

Read the 2021 MHN Mid-Year Guide.