In its effort to promote best practices in sustainable design and development in the 2018 MFE Concept Community, developer AMLI Residential and architecture firm Skidmore, Owings & Merrill (SOM) worked with the team at the Passive House Institute US (PHIUS) to design the project to PHIUS certification standards. The undertaking encompassed cutting-edge innovation and technologies to reach optimal standards in energy performance.
As part of the process, the PHIUS team conducted a feasibility study for the Concept Community, Building Positive + Living Well, that determined general levels of performance the AMLI–SOM team should aim for to enable the community to meet PHIUS standards, known as PHIUS+. The standards cover components such as building envelope, mechanical systems, and renewable-energy generation potential. Climate, occupant density, and building typology are also considered.
The project was initially reviewed using PHIUS+ 2015 standards but was also able to benefit from the new, PHIUS+ 2018 standards, which include the ability to recognize a variety of renewables as offsets, including all on-site generation, directly owned off-site renewables, community renewable energy, virtual power purchase agreements, and green-E certified renewable energy certificates discounted 80%. The Concept Community design was modeled at 60% on-site renewable energy and 40% off-site renewable.
The Envelope, Please
PHIUS focused the Concept Community's design review on the project's window glazing, offering multiple variations and levels of efficiency to meet specific space-conditioning criteria.
“With the project’s targets, we had to focus on the envelope first and then reduce the energy needed to satisfy the remaining loads,” says Lisa White, a certification manager at PHIUS. “The mechanical systems here are good; you can’t get much better. But for example, improving the windows first was require to meet PHIUS targets for heating load.”
With its triple-glazed windows, building-envelope innovations, and state-of-the-art mechanical systems, the MFE Concept Community reached an EUI (energy use intensity) level of 21.3 using the WUFI Passive software model, falling within the high-performance range of 20 to 25.
“We added quantum dot coating to all the windows to collect solar; rooftop solar thermal; and garage-top PV [photovoltaics], ultimately to total about 60% of the energy required on-site from solar,” says Luke Leung, director at SOM.
Understandably, given its high standards, the PHIUS program presents several challenges to participants.
“One challenge to meeting PHIUS certifications may be the program's strict performance targets,” says White. “Also, ensuring that everyone is on board and on the same page throughout the full design process and through construction is a challenge, but it's one that can be overcome with thoughtful planning and coordination.”
Overcoming misconceptions about the cost of certified versus noncertified properties can pose another hurdle.
“The second most-challenging aspect is overcoming the perception that passive buildings cost more,” says Katrin Klingenberg, PHIUS's executive director. “Understanding that, in large passive projects, the budget can be the same as for an energy code baseline building is key. This is where the development team's experience in integrating high-performance design strategies really starts to pay off: Development, design, and construction are coordinated to work hand in hand for the best possible outcome at the lowest possible cost. The outcome, if done right, is an economical slam dunk.”
To tackle these challenges head on, SOM relied on its diversified, in-house multidisciplinary team, which focuses on high-performance design and deals with the many, and varied, green certifications available in the housing industry. “Both engineers and architects are on our performance team, to cover the left- and right-brain issues,” says Leung.
Another good example of the benefits of PHIUS certification in multifamily communities lies in the 2016 Rockaways, Beach Green Dunes project in Queens, N.Y., by developer Steve Bluestone. At the time, it was the first and largest affordable certified multifamily project in North America, with 101 units, and was completed at just 1% above the cost of an Energy Star baseline. Yet, the PHIUS+ certified building saves an estimated 40% more energy than a comparable Energy Star baseline building.
What’s in the Future?
When Leung thinks about the future, he envisions a super-sophisticated green modeling and certification process.
“Hopefully, [PHIUS certification] will evolve to include passive embodied material, passive thermal/energy storage, and passive design, including the context of a building, while balancing low energy consumption with quantifiable wellness, including outside air and daylighting,” he says.
White, meanwhile, is excited about focusing more on building mechanical systems, especially hot-water systems, to make them perform more dynamically.
“The biggest room for improvement is hot-water systems, in both the delivery and the systems efficiency,” she says. “Hot water is the next low hanging fruit for innovation. It's kind of the next big thing in terms of systems that have yet to be transformed.”
For deeper insight on the Building Positive + Living Well project, visit www.multfamilyexecutive.com/concept-community.