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No longer a niche, Passive House standards becoming a solution for highly efficient affordable housing

A computer rendering of a three story modern building with mural.

As low-income households face the dual burden of weather extremes and high energy costs, energy efficiency is an increasingly important strategy for both climate mitigation and lower utility bills.

Passive House standards — which create a building envelope so tight that central heating and cooling systems may not be needed at all — promise to dramatically slash energy costs, and are starting to appear in “stretch codes” for buildings, including in Massachusetts, Illinois, Washington and New York.

And while some builders are balking at the initial up-front cost, other developers are embracing passive house metrics as a solution for affordable multifamily housing.

“We’re trying to make zero energy, high performing buildings that are healthy and low energy mainstream everywhere,” said Katrin Klingenberg, co-founder and executive director of Passive House Institute-U.S., or Phius. 

Klingenberg says the additional work needed to meet an aggressive efficiency standard, is, in the long run, not that expensive. Constructing a building to passive standards is initially only about 3%-5% more expensive than building a conventional single family home, or 0%-3% more for multifamily construction, according to Phius.

“This is not rocket science… We’re just beefing up the envelope. We’re doing all the good building science, we’re doing all the healthy stuff. We’re downsizing the [heating and cooling] system, and now we need someone to optimize that process,” Klingenberg said. 

Phius in practice and action

A Phius-certified building does not employ a conventional central heating and cooling system. Instead, it depends on an air-tight building envelope, highly efficient ventilation and strategically positioned, high-performance windows to exploit solar gain during both winter and summer and maximize indoor comfort. 

The tight envelope for Phius buildings regulates indoor air temperature, which can be a literal lifesaver when power outages occur during extreme heat waves or cold snaps, said Doug Farr, founder and principal of architecture firm Farr Associates.

Farr pointed to the example of the Academy for Global Citizenship in Chicago, which was built to Phius standards. 

“There was a really cold snap in January. Somehow the power went out [and the building] was without electricity for two or three days. And the internal temperature in the building dropped two degrees over three days.”

Farr said that example shows a clear benefit to high efficiency that justifies the cost.

“You talk about the ultimate resilience where you’re not going to die in a power outage either in the summer or the winter. You know, that’s pretty valuable.” 

There is also a business case to be made for implementing Phius and other sustainability metrics into residential construction, such as lowered bills that can appeal to market-rate buyers and renters, and reduced long-term maintenance costs for building owners. 

AJ Patton, founder and CEO of 548 Enterprise in Chicago, says in response to questions about how to convince developers to consider factors beyond the bottom line, simply, “they shouldn’t.”

Instead, he touts lower operating costs for energy-efficiency metrics rather than climate mitigation when he pitches his projects to his colleagues. 

“I can’t sell people on climate change anymore,” he said. “If you don’t believe by now, the good Lord will catch you when He catch you.

“But if I can sell you on lowering your operating expenses, if I can sell you on the marketability, on the fact that your tenants will have 30%, 40% lower individual expenses, that’s a marketing angle from a developer owner, that’s what I push on my contemporaries,” Patton said. “And then that’s when they say, ‘if you’re telling the truth, and if your construction costs are not more significant than mine, then I’m sold.’”

Phius principles can require specialized materials and building practices, Klingenberg said. But practitioners are working toward finding ways to manage costs by sourcing domestically available materials rather than relying on imports.

“The more experienced an architect [or developer] gets, they understand that they can replace these specialized components with more generic materials and you can get the same effect,” Klingenberg said.

Patton is presently incorporating Phius principles as the lead developer for 3831 W Chicago Avenue, a mixed use development located on Chicago’s West Side. The project, billed as the largest passive house design project in the city to date, will cover an entire city block, incorporating approximately 60 mixed-income residential units and 9,000 sq ft of commercial and community space.

Another project, Sendero Verde, located in the East Harlem neighborhood of New York City, is the largest certified passive-house building in the United States with 709 units. Completed in April, Sendero Verde is designed to provide cool conditions in the summer and warmth during the winter — a vast improvement for the low-income and formerly unhoused individuals and families who live there.

Barriers and potential solutions

Even without large upfront building cost premiums and with the increased impact of economies of scale, improved technology and materials, many developers still feel constrained to cut costs, Farr said.

“There’s entire segments of the development spectrum in housing, even in multifamily housing in Chicago, where if you’re a developer of rental housing time and again …  they feel like they have no choice but to keep things as the construction as cheap as possible because their competitors all do. And then, some architecture firms only work with those ‘powerless’ developers and they get code-compliant buildings.”

But subsidies, such as federal low income housing credits, IRS tax breaks and resources from the Department of Energy also provide a means for developers to square the circle, especially for projects aimed toward very low-income residents. 

Nonetheless, making the numbers work often requires taking a long-term view of development, according to Brian Nowak, principal at Sweetgrass Design Studio in Minnesota. Nowak was the designer for Hillcrest Village, an affordable housing development in Northfield that does not utilize Phius building metrics, but does incorporate net-zero energy usage standards.

“It’s an investment over time, to build resilient, energy-efficient housing,” he told the Energy News Network in June 2023.

“That should be everyone’s goal. And if we don’t, for example, it affects our school system. It affects the employers at Northfield having people that are readily available to come in and fill the jobs that are needed.

“That’s a significant long-term benefit of a project like this. And that is not just your monthly rents on the building; it’s the cost of the utilities as well. When those utilities include your electricity and your heating and cooling that’s a really big deal.”

Developers like Patton are determined to incorporate sustainability metrics into affordable housing and commercial developments both because it’s good business and because it’s the right thing to do.

“I’m not going to solve every issue. I’m going to focus on clean air, clean water, and lowering people’s utility bills. That’s my focus. I’m not going to design the greatest architectural building. I’m not even interested in hiring those type of architects. 

“I had a lived experience of having my heat cut off in the middle of winter. I don’t want that to ever happen to anybody I know ever again,” Patton said. “So if I can lower somebody’s cost of living, that’s my sole focus. And there’s been a boatload of buy-in from that, because those are historically [not] things [present] in the communities I invest in.”

No longer a niche, Passive House standards becoming a solution for highly efficient affordable housing is an article from Energy News Network, a nonprofit news service covering the clean energy transition. If you would like to support us please make a donation.

Massachusetts cities are quickly embracing new emission-slashing building code option

A building under construction in Somerville, Massachusetts.

A year and a half since Massachusetts introduced an optional new building code aimed at lowering fossil fuel use, climate activists are heartened by how quickly cities and towns are adopting the new guidelines. 

The new code, known as the specialized stretch code, became law in 2023. Since then, 45 municipalities representing about 30% of the state’s population have voted to adopt its guidelines. The code is already active in 33 of these communities and scheduled to take effect over the next year in another 12.

“That is just an astounding statistic to me,” said climate advocate Lisa Cunningham, one of the founders of decarbonization nonprofit ZeroCarbonMA. “The rollout has been, quite frankly, amazing.”

Massachusetts has long been a leader in using opt-in building codes to push for decarbonization of the built environment. In 2009, the state introduced the country’s first stretch code, an alternative version of the building code that includes more stringent energy efficiency requirements. Municipalities must vote to adopt the stretch code, and the vast majority have done so: As of June, just 8.5% of residents lived in the 50 towns and cities without a stretch code. 

The specialized stretch code takes this approach a step farther. The goal is to create a code that will help achieve target emissions reductions from 2025 to 2050, when the state aims to be carbon-neutral. In 2021, the legislature called on the state to create an additional opt-in code that would get close to requiring net-zero carbon emissions from new construction. 

“We want to work towards decarbonizing those buildings, right from the start, as we look to a future in 2050 while we are net-zero in greenhouse gas emissions,” said Elizabeth Mahony, commissioner of the Massachusetts Department of Energy Resources.

At the same time, electrified, energy-efficient homes will mean lower energy costs for residents over time, more comfortable and healthier indoor air, and more stable indoor temperatures when power outages occur, she said. 

The construction industry, meanwhile, has concerns about the measure’s impact on upfront costs. 

Getting to net-zero buildings

The resulting code doesn’t require buildings to achieve net-zero emissions right away, but attempts to ensure any new construction will be ready to go carbon-neutral before 2050.

There are a few pathways for compliance. A newly built home can use fossil fuels for space heating, water heating, cooking, or drying or be built fully electrified. If the new home uses any fossil fuels, however, it must be built to a higher energy efficiency standard, be wired to ready the house for future electrification, and include solar panels onsite where feasible. In all cases, homes must be wired for at least one electric vehicle charging station.

Larger, multifamily buildings must be built to Passive House standards, a certification that requires the dramatic reduction of energy use as compared to similar buildings of the same size and type. Single-family homes can also choose to pursue Passive House certification. 

Decarbonization advocates are pleased with the rollout so far. The state’s major cities, including Boston, Worcester, and Cambridge, were all quick to adopt the code. In most municipalities the vote to adopt the specialized code has been near-unanimous, said Cunningham.

And more communities are considering the specialized code.

“We’re talking to a lot of communities that are contemplating it for their town meetings this fall,” Mahony said. “We know there is a growing sense out there of wanting to do this.” 

 The key to convincing cities and towns that the code is a good idea is for municipal governments to understand and frame the code as a consumer protection measure, rather than an added burden, Cunningham said. The requirements of the specialized code along with state and federal incentives can save on construction costs upfront, and will ensure buildings cost less to operate during their lifetime, offering significant benefits to residents, she said. 

“At the point of construction this is an incremental expense – it’s barely even a blip,” she said. “Then it directly reduces your future electricity bills.”

A troublesome transition?

Many in the construction industry, however, disagree with Cunningham’s take. Emerson Clauss III, a director with the Home Builders and Remodelers Association of Massachusetts, has found the equipment needed to reach the high standards in the code is more expensive than its authors counted on, and supply chain issues are causing even higher prices.  

“It’s had quite a rough start to it,” Clauss said. “It’s adding considerable cost to new housing.” 

He also worries that the high cost of electricity now — Massachusetts electricity prices are the third highest in the country — spells near-term financial trouble for homeowners that feel forced to go all-electric. 

“The idea that it’s going to cost less 20 years from now — what does that do for people who need to get into a house now?” he asked.

Furthermore, the creation of a new optional code, he said, adds another variable for builders already jumping between the basic code and the previous stretch code, as well as learning the new rules in ten communities banning fossil fuels as part of a state pilot program. Even municipal building directors aren’t able to keep up, Clauss said, recalling a confused call with a suburban building inspector who needed 20 minutes to confirm it was OK to install a natural gas line in a new home. 

In Cambridge, one of the first cities to adopt the specialized code, Assistant Commissioner of Inspectional Services Jacob Lazzara noted there was some confusion at the outset, but time and proactive communication from the city helped ease the transition. The city has held trainings, created materials to hand out to builders and design professionals, and fine-tuned internal communications to make sure the staff is all well informed. 

“There was a little bit of shock for everyone at first, but I think we’re in a good place right now,” Lazzara said.

Massachusetts cities are quickly embracing new emission-slashing building code option is an article from Energy News Network, a nonprofit news service covering the clean energy transition. If you would like to support us please make a donation.

A St. Paul, Minnesota Habitat for Humanity project will offer affordable housing without fossil fuels

A rendering showing an aerial view of six-story block of apartments with solar panels on the roof.

Construction is underway in St. Paul, Minnesota, on a major affordable housing development that will combine solar, geothermal and all-electric appliances to create one of the region’s largest net-zero communities.

Twin Cities Habitat for Humanity broke ground in June on a four-block, 147-unit project on the site of a former golf course that’s being redeveloped by the city and its port authority, which made the decision to forgo gas hookups. 

Affordable housing and Habitat for Humanity builds in particular have become a front line in the fight over the future of gas. The organization has faced criticism in other communities for accepting fossil fuel industry money and partnering with utilities on “net-zero” homes that include gas appliances. It’s also built several all-electric projects using advanced sustainable construction methods and materials.

The scale of the Twin Cities project is what makes it exciting, according to St. Paul’s chief resilience officer Russ Stark. 

“We’ve had plenty of motivated folks build their own all-electric homes, but they’re one-offs,” he said. “There haven’t been many, if any, at scale.”

Stark added that the project, known as The Heights, was made possible by the federal Inflation Reduction Act. 

“I think it’s fair to say that those pieces couldn’t have all come together without either a much bigger public investment or the Inflation Reduction Act, which ended up being that big public investment,” he said.

A vision emerges

Port Authority President and CEO Todd Hurley said his organization bought the property in 2019 from the Steamfitters Pipefitters Local 455, which maintained it as a golf course until 2017. When no private buyers expressed interest in the property, the Port Authority bought it for $10 million.

Hurley said the Port Authority saw potential for light industrial development and had the experience necessary to deal with mercury pollution from a fungicide the golf course staff sprayed to kill weeds.

“We are a land developer, a brownfield land developer, and one of our missions is to add jobs and tax base around the creation of light industrial jobs,” Hurley said.

The Port Authority worked with the city’s planning department on a master plan that included housing, and it solicited developers to build a mix of market-rate, affordable and low-income units. The housing parcels were eventually sold for $20 million to a private developer, Sherman Associates, which partnered with Habitat and JO Companies, a Black-owned affordable and multi-family housing developer.

“Early on, we identified a very high goal of (becoming) a net zero community,” Hurley said. “Everything we have been working on has been steering towards getting to net zero.”

Twin Cities Habitat President and former St. Paul mayor Chris Coleman said the project met his organization’s strategic plan, which calls for building bigger developments instead of its traditional practice of infilling smaller lots with single-family homes and duplexes. The project will be the largest the organization has ever built in the Twin Cities.

Coleman said the Heights offered an opportunity to fill a need in one of St. Paul’s most diverse and economically challenged neighborhoods and “be part of the biggest investment in the East Side in over 100 years.”

The requirement for all-electric homes merged with Habitat’s goal of constructing more efficient and sustainable homes to drive down utility costs for homeowners, he said. Habitat built solar-ready homes and sees the solar shingles on its homes in The Heights as a potential avenue to producing onsite clean energy.

Zeroing in on net zero

Mike Robertson, a Habitat program manager working on the project, said the organization worked with teams from the Minneapolis-based Center for Energy and Environment on energy modeling.

“The Heights is the first time that we’ve dived into doing an all-electric at scale,” Roberston said. “We have confidence that these houses will perform how they were modeled.”

Habitat plans to build the development to meet the Zero Energy Ready Home Program standards developed by the U.S. Department of Energy. Habitat will use Xcel Energy’s utility rebate and efficiency programs to achieve the highest efficiency and go above and beyond Habitat’s typical home standards.

The improved construction only adds a few thousand dollars to the overall costs and unlocks federal government incentives to help pay for upgrades, he said.

The nonprofit will receive free or reduced-cost products from Andersen Windows & Doors and other manufacturers. GAF Energy LLC, a solar roofing company, will donate solar shingles for over 40 homes and roofing materials. On-site solar will help bring down energy bills for homeowners, he said.

Chad Dipman, Habitat land development director, said the solar shingles should cover between half and 60% of the electricity the homes need. Habitat plans to use Xcel Energy incentive programs to help pay for additional solar shingles needed beyond those donated. 

Habitat will install electric resistance heating technology into air handlers to serve as backup heat for extremely cold days. Dipman said that the air source heat pumps will also provide air conditioning, a feature not available in most Habitat properties in Minnesota.  

Phil Anderson, new homes manager at the Center for Energy and Environment, has worked with Habitat on the project. He said the key to reducing the cost of heating and cooling electric homes is a well-insulated, tight envelope and high-performance windows. Habitat will build on its experience with constructing tight homes over the past decade, he said.

“Overall, the houses that we’ve been part of over the last almost ten years have been very tight homes,” Anderson said. “There’s just not a lot of air escaping.”

Habitat’s national office selected The Heights as this year’s Jimmy & Rosalynn Carter Work Project, named after the former president and his wife, two of Habitat’s most famous supporters. The work project begins September 29th and will receive as visitors Garth Brooks and Trisha Yearwood, who now host the Carters’ program.

Robertson said thousands of volunteers from around the country and the world will help put up the homes. The Heights project “raises a lot of awareness for Habitat and specifically for this development and the decarbonization efforts that we’re putting into it,” he said.

The Heights’s two other housing developers continue raising capital for their projects and hope to break ground by next summer. Habitat believes the project will meet its 2030 completion deadline.

A St. Paul, Minnesota Habitat for Humanity project will offer affordable housing without fossil fuels is an article from Energy News Network, a nonprofit news service covering the clean energy transition. If you would like to support us please make a donation.

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