Historically significant — and inefficient — buildings require extra care to preserve design while saving energy. 

When the Inland Steel Building was completed in 1958, it was the first skyscraper erected in the Chicago Loop since 1934. Beyond the novelty of its very presence in the Loop, the Inland Steel Building incorporated what was at the time an emerging architectural trend — a steel and glass facade with glazed, tinted windows running from floor to ceiling.

The windows presented an especially significant challenge when the building underwent an energy efficiency retrofit beginning in 2016. They are an integral aesthetic feature of the building, which holds both Chicago landmark status and inclusion in the National Register of Historic Places — a  status that restricts any significant alterations in its external appearance. Nonetheless, the building achieved LEED Gold certification in 2018, even without altering or switching out its iconic tinted windows.

“You can do a lot without changing the glass,” said T. Gunny Harboe, principal of Harboe Architects, a Chicago firm specializing in historic preservation and sustainability. “You can do a lot with the mechanical systems alone; upgrading those is a huge improvement because they’re way more efficient. And you know, they run on less energy. And of course, lighting — electrical usage in a building is one of its biggest energy drains. Changing everything over to LEDs saves a huge amount of energy.”

The Inland Steel Building illustrates several unique challenges associated with efforts to retrofit midcentury modernist and postmodernist structures to improve their energy efficiency. And as Chicago and other cities seek to more aggressively clamp down on carbon emissions from buildings, it and other projects show how significant energy savings can be achieved while maintaining design integrity. 

Inland Steel Building

Walter Netsch’s early designs for the Inland Steel Building included a double-glass skin, using space between the panes as ducting for an HVAC system. Despite being far ahead of its time (and still in use today), the double-glass skin was replaced by a tinted glass facade when Bruce Graham took over the project later in the design process.

Because of the building’s landmark status, it was impossible to make what would otherwise have been an obvious move to replace the 1950s windows with more energy efficient multi-paned windows. Instead, the retrofit process focused on upgrading lighting and indoor comfort systems. Once completed, the retrofit process resulted in over 120,000 kilowatt-hours and 3,100 therms in verified savings, equating to over $10,000 in annual cost savings, according to Cate McCormack, vice president and general manager of MB Real Estate.

Specifically, house electric, gas, and water meters in the building are read daily to trend usage and identify any issues that may occur. Steam trap analyses were performed and repairs were made to all that were shown to not operate properly. Lighting was converted to smaller bulbs or LEDs where possible, and occupancy sensors were installed for tenant and mechanical lighting. In addition, a new high-efficiency burner was installed on the boiler, McCormack said.

Federal Center

The Federal Center, another Chicago Modernist landmark, designed by Mies van der Rohe and completed in phases between 1964 and 1974, has undergone several projects to improve energy efficiency. 

The approach the General Services Administration has taken to the Federal Center has been to match the most energy efficient HVAC system with an effective building automation system, while remaining mindful of the need to maintain the aesthetics of the buildings, according to Robert Theel, chief architect for the U.S. General Services Administration’s Great Lakes Region.

A study in the early 2000s found that the building’s mullions (supportive bars separating the glass panels) were responsible for more heat loss and gain than the glazing on the glass itself, Theel explained.

The General Services Administration “realized that adapting a change in glazing would not achieve performance or cost-value analysis goals,” Theel said. “GSA chose to install highly cost-effective solar films on the glazing to lessen the impact of solar heat gain and glare in the summer months. This installation had a minimal impact on the exterior appearance of the glass facades.” 

GSA does not specifically request line-item funding for LEED certification. Nonetheless, its guidelines require projects to seek energy savings and LEED certification whenever possible, according to Theel.

Specifically, $100 million from the 2009 American Recovery and Reinvestment Act for an HVAC upgrade of the Kluczynski building, which received LEED Silver certification. Another $25 million in stimulus funds went toward reconstruction of the Federal Center plaza and below-grade energy efficiency enhancements.

Building automation systems along with LED lighting are also being integrated into existing and upgraded mechanical and electrical systems to achieve more efficient energy usage building-wide, and more effective responses to daily and weekly fluctuations. In addition, Energy Savings Performance Contracts projects — which yield long-term energy savings — have been awarded and installed in both the Dirksen and Kluczynski buildings in the past 10 years, Theel said.

Thompson Center

A newer Postmodern landmark, the James R. Thompson Center (originally the State of Illinois Building), designed by Helmut Jahn, was completed in 1985. Though only 35 years old, the Thompson Center has suffered from years of deferred maintenance, which would require more than $326 million to repair, according to figures cited by the state of Illinois. 

Whether a retrofit can be done cost-effectively is a matter of life or death for the Thompson Center, which does not have recognized landmark status. Any retrofit of the existing building, let alone new construction, would also need to accommodate the busy Clark and Lake transit station, which serves multiple rail lines both above and below ground.

Both former Gov. Bruce Rauner and current Gov. J.B. Pritzker have indicated a strong intention to sell the building rather than spend the funds needed for restoration. As a result, the Thompson Center is a perennial entry on “most endangered” lists for both Preservation Chicago and Landmarks Illinois. And in 2019, the Thompson Center was included in the 11 most endangered buildings nationwide by the National Trust for Historic Preservation.

Plans to sell the building have met with stiff resistance from Ward Miller, executive director for Preservation Chicago, as well as Harboe and other advocates who believe the building merits the necessary investment to bring its HVAC and other elements up to par.

“A new building for the state or rental offices would potentially be even more expensive than repairs to the Thompson Center, when looking at the next 30 to 50 years time. On such a scale as a 17-story building, these repairs and replacement of HVAC systems are all big numbers, but worth it for public buildings and should be budgeted,” Miller said.

Another factor contributing to the relatively poor condition of the building is that a number of shortcuts were taken during construction to reduce cost overruns, according to Miller.

During construction, “one of the items that was ‘value engineered’ was the curvilinear curtain wall, fronting Clark and Randolph Streets — the principal entry to the building from the grand corner plaza,” Miller said. “This glass curtain wall was to be insulated glass — or a double layer of glass, which was an energy efficient material. This was deleted from the program and a more cost-efficient glass was substituted, which did not have the same insulating properties.” 

Indoor comfort in the office areas of the building could be improved by glazing or adding clear glass walls to each floor’s offices, which are now open to the 17-story atrium space that includes a food court. This would also reduce noise and food smells from the building’s open atrium, Miller said.

“Glazing in this location could offer a more controllable climate for each department or office, while still allowing for the transparency of the original design,” Miller explained. “This transparency and nexus of the people of Illinois with their government was an important element of the Thompson Center’s design.” 

Energy efficiency and indoor comfort

The Thompson Center represents a vivid illustration of the energy efficiency and indoor comfort challenges associated with many steel and glass buildings. Rectifying these challenges requires consulting relevant parties and resources, especially if the goal is to achieve LEED, Energy Star or similar certification, according to Matt Akins, manager of HVACR Education for Air Conditioning Contractors of America.

“Whoever’s designing your system — whoever’s going to retrofit that building — they need to consult an architect to figure out what they can and can’t do with the building integrity,” Akins said.

Innovations such as smart thermostats can vastly improve energy efficiency in both retrofits and new construction, but only if they are placed correctly and matched with properly sized equipment, according to Akins.

“A smart thermostat can be a useful tool to help the building owners and the occupants for them to achieve a certain level of comfort,” Akins said. “However, if the system is not sized correctly, the ducts are incorrectly sized or installed and the correct equipment hasn’t been selected for the building … a smart thermostat is only going to offer a very minimal usage to somebody. And if the person puts the thermostat in a wrong spot, for example, on an outside wall, or directly in front of a window, or they put it behind the TV, those readings are going to be off and it’s not going to do you any good.” 

Preservation and landmark challenges

Retrofitting landmarked buildings can introduce conflicts between innovation and preservation, according to Lisa DiChiera, director of advocacy for Landmarks Illinois. 

“There’s always going to be architects who make recommendations for window changes and curtain wall changes in the name of energy efficiency. Where they may choose to recommend a product that they think will be the best performing product, but aesthetically may not be in keeping with the building’s historic integrity,” DiChiera said.

DiChiera noted that Illinois buildings on the National Register of Historic Places may have to be reviewed by both the State Historic Preservation Office in Springfield as well as the National Park Service if certain tax credits or public funding are involved. 

“It’s just a matter of making sure that that conversation is taking place early between an owner’s architecture team and the reviewing architects who have that regulatory review role at the state preservation office and the park service,” DiChiera said. “Indeed, it may still be retaining the original curtain wall, the original glass, but using other kinds of systems with it, or other kinds of improvement.” 

Harboe emphasized the need to consult with multiple sources in executing a retrofit, especially a top-notch mechanical engineer.

“Talking to the architect, you’d want to interview them. What do they want to do? What did they finally do? Are there things in it that we know are flaws? What are the maintenance issues that haven’t been taken care of? Are there problems with the system itself? You have to do a very in-depth documentation and understanding of the historic side. You need to do a physical analysis,” Harboe said.

“And then you’d want to do some energy analyses, some modeling of the building, how does it perform now? How would it perform with a different mechanical system? What kinds of interventions or mitigating factors could you do? You know, if you put film on the glass? If you replaced the glass with something else? There’s a lot of different options.”

For Chicago’s architectural landmarks, retrofits must balance efficiency, integrity 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.

“When technologies don’t align with people’s needs, people don’t use them,” says Virginia Tech assistant professor Philip Agee.

Rookie assistant professor Philip Agee figured academia would be somewhat chaotic. But he never envisioned a germ upending the end of his first academic year at Virginia Tech — and the beginning of his second.

Pandemic precautions mean Agee is once again juggling in-person and online classes in building construction on the Blacksburg, Virginia, campus this semester.

But his lessons on energy efficiency and humans’ relationships with the built environment seem especially germane as the novel coronavirus has elevated conversations about maximizing inside comfort and safety. 

“COVID-19 has caused a lot of misery and hurt,” Agee said. “The silver lining is that it’s putting more emphasis on a healthy indoor environment.”

He grew up in rural Powhatan County, west of Richmond, doing chores on his grandparents’ dairy farm and laboring for a construction contractor during his high school summers.

Virginia Tech — officially known as Virginia Polytechnic Institute and State University — hired Agee in August 2019 right after he completed his dissertation. He teaches undergraduates at the Myers-Lawson School of Construction, which combines architecture and engineering programs under one roof. In tandem, he works with undergraduate and graduate students to conduct in-depth studies for the Virginia Center for Housing Research.

He wants to instill in future engineers and architects the ability to be flexible and open-minded in a sometimes stodgy industry that has to be prodded to evolve. Change matters, he said, because studies he cites reveal that we spend at least 80% of our lives indoors.

When classes began in late August, Agee reminded his students to persevere under less-than-ideal circumstances.

“Adaptability is a muscle that needs to be exercised,” the 35-year-old told them.  “We all have to have a little extra patience and give people breathing room.” 

In this Q&A with the Energy News Network, Agee delves into why society should demand more from its physical surroundings. It has been edited for length and clarity.

Q: First, can you give one example of how the threat of COVID-19 is affecting your approach to this semester? 

A: The way our curriculum is designed is to emphasize experiential learning. Our interdisciplinary approach to construction combines future civil engineers, architects and construction managers. Teaching project management and critical thinking skills is the glue that holds this all together.

One of my classes requires students to prepare a comprehensive preconstruction plan for the recently built $40 million New Classroom Building. Also, our programs will be breaking ground on Hitt Hall in the next few months, which allows us to double the size of our program. Industry partners welcome our students to job sites on campus. That involves interacting with construction crews. It’s one thing to look at blueprints and another to smell, feel and see it, whether it’s the steel frame, the HVAC system or the plumbing.     

I have to divide a class of 50 to 60 people in half, so we’re missing out on sitting down together to talk through questions. It requires Zoom calls, keeping a positive attitude and adapting.

Q: As an undergraduate, you majored in biology at Hampden-Sydney, a small liberal arts college in south-central Virginia. Why biology?

A: In high school, I was outside a lot at my grandparents’ dairy farm, being involved with Future Farmers of America, hunting, fishing, and framing houses and doing carpentry as a summer job.

But I knew I didn’t want to do construction for the rest of my life so I figured I better study hard at college. I knew I wanted to study science because I liked learning about plants and animals and their relationship with the environment.

Q: You did end up in construction, but as a teacher instead of a laborer. How did that happen?

A: Out of college, I worked at an environmental nonprofit before going to a Richmond nonprofit that specialized in energy efficiency and sustainability.

After seven or eight years, I felt like my knowledge was plateauing. I reached out to the Virginia Center for Housing Research and made connections that led me to leave that job and embark on graduate school.

Q: Why is Virginia Tech a good fit?

A: My master’s degree in building construction science management validated how the energy pie was changing. That is, during the 1990s so much energy went to heating and cooling buildings. Now, with so many improvements on that front, I wanted to focus on the human factors for my Ph.D. It’s about how people use the lights, computers and ventilation systems and how to regulate that. We need to recognize that energy use is changing and we don’t need to tolerate poor design.

My joint appointment with the Virginia Center for Housing Research makes for nice cross-pollination. The General Assembly created the center in 1980s to do research, not develop policy.

There are more opportunities here than there is time in the day.

Q: Residential and commercial buildings make up roughly 30% of the greenhouse gas emissions in this country. That’s a drop from peak emissions 15 years ago, but still not stellar. Short of replacing all energy-hog buildings, what needs to happen?

A: That’s a profound question. We have to walk and chew gum at the same time by producing more housing and reducing emissions. For instance, with its affordable housing crisis, Virginia is a microcosm for the country. We need weatherization, education, Energy Star, all kinds of solar, and a better grid.

Very few systems are as opaque as electric bills. Utilities have a long way to go to design systems that provide useful information to users. Every other industry has done that by putting human needs and wants at the center and making them the priority.

Energy efficiency is a goal, but on every level we need to design for the senses and ask whether a certain solution improves a person’s well-being.

Q: Does Virginia have the potential to be a pacesetter on this front?

A: Yes. In some ways, Virginia already is in the Southeast, even though neighboring Maryland is farther along on the building code. Our biggest challenge is on building codes because they fundamentally raise the bar for everyone and are the fastest way to advance this cause.

Virginia is in a pretty good place with solar and we have well-established weatherization programs and providers. Also, if you look at affordable housing in the state, about 300 multifamily rental developments representing roughly 25,000 units have used third-party energy-efficiency programs in pursuit of low-income housing tax credits in the last 10 years.

Q: Zero-energy buildings are a trend, but people assume they are prohibitively expensive. What recent advances have made them less expensive?  

A: The installed cost of solar has fallen 60% over the last five to six years, so that market is mature. We’ve gotten so much better at this that we can build residential buildings that use 50% less energy than a code-built house at the same cost.

Virginia Housing carries the U.S. Department of Energy’s Zero Energy Ready Program as an option for developers pursuing low-income housing tax credits. If such a large-volume producer of residential buildings can do it, then anyone can.

It’s technology that’s here and we can do it. It doesn’t need to be cocktail party conversation, it needs to be the standard. Of course, there would be variations across the state because Hampton Roads has more solar radiation than southwest Virginia. But what makes homes more energy efficient also makes them more comfortable.

Q: You emphasize human factors in construction. Is thinking about the relationship between people and the built environment new or has it been around since humans first sought rudimentary shelter tens of thousands of years ago?

A: Part of this is recognizing that humans and the built environment are linked. Increasingly, we need to design things with people in mind. When technologies don’t align with people’s needs, people don’t use them.

It’s challenging because the construction industry isn’t used to this. The key is, how do you improve the lives of not only the people building the project, but those managing it or living in it? I hope this thinking will be around a long time because that’s the wave I’m riding.

Q: You make it clear that people don’t tolerate suboptimal design with their smartphones, but rarely think about clunky, inefficient buildings. How do you teach your students to pay attention to buildings and care about changing traditional designs and thinking?

A: We get to bring what’s cutting edge in research and transfer it into curriculum and into the classroom. One example is a class on smart-building sensors. It’s a mutual experience because students shape it as well. The students want to have an impact and their enthusiasm drives what we do.

We train critical thinkers to sort through the noise. I get inspiration working with students.

Q: Part of that instruction links your students with weatherization lessons from Community Housing Partners, a leading energy efficiency nonprofit in Christiansburg, Virginia. Why do you continue that relationship that a now-retired professor began several years ago?

A: Community Housing Partners is a nonprofit that is mission-driven so it has a lot of shared values with Virginia Tech and it’s right here in our back yard. It gives students an opportunity to study real projects and see pathways to different careers. 

The program gives students opportunities to go out and experience our industry in different ways. Many students will go to work with large contractors. Part of this is showing students that there’s more to construction than just reinforced concrete and steel buildings in Washington, D.C., and New York City. The ethos of this program is the lesson that people can have a big impact on the built environment, people’s lives in rural communities and improving people’s socioeconomic status.

People like Anthony Cox, the lead trainer at Community Housing Partners Energy Solutions, have always been generous with their knowledge and time. He’s the godfather of building diagnostics and I want my students to meet people who think as creatively as he does.

Q: You mentioned that your relationship with Community Housing Partners is pivoting this semester because the coronavirus has put a temporary damper on hands-on learning. What projects might that entail?

A: We’re playing it by ear and figuring out how to work with Community Housing Partners in other capacities. For instance, we’re developing a data science project to analyze anonymized demographic information collected by low-income housing providers on standardized federal forms. It’s basically analyzing PDFs using machine-learning techniques, so we can do it remotely.

Compiling that information allows us to see who is ready to move out of a rental property and into homeownership. It’s one way to help people out of poverty. We’re starting with Virginia. If we can solve the problem here, it could have a really big impact beyond our state. 

Q: From an energy efficiency and human-scale perspective, what overall grade would you give the buildings on the Virginia Tech campus?

A: I’m not going to touch that one. I will say that Virginia Tech has a pretty comprehensive sustainability program that is student-driven and faculty-supported.

Q: Can you offer an example? 

A: Yes. One of our graduate students wrote a proposal for a project to address classroom space needs. At several places across campus, students can now sit outside at covered metal tables where part of the canopy is a solar panel that powers a charging station. It’s renewable infrastructure that contributes to energy literacy because everybody can see the electricity source. A local company designed them with the university colors and logo.  

Q&A: Virginia construction professor puts people at center of efficient design 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.

Michael Sorkin died this spring, but partners on Chicago’s South Side are determined to make his net-zero plans a reality.

A Chicago nonprofit is forging ahead with an energy efficient housing project, despite the loss of a key partner earlier this year to COVID-19. 

With ongoing unrest across the country, there has been a growing emphasis on social justice issues such as affordable housing and revitalizing disinvested neighborhoods. For Naomi Davis, founder of Blacks in Green on Chicago’s South Side, this is familiar territory. She and her organization have been focused on these areas for a dozen years, with an added emphasis on energy efficiency and sustainable development. 

However, the work of Blacks in Green has been disrupted by the death of architect Michael Sorkin, a professor of urban design at the City College of New York. Sorkin was also the founder of Terreform, a nonprofit organization specializing in urban environmental research. He had been working with Davis and Blacks in Green on the BIG Green Homestead — a projected development of affordable housing to be located in the West Woodlawn neighborhood — before he succumbed to COVID-19 in March 2020.

“Michael introduced himself to me by email on December 28, 2016 with an invitation to join his panel for Promising Developments,” Davis wrote in an email message distributed shortly after Sorkin’s death. “I’d heard of him during the international design bids to win the Obama Presidential Center commission. Michael had filed one of his famous ‘amicus curiae’ designs but he was just as interested in a radical rethink of housing for black folks.

“He was an exciting brainstormer. Within days, we were talking partnership. Within a year, we’d gone from ‘Comrade’ to ‘Cousin,’ and soon to our perpetual shorthand ‘Cuz!’ We were kin before I fully realized his celebrity or genius.” 

The BIG Green Homestead development aspires toward a net-zero footprint by combining a number of features, including enhanced daylighting, onsite wastewater recycling, energy efficient construction materials and solar energy — all set within a walkable neighborhood environment. The proposed development is a modification of Sorkin’s Greenfill: House as a Garden concept, which was one of five finalists in a 2019 design competition to reimagine housing on small lots in New York. 

Sorkin had submitted a detailed set of renderings and architectural plans to Davis in early March, just before he died. The project, which is still in the early planning phases, aspires to attract middle-income residents. BIG already owns the site slated for the development — having purchased it for $1 through a city program to encourage development on vacant property, Davis said.

“We’re looking at how to make our numbers work outside traditional housing finance across an AMI [area median income] spectrum from 60-80% for owner/occupants and 30-60% for renters,” Davis said. “We are creating these sustainable square miles. We’re creating this walk to work, walk to shop, walk to learn, walk to play village, where African American people live, where they own the businesses. They own the land. And they live the conservation lifestyle.”

Other members of the team behind the planning of the BIG Green Homestead include Ellen Grimes, an architect and instructor for the School of the Art Institute and Tracy Sanders, an urban planner and civic impact specialist from the architecture firm WXY in New York.

The BIG Green Homestead is one of several moving parts associated with Davis’ holistic sustainable vision for revitalizing West Woodlawn. Other initiatives include the Green Living Room, developed in collaboration with Commonwealth Edison; and the nation’s first African American Community Arboretum, in partnership with the Morton Arboretum.

While coronavirus restrictions have made progress difficult, Davis is determined to resume moving forward with Sorkin’s design, including planting a signature tree in his memory in the Orchard of the Elders.

“He gave us those renderings the week before he went in the hospital and died,” Davis said. “Here Naomi, this is about $100,000 worth of work; let’s get this thing built.”

Efficient housing project moves forward in Chicago despite loss of key architect 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.

Supporters are optimistic that the City Council will adopt a 2021 code expected to increase efficiency by 10%.

After years of lagging other cities on energy efficiency, Kansas City, Missouri officials have taken a step that could result in the city adopting the toughest building code in the country.

Since 2012, the city has operated with a building code that was weakened to meet the desires of the home building industry. The local architectural community and other clean energy promoters have been pushing the Kansas City Council to make a leap toward greater efficiency in all new construction. 

Last Thursday, the council adopted updates to the building code based on a set of universal standards published in 2018. But the council deferred action on energy efficiency provisions in anticipation of an updated 2021 code to be released later this year. 

While it’s not assured that the council will adopt the tougher standard, advocates are optimistic.

“We couldn’t have asked for a better outcome,” said Joyce Raybuck, a local architect who was one of the leaders in the campaign for the 2021 code. 

Councilmember Andrea Bough, who introduced the language to vote later on the efficiency piece, said several of her colleagues on the council “have publicly expressed support” of the 2021 efficiency standards. However, “I cannot say at this point if the votes are there to adopt 2021 over 2018 because we haven’t had those discussions with all of the council members.”

Raybuck sees a stronger efficiency standard aligning with other climate developments in the area. A month ago, the Kansas City Council updated its climate protection plan with a commitment to becoming carbon neutral by 2040. A regional climate action group plans to release an action plan in December.

“There are several things happening that this ties in well with,” Raybuck said. “We are confident [the 2021 energy efficiency code] will pass if the council is committed to the things they say they are committed to.”

The council won’t be able to take action until early 2021. The new code is to be published in October, after which the council will have to wait 90 days before taking up the matter. Raybuck expects the city will conduct a public process and seek feedback before taking a vote.

Other clean energy activists took heart in Thursday’s vote.

“This action shows that Kansas City is serious about achieving its climate action goals,” said Billy Davies, conservation organizer for the Sierra Club’s Missouri chapter. “It is important that we not waste easy opportunities that can help protect public health [and] reduce greenhouse gas emissions, like evaluating and adopting state-of-the-art energy efficiency codes.”

The International Code Council every three years revises model building codes that cover all aspects of construction, but local governments have discretion over which, if any, of the updates they enforce. The Kansas City Council adopted most of the 2018 version of the international building code on Thursday, but agreed to wait until fall when it will have the option of the 2021 version of the energy efficiency code.

It matters because the 2021 efficiency language is expected to increase efficiency by 10% over the 2018 standards. The last few versions of the international energy efficiency code have made almost no change in the required efficiency of new buildings, a lapse that the New York Times attributed to the large presence of the home building industry on two powerful committees that approve the international standards.

The 2021 version also will include a new feature: a “ZERO code” that, if adopted by a local governing body, would require developers of commercial, institutional or mid-or high-rise residential buildings to obtain all needed energy from renewable sources. The power could be generated on-site or purchased from a utility.

If the city adopts the 2021 version of the energy efficiency code in the fall, it will be a dramatic shift from the city’s present requirements. In 2012, the city adopted that year’s code language in large part, but made a couple of important modifications. It allows homes to have four inches of insulation in the exterior walls rather than the six inches mandated by the international code. Kansas City rules also permit more exchanges of air — leaks — than the international code: five exchanges per hour in Kansas City, three per hour in the international code.

International code requires a blower-door test to calculate how much air leaks into a structure. Kansas City’s amended version allows the codes department to determine the need for the test.The local home builders industry pressed hard for the weakened standards, contending that higher costs would chase home construction to the suburbs where, according to one local home builder, standards are comparable to Kansas City’s current weakened law. Approximately 500 homes typically are built in Kansas City in one year. The Home Builders Association of Greater Kansas City did not respond to interview requests.

Kansas City poised to adopt the most efficient building code in the country 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.

In Boston, two firms designing affordable housing using cross-laminated timber hope it can be replicated elsewhere.

Sustainable engineered wood products are starting to turn up in large-scale construction projects in New England, as architects, developers and institutions look for ways to reduce the building industry’s substantial carbon footprint.

Cross-laminated timber, or CLT, and other so-called mass timber products are viewed as greener than concrete and steel, primarily because the carbon emissions from production of the wooden framing materials is so much lower.

Since the University of Massachusetts incorporated CLT construction to stunning effect in its Design Building on the Amherst campus three years ago, the material has turned up in a number of other large projects, including a new residence hall at the Rhode Island School of Design, in Providence, and an office building under construction in Newington, New Hampshire.

Now, two firms designing an affordable housing project implementing CLT in Boston hope it will become a prototype for sustainable architecture that can be replicated by other developers in housing throughout the city.

“Boston has a very progressive design, engineering, construction and development community, and carbon is the new hot topic,” said John Klein, chief executive officer of Generate Architecture + Technologies, a startup focused on mass-timber building solutions based at the Massachusetts Institute of Technology.

Cross-laminated timber is a very large, prefabricated wood panel. It is formed of several layers of lumber boards, stacked in alternating directions and glued to form one panel. Much stronger than traditional lumber, CLT is suitable for constructing walls, roofs and floors.

First introduced in the 1990s, CLT is widely used across Europe but has only started to catch on in the U.S. in recent years. It is sometimes used in conjunction with some steel or concrete.

Tom Chung, a principal at Leers Weinzapfel Associates, the Boston firm that designed the U-Mass building, said he’s an advocate for three reasons, starting with the environmental benefits.

CLT is a renewable resource, provided that the wood used to make the products comes from a sustainably managed forest, as verified by third-party certification, he said. And the production process is much less carbon-intensive compared to concrete or steel. (The cement sector alone, which is critical to production of concrete, is the second largest industrial CO2 emitter globally, according to the International Energy Agency.)

Second, the CLT is usually exposed in the building interiors, as the wood is aesthetically pleasing. And that adds to a building’s sustainability because construction requires fewer resources — “you don’t have to have additional materials to cover up the structure.”

And finally, because the products are prefabricated in a factory, the process of assembling the building is faster, quieter and results in less construction waste, he said.

“There’s always going to be a place for concrete in buildings — it’s good for foundations. And steel has the advantage for long spans and other complicated geometries of tall buildings,” Chung said. “But mass timber overall makes sense in your typical six- to 12-story building. That’s where it makes the greatest contribution in reducing our carbon footprint.”

The firm has since designed what it says is the largest CLT building in the United States — a 200,000-square-foot residence hall at the University of Arkansas.

Frank Lowenstein, deputy director of the New England Forestry Foundation, says buildings constructed with CLT also effectively function as carbon sinks, since trees store carbon dioxide in their wood.

“You’re taking wood from the forest and locking that carbon up in the building for the life of the building,” he said. “The carbon that’s stored in the forest is less secure due to the potential for fires, clearing, etc.”

Increased demand for CLT could eventually drive its production in New England. And that, Lowenstein said, would create a financial incentive for landowners to grow the larger trees needed for its manufacture, and enhance now-depleted forests’ carbon-storing capacity.

“The economics right now don’t reward people sufficiently for landowners to change practices and start storing more wood,” he said.

In Boston, Generate Architecture has partnered with Placetailor, an integrated development, design and construction company focused on carbon-neutral housing, to come up with a replicable prototype for high-density, mass-timber building approaches.

The companies hope to begin construction this summer on a five-story, 14-unit affordable housing development with a ground-floor, affordable coworking space in the city’s Roxbury section.

The digitally designed and digitally fabricated structure is intended to meet passive house and zero-emission standards. It will also serve as “a mock-up of sorts” for other builders to learn from, Klein said.

“The structure is cellular, like a beehive,” he said. “If you cut across you would see this really interesting honeycomb of these plates. You can use them for the walls, the envelopes, the elevator shaft. And once you have one floor up, you can repeat it, one on top of the other.”

The replicability aspect of the project is crucial to transforming future housing construction in Boston, said Colin Booth, Placetailor’s strategic director.

“Something that any developer can take and work with — the import of that can’t be overstated,” Booth said. “Boston is setting some very progressive carbon-reduction goals, and projects like this offer them case studies in innovations that are going to help transform construction to align toward those goals.”

Critical mass: Can low-carbon wood construction catch on in the U.S.? 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.