A long with construction being reinvented, today’s building professionals are redesigning their job descriptions and skill sets. For example, mechanical designers can no longer get away with saying: “I don’t know anything about control systems or electronics,” or “I don’t have any information on the building’s envelope. It’s not part of the scope of our work.” Younger designers will look at people who make such statements and smile, knowing they will soon be forced into retirement.

Many of the largest construction companies are hiring building scientists, Passive House consultants and mechanical engineers who specify heat pumps, energy recovery ventilators and induction stoves for projects. In a sense, it’s a miracle this is happening.

Back in the day, Milton Hershey, Henry Ford, George Eastman and other industrialists had a seemingly different view of the role of a large company than many of today’s business leaders. As their enterprises grew, the capitalists of yesteryear did not fear being branded as liberals, and they created factory towns for employees that offered housing, schools, hospitals and social services such as care for orphans or those with addiction problems. 

They were not perfect utopias. Sometimes conditions were questionable and workers went on strike, but the original investment attempt constituted a more hands-on approach to corporate responsibility and a clearer understanding that the smartest kind of profit-making enriches society. 

Capitalists are different today. During January of this year, another respected journal revealed that oil companies had very detailed science in the 1970s, 1980s and 1990s, repeatedly verifying that their business was destroying family health and the planet. 

Fossil-fuel companies have accumulated vast wealth during the decades, provided primarily by monthly charges to ordinary people for energy, but rather than using these profits to develop the clean energy technologies that they knew would eventually displace oil and gas, they have doubled down on their dirty business. 

They also invested heavily in fake scientists, engineers and lobbyists to mass-produce techno-babble. It helps delay change and protects massive profits while wildfires, storms and floods destroy homes and farm businesses, keeps children breathing gas fumes in kitchens and diesel fumes on their school buses, keeps everyone paying too much for energy, and poor urban areas full of coal toxins. This continues today. Every day. On a huge scale.

However, the world is changing in spite of it. The planet’s struggling engineers and innovators, the Davids, are beginning to get the better of Goliath. Electric vehicle sales are smashing records. Power generation professionals and markets are rejecting everything but renewables and batteries. President Joe Biden’s legislative actions are creating a historic level of reshoring U.S. production plants for semiconductors, batteries, electric vehicles and solar equipment. And buildings are going electric. 

Embodied Carbon at AHR Expo

At this year’s AHR Expo in Atlanta in February, the ASHRAE education program was dominated by training for low-carbon buildings. Product awards related to cleaner, more sophisticated heat pump systems for bigger projects, sensors and controls that optimize energy efficiency. 

And the next-level, clean-tech topic was in evidence in the exhibits on the show floor: systems and products for tighter, better-insulated building envelopes; lower heating and cooling loads; and new building materials created using less carbon-intense methodologies with reduced dirty energy inputs. 

This latter area is beginning to come to the fore and is known as “embodied carbon.” It’s not normal for mechanical professionals to concern themselves with such things, but as more municipalities establish ordinances around them, some modern mechanical designers will use sophisticated apps to calculate the impact of everything to be used in a new or renovated structure.

For example, an earlier generation of energy-efficiency technologies included chemical spray foams to seal building envelope cracks, but now there is scrutiny on whether these are toxic to indoor air quality or dirty-energy-intense in their manufacture. In the past, mechanical professionals didn’t give a second thought to insulation types or cladding choices when calculating loads or designing systems. 

However, people are working more from home, and their families are suffering from more intense weather events. Customers are now more educated about buildings. Increasingly, mechanical designers are considering embodied carbon and factoring the energy, air quality and resilience impacts of cladding, insulation and structural elements when presenting mechanical options to their customers; or they are specifying them differently in their own design-build projects.

Is embodied carbon significant? During a Passive House Accelerator webinar last year, Nick Shaw reported that in one study, carbon created by a typical building operating for about 30 years, presumably using a gas furnace or similar, was compared to carbon created prior to occupancy of the same house by the materials used to build it — mining, product manufacturing, transportation. 

Analysts estimated that operating carbon was about 40% and embodied carbon about 60%. These numbers undoubtedly vary in different projects and locations in the world, but it’s certainly food for thought on how significant embodied carbon might be.

Tree Bark Cladding 

Embodied carbon and numerous other climate change considerations are in the thoughts of Greg Fisher, a Colorado architect who has been designing LEED, Passive House and other low-carbon homes for nearly 20 years. 

He and his wife, Jeneen, recently decided to downsize, building a new home in which they applied many of the decarbonization initiatives Greg Fisher has been implementing with clients. It’s in Fort Collins, Colo., a small town about an hour north of Denver, nestled in the foothills of the Rocky Mountains and alongside the banks of the Cache la Poudre River.

The couple’s new home is a 3,000-square-foot, fully electrified Passive House, with solar on the roof and a 9.8-kilowatt battery in the garage. Much of it is constructed using low-maintenance, low-embodied carbon, natural materials. An example is the tree bark cladding on the exterior. It came from poplar trees and was supplied by a company called Bark House in North Carolina. 

“It looks, feels and smells very natural, and it’s great in our climate,” Greg Fisher says. “It’s durable, dries out well after it gets wet and, of course, it’s totally biodegradable.”

The project also includes a unique combination of mechanical systems. While most single-family Passive Houses can easily be heated by air-source heat pumps, the couple opted for the comfort of radiant floor heat and the efficiency of a ground-source system. “These decisions were made a few years ago when the jury was still out on air-source effectiveness in cold climates,” Greg Fisher explains. “We both work at home, so we went ahead with a couple of offices and the geothermal.” 

The needed boreholes were only two, each at about 250-feet-deep; Greg Fisher says it was challenging to find a small enough ground-source heat pump. The system would have been much larger without the superior windows, insulation and air tightness of a Passive House. They eventually settled on a 2-ton Nordic unit from Maritime Geothermal in Petitcodiac (near Moncton) in New Brunswick, Canada. 

It was sized right and could provide continuous operating data, a key feature for Greg Fisher, who is tracking all the systems in the house: “I think this is the year we will hit net-zero energy now that we’ve figured out the best ways to run the equipment and we have the battery.” 

He says the house is almost generating as much power as it uses and when it does, they will still have to pay the local utility a fixed monthly hookup charge of $24. This means that during outages caused by intense weather events, they could source their own power or power from the grid to keep the pumps, electric stove, fridge, freezer, lights and offices operating. 

Heating and cooling devices are generally less of a concern in Passive Houses, which can retain livable thermal energy levels for as long as a week or 10 days in some instances.

The solar controls have some intelligence built in so that on normal days, they store about 30% for backup. However, if poor weather is forecast, that information feeds in from the internet, and the controls boost emergency power to 100% in the battery.

“Climate change has been a driving thing for me since around the turn of the millennium,” Greg Fisher notes. “I wouldn’t say I’m a radical environmentalist, but I want to help people do the best they can. Passive House is a sea change while building code is incremental. Eventually, they will meet each other somewhere in the middle; hopefully, sooner rather than later.”

Texas Cork House

“The climate crisis is real and this building makes more sense than drywall, concrete and spray foam, which are common in our industry,” explains Greg Esparza, principal of Moontower Design-Build in Austin, Texas. “My goal was to use only bio-based, plant-based, carbon sequester material, or recycled, recyclable material based on our current understanding of it.” 

For example, helical tiles are used for the foundation rather than a concrete slab, and there is no use of spray foam to fudge or forgive a lack of thoroughness with the air barrier.

“I wanted to use materials that were low carbon, nontoxic and not unhealthy,” he adds. “I didn’t want to design a structure I wouldn’t be comfortable living in myself. My daughter might one day live here and I might live here sometimes, too. And it is also a demo project. It’s difficult to convince clients without an example in practice.”

Esparza explains that the cork acts as both the cladding for the building and the primary insulator. It starts out brown and turns silver over time. “It’s façade-grade and insulation-grade; it’s about 2 inches thick and hits R6.8,” he says. “Under the International Energy Conservation Code, cross-laminated timber (CLT) is considered a solid timber wall with code compliance in this climate. It’s R4, so overall, we have about R12 for total assembly of continuous bio-based insulation, timber, fiber, cork and cellulose.” 

The cork’s 19.5-inch-by-39-foot sheets can be installed quickly and provide seismic durability, fire resistance, low embodied carbon and some carbon absorption over time. Esparza says these materials also create some thermal lag or thermal inertia, meaning it takes a while for the cork to heat up before it radiates into the interior of the structure, similar to a thermal battery.

The house is less than 1,000 square feet of usable space, and the heating and cooling system is a 2-ton Carrier variable refrigerant flow system from the performance line. It’s accompanied by an Ultraire humidity control unit and a Panasonic 100 cubic foot/minute (cfm) energy recovery ventilator running continuously at about 50 cfm.

“I believe we can change the way we approach our work and directly respond to the climate crisis,” Esparza says. “We can improve the health and increase the happiness and well-being of everybody involved in a project, and help the environment, too.”

Cross-Laminated Timber

Esparza notes that the project’s Thermacork comes from Portugal, but the CLT is domestically produced. Although I’m reporting this information on CLT, and although there is great enthusiasm for it in the low-carbon community, I have to admit to a certain amount of skepticism on my part. 

I don’t question the specific studies, but I remember years ago, wood pellets were being called carbon-neutral. For a job I had involving them, I grilled the scientists involved and realized the claims were a bit of a reach. Years later, biomass has a bad reputation for misrepresenting its impact on the climate and the temptation to abuse responsible forestry guidelines has been shown to be too strong near power plants using pellet fuel.

Some of the wood products mentioned here are supposedly Forest Stewardship Council-certified, but this label has experienced some scandals. I understand that selective logging can actually improve forest health and help in management of wildfires, but I’m suspicious about so-called environmentally friendly processes involving big lumber companies and the removal of trees. 

Nevertheless, concrete creates 8% of the world’s carbon, and some drywall products are bad news, too. Chemical spray foams have been shown to contribute to unhealthy indoor air. It’s encouraging that building professionals and mechanical designers are researching and testing new materials and practices that are likely to help in our battle against climate change.