The decision by the Trump administration to withdraw from the Paris climate agreement ultimately may have little effect on the country’s ability to meet its pledge of reducing domestic greenhouse gas emissions to 26 to 28 percent below 2005 levels by 2025, thanks to several states and cities that have stepped up to the plate.

In June, the U.S. Conference of Mayors (USCM) resolved to continuously strengthen the country’s model building energy code, the International Energy Conservation Code (IECC), by putting it on a glide path to net-zero energy building construction by 2050—that is, each code cycle would be accompanied by progressively higher mandates in efficiency. The resolution recognizes the importance of optimizing building performance, which the November 2017 McKinsey Center for Business and Environment analysis “Focused Acceleration: A Strategic Approach to Climate Action in Cities to 2030” identifies as the most impactful and cost-effective emissions-curbing action a city can take.

According to U.S. Energy Information Administration, the building sector in 2017 consumed 39 percent of the nation’s energy, 28 percent of its natural gas, and 71 percent of its electricity. It also accounted for 36 percent of the country’s greenhouse gas emissions.

Code Catch Up
Published by the International Code Council and revised every three years, the IECC lays out minimum efficiency standards for commercial and residential buildings. Commercial provisions fall into four main sections: building envelope, mechanical systems, electrical power and lighting, and service water heating. Residential provisions are distributed among the first three.

The IECC also references ASHRAE Standard 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings as an alternative compliance path for commercial buildings. Updated triennially on years differing from those for the IECC updates—for example, the 2018 IECC references ASHRAE Standard 90.1-2016—the ASHRAE standard defines efficiencies in six areas: building envelope, HVAC, domestic hot water, power, lighting, and other equipment.

Both the IECC and ASHRAE standards offer multiple compliance paths. Most buildings meet code prescriptively by fulfilling a list of requirements, but “there are also ways where you can trade off, say, more ceiling insulation for less efficient windows but end up in the same place as if you had met the prescriptive checklist,” says Chris Burgess, senior building policy manager at the Midwest Energy Efficiency Alliance (MEEA).

Performance paths offer more design flexibility, but demonstrating compliance requires creating an energy model and thus more time and resources, says Katie Bartolotta, policy and program manager for Green Building United (GBU), a Philadelphia-based nonprofit that promotes sustainability in the built environment. “It’s basically the idea of doing, say, a checklist versus writing an essay on how you achieved the same ends,” she explains.

Performance-based targets, however, may be where codes are headed if all buildings are eventually to be net zero. “You run up against these physical barriers of how you can prescriptively define a net-zero home,” Burgess says. A more likely alternative, he notes, would be: “We want you to get to net zero; you figure out how you get there and prove that you did.”

Jurisdiction Matters
Still, mayors who embrace the USCM resolution may have little say in the energy codes adopted in their jurisdiction. Some states have statewide energy codes that function as both the minimum and maximum efficiency standards. Cities wanting to exceed them have to apply for legislative dispensation.

And while the Energy Conservation and Production Act of 1975 (ECPA) mandates that state energy codes perform as well as or better than the U.S. Department of Energy’s model standards—ASHRAE 90.1 for commercial buildings and the IECC for residential—the process for updating them can take between one and seven years, depending on the state. Because the ECPA also allows states to argue against revising their residential codes, some states may regularly strengthen commercial building requirements but not residential requirements, says William Fay, executive director of Energy Efficient Codes Coalition, which worked closely with the USMC.

In Idaho, inaction at the state level from 2011 to 2017 led 18 jurisdictions to independently adopt more stringent commercial and residential codes than the state code, thus preserving favorable insurance rates. The city of Ketchum, for example, requires the U.S. Green Council Building’s LEED silver certification or the National Green Building Standard silver certification for new residential projects, while Blaine County (which includes Ketchum) applies a sliding Home Energy Rating System (HERS) scale in which larger houses must achieve a HERS score, according to Sharon Patterson Grant, owner of Eco Edge in Ketchum.

But when Boise moved ahead of the state to adopt the 2015 IECC, backlash ensued, Fay says, prompting legislation last year to prevent other jurisdictions from following.

However, he notes, Idaho’s behavior is more the exception than the rule. Progress is being made, even in states with poor adoption records. In June, Philadelphia received a one-time exemption that allowed the city to advance to the 2018 IBC and IECC model codes for commercial construction. The city’s residential buildings and the rest of the state of Pennsylvania will operate under the 2015 edition. The city prioritized the code update as part of a larger climate action plan to cut carbon emissions by 80 percent by 2050. “In Philadelphia, almost 80 percent of our carbon footprint comes from buildings and industry,” says the city’s director of the office of sustainability, Christine Knapp, “so we know we have to tackle buildings as a carbon emitter.”

The uptick in code edition will also lower insurance rates, making the city more competitive, says Michael Fink, chief code official for the city’s department of licenses and inspections. National brands such as Target and Marriott, he says, will find it easier “to do business in Philadelphia if they’re able to get their plans reviewed and approved with a design they already have in place throughout the rest of the country” due to the city’s newfound autonomy.

Both Philadelphia and Pennsylvania are transitioning from the 2009 IECC, which references equipment and technology more than a decade old, Bartolotta says. The key changes include a requirement to select one of eight efficiency packages that detail requirements for HVAC equipment and controls, lighting power density and controls, on-site renewable energy supply, and service water–heating equipment; and adds a commissioning requirement.

GBU has been training the compliance and enforcement communities not only on the contents of the code change but also the adoption process to encourage advocacy. Bartolotta hopes a smooth transition between code editions will help persuade the state to let Philadelphia’s exemption continue into future code cycles.

Some states offer optional stretch codes to encourage building above the state energy code. Massachusetts’ Green Communities Designation and Grant Program offers cities that adopt its stretch energy code technical assistance and grant funding, as well as a road map for cutting carbon emissions by 20 percent in five years. Currently, more than half of the state’s cities and towns are participants.

The 2019 and 2022 editions of the NYC Energy Conservation Code (ECC) will be modeled after the most recent version of New York State’s voluntary stretch code, unless the latter is more than three years old. In that case, the city will revise its ECC code to be 20 percent more efficient than the previous edition. The NYStretch Code—Energy 2018, currently under review, will outperform the IECC 2018’s residential provisions by 25 percent and ASHRAE 90.1-2016 by 18 percent.

Cities Take the Lead
In states without a statewide energy code, some cities have taken a more progressive approach. Columbia, Mo., for example, adopted the 2015 IECC but also requires all new homes to be solar-ready. Most major cities in Arizona and Colorado follow the 2015 or 2018 IECC, Fay says. In addition, Tucson/Pima County has a voluntary net-zero energy building standard.

St. Louis Park, Minn., which aims to be carbon neutral by 2030, has included in its climate action plan an intention to adopt a stretch code if one was established at the state level. The state’s 20th largest city, St. Louis Park “put that in its language as a way to signal that they really want a stretch code,” says Alison Lindberg, MEEA building energy policy manager.

Beyond codes, cities are raising efficiency in their existing building stock through benchmarking. Orlando, whose Mayor Buddy Dyer helped shepherd the USCM resolution, requires owners to track the performance of buildings exceeding 50,000 square feet via the Energy Star Portfolio Manager and to publicly share their score. By 2020, buildings that fall under the national average must either perform an energy audit or retro-commissioning once every five years.

Orlando is one of 20 U.S. cities that have passed such a policy, says Chris Castro, the city’s director of sustainability: “We truly believe this is an important step in achieving a lot of our energy efficiency and sustainability goals because as the saying goes, ‘You can’t manage what you don’t measure.’”

Architects’ Involvement
To help cities reach their goals, architects can educate clients and builders, many of whom are adverse to code changes, for one reason or another. Architects can also advocate for progressive codes and lend their technical expertise to the adoption process.

Although only building officials and ASHRAE Standards Committee members vote on the IECC and the ASHRAE standard, respectively, designers can participate in their development by proposing changes or submitting comments during public review periods. They can also join the IECC residential or commercial energy code committee, which decides whether proposals move forward.