3 Cities Win Coveted Sustainability Award

These cities were dubbed best sustainable cities of 2026 by Green Builder magazine editors. Here's what makes them standouts. 

When should a city establish a sustainability policy? Should it be as the first municipality out of the gate, setting an example for others to follow? Or should a city wait until it sees that example? And what can a city do to not appear to be late to the game? 

The winners of Green Builder’s 2026 Most Sustainable Cities category fall into one or more of these scenarios. The three recipients represent different-sized locales: Large (Buffalo, New York), Medium (Kansas City, Missouri), and Small (Piedmont, California). But they’re all tackling the question of how they can best become a leader by demonstrating—and promoting—environmental correctness. 

Whether it’s because of a desire to reveal a new technique, or the need to adjust to the needs of a changing demographic, or to simply find a way to refresh a tried-and-true method, our winners have their answers. Will they be yours?

Large-sized Municipality (250,000+ population): Buffalo, New York 

The West Side Homes project, dedicated to providing affordable, high-performance green housing to lower-income Buffalo residents, was completed in late 2025. Units were built to standards such as Passive House, ENERGY STAR, U.S. Department of Energy (DOE) Zero Energy Ready Home (ZERH), and EPA Indoor AirPlus. CREDIT: Sustainable Comfort

In 2019, Buffalo Mayor Byron Brown made an offhand comment in his annual State of the City Address, saying that Buffalo would soon become “a Climate Refuge City.” Seven years later, the municipality has made major strides toward achieving that goal.

Buffalo, which at roughly 280,000 residents is the second-most populated city in New York, has reversed decades of decline with help from Mother Nature and city sustainability efforts. The local population has increased by about 20,000 since 2020, the first gain since 1950, according to U.S. Census data.

Over the past 8 years, the city has received thousands of migrants from areas regularly stricken by natural disasters such as hurricanes, floods, tornadoes, wildfires and inclement weather, according to a report in Yale Climate Connections. This, despite being among the coldest cities in the nation—Buffalo sees an average of 100 inches of snowfall per year, according to a study from Harvard University. But Buffalo is also the only city of more than 100,000 population in the continental U.S. to have never experienced a 100-degree (Fahrenheit) day. Weather experts attribute this to Buffalo’s climate-contained location on the Northeast edge of Lake Erie. 

As with elsewhere in the U.S., climate change effects are being experienced in Buffalo, but at a much slower rate, according to Stephen Vermette, a professor of geography at Buffalo State University. For people coming from harsh weather-hit locales such as Florida, Texas or California, moving to a place with a seemingly stable—and predictable—climate seems like a no-brainer. As a result, Buffalo and several other Great Lakes Region cities have been given the nickname of a “climate refuge.”

It’s a term that economic development organizations are using to attract new business. For example, Invest Buffalo Niagara’s “Be in Buffalo” talent attraction program stresses beneficial factors such as exceptional air quality, the city’s near-zero high ozone days per year, and even the lack of risk from global sea level increase due to climate change.

Green business growth abounds. There’s the big: In 2020, the city succeeded in attracting fuel cell company Plug Power, which planned to build a $290 million green hydrogen power plant. The facility would have been the largest in North America and was expected to generate 45 metric tons of clean electricity per year in the Buffalo-Rochester, N.Y. area. The project was cancelled in 2025 after federal funding was cut.

And then there’s the small: In recent years, “zero waste” stores such as Little Salmon, and Clean Collective, both of which offer essential products made from ethical and renewable sources, and services such as Green Buffalo Lawn Care, which provides low-cost eco-friendly lawn treatment, have opened or expanded to Buffalo.  

In 2022, Buffalo was designated one of New York’s Climate Smart Communities, which is granted to cities that take steps to cut carbon pollution and prepare for extreme weather. The city’s actions include installing LED streetlights, placing solar panels on city buildings, upgrading the sewer system to better guard against flooding, and adding porous pavement and parks that can soak up rain. 

Buffalo is also continuing to increase and improve affordable housing through sustainable methods. In 2025, nonprofit community sustainability organization, PUSH Buffalo completed its $23 million West Side Homes project, a 49-unit affordable housing development that was built to net-zero or Passive House standards. The effort, which included using ground source heat pump systems, energy recovery ventilation, and rooftop solar panels, lowered heating and cooling expenses for residents and helped reduce the region’s carbon footprint, according to PUSH Buffalo Executive Director Dawn Wells-Clyburn.

Even real estate is getting on board. For the second consecutive year, market analyst Zillow has named Buffalo as the nation’s hottest housing market, largely because competition for homes hasn’t cooled, according to economic analyst Anushna Prakish. The migration of out-of-state homebuyers to the city, continued housing affordability, the region’s growing economy, and ongoing emphasis on sustainability are “proving to be attractive draws,” Zillow notes. 

Medium-sized Municipality (100,000-249,999 population): Kansas City, Missouri 

The Roy Blunt Luminary Park will reduce street level heat, plus encourage upgrades to retaining walls, drainage, pavement, and more. CREDIT: OJB

Kansas City’s recent efforts to promote and implement sustainability among its residents have garnered a lot of attention from the public, including efforts to more aggressively manage the sudden boom in AI data centers.

There are more than 30 data centers either completed or in development in the Kansas City area. Some of these, such as Google’s $1 billion proposed center, leverage renewable energy to power their operations. This would reduce burden on the city’s power grid by about 20 percent, according to Google officials.

However, most data centers run on electricity generated from fossil fuels. These all release significant amounts of carbon dioxide (CO2) and other greenhouse gases (GHGs), contributing to climate change. Even the Google site, still under development and possibly not online until 2027, will require approximately 450,000 gallons of water per day to operate. This can strain local water resources, especially in areas prone to drought or with limited water supply, Kansas City government officials note. 

That’s why city officials in January approved an ordinance that limits where data centers can be built and their maximum sizes for a given construction area. The city’s next action will be to examine the impact of data centers on the city’s environmental quality, water rates, economic growth and financial incentive process.

Data center management isn’t the only way Kansas City has demonstrated its green tendencies. In 2023, the efforts earned LEED for Cities Gold certification from the U.S. Green Building Council (USGBC). The efforts include the Climate Protection and Resiliency Plan (CPRP), designed to help reduce GHGs emissions and achieve climate neutrality for city operations by 2030 and citywide by 2040; converting its fleet of government vehicles to all-electric ones where available; replacing nearly 100,000 streetlights citywide with energy-efficient LEDs; and beginning purchase of renewable energy to help save Kansas City close to $1.5 million in energy costs since 2020.

In 2024, Kansas City became a Bloomberg American Sustainable City (BASC), an initiative designed to help K.C. and other winning cities access federal funds to support climate action and economic development. Much of that funding is meant for critical projects in disadvantaged communities, including affordable housing, electric vehicle investments, and clean energy access.

Meanwhile, the city has edged closer toward its goal of reaching citywide climate neutrality within the next 15 years. According to Kansas City Mayor Quinton Lucas, the city is more than 25 percent of the way there. It will continue to “work with community partners to ensure we’re building a more-resilient energy system for the future.”

Following its own success, Kansas City now requires new city facilities and renovations exceeding 5,000 square feet to achieve LEED Gold certification to lower energy consumption, reduce carbon footprints, and ensure a good long-term environmental impact.

A prime example is the new Kansas City International Airport terminal, which in 2023 became the nation’s second airport to receive LEED Gold certification. It is powered entirely by renewable energy, and is the first airport to offer wireless bus charging. The project also diverted 85 percent of all construction waste from landfill when dismantling the old terminal building to build the new one, according to a report by USGBC.

Next to the airport is another high-profile sustainable project: a proposed 2,000-acre solar farm. It would produce sufficient electricity to power 70,000 houses, making it one of the nation’s largest solar farms. Originally proposed in 2021 and expected to be under construction starting in 2023, city officials hoped to have the farm completed before this summer, when the FIFA World Cup comes to town. But various setbacks may push the start date to early 2027, the city notes.

Kansas City also has several projects underway that demonstrate a commitment to sustainable development. Nearly complete is the Roy Blunt Luminary Park, a $217 million, 5.5-acre urban park that is meant to improve walkability between the city’s business district and its arts district, as well as offer a way to reduce the “urban heat island effect” through use of shade trees and natural foliage. The project also involves critical upgrades to aging infrastructure, including retaining walls, drainage, pavement, and a nearby bridge. 

Small-sized Municipality (Less than 100,000 population): Piedmont, California 

Once known as “The City of Millionaires,” Piedmont, California is now a leading example of how to implement a carbon emissions reduction plan. CREDIT: City of Piedmont

Back in the 1920s, Piedmont, California was known as “The City of Millionaires” because it had the largest number of ultra-wealthy per square mile in the United States. One-hundred years later, the tiny San Francisco Bay Area city of 11,200 residents may have earned another nickname: “Climate Action City.”

The city adopted its first Climate Action Plan—a strategy to reduce greenhouse gas (GHG) emissions and develop climate adaptation measures—in 2010. This plan focused on energy efficiency and set modest 20-year GHG reduction goals. A more-ambitious CAP was adopted in 2018; this one emphasized decarbonization and called for cutting greenhouse gas emissions by 40 percent by 2030 and by 80 percent by 2050.

Most homes in Piedmont are “vintage,” with 90 percent at 60 years old or more, and 65 percent approaching 100. All of these were primarily powered by natural gas and were poorly insulated, making electrification and remodeling top priorities.

Under CAP 2.0, Piedmont’s municipal and residential utility accounts were enrolled into a 100 percent renewable energy service plan in 2018 to reduce the GHG production. Utility bills also dropped, which “certainly no one was unhappy about,” the City notes.

Meanwhile, extensive residential retrofits became a fact of life. Suggestions and feedback from residents, business owners, contractors and other stakeholders were collected at workshops and town halls, and via public surveys. “We were committed to capturing a comprehensive reflection of perspectives from the community and were gratified at the strong support, consistently ranging around two-thirds of survey participants,” the City notes.

By 2021, an approved list of requirements, or “reach codes,” went to builders of new structures and renovators of older ones. These surpassed requirements by the State of California.

Newly constructed low-rise residential buildings, including new detached accessory dwelling units (ADUs), must use all-electric building appliances. Projects proposing an entire new upper level on a low-rise residential building, or that increase a low-rise residential building’s total roof area by 30 percent or more, are required to install solar panels on the roof. 

In terms of existing home retrofits, electrical panel upgrades must include capacity to accommodate future electrification of all appliances in the residence. LED lamps and vacancy sensors must be installed. A gas furnace must be replaced with an electric heat pump system, and a gas water heater must give way to an electric heat pump water heater. Insulation of at least R-3 (hot water piping), R-19 (raised floor assemblies), and R-38 (attics and air ducts) must be used. Electric vehicle (EV) charging circuits must be installed.

If the home was ever sold, a report from a home energy audit must be provided to potential buyers and submitted to the city, unless the residential building was constructed in the past 10 years. 

The “Piedmont Climate Challenge” platform was launched to help residents measure and reduce their carbon footprints. Occupants can also use the platform to have a friendly competition: Which residents can reduce their carbon footprint the most? 

In 2021, the City Council adopted an update to the Pedestrian and Bicycle Master Plan, with an additional focus on general traffic safety. The City also emphasizes community education through information sessions and resource sharing across sustainability topics, including EV funding, green building, home electrification, eco-friendly landscaping, and more.

The City Council also unveiled plans for an all-electric community pool in 2022, making Piedmont one of the first cities in California to do so. Officials estimated completion by early 2024, but various delays have left the project in limbo. The accompanying pool facility is also being evaluated for U.S. Green Building Council (USGBC) LEED certification, another first for the city.

An amended version of CAP 2.0 was released in 2023, setting new goals of 50 percent GHG reduction by 2030 and achievement of carbon neutrality no later than 2045. City officials are confident the goals will be met.

“Climate change is a human-induced global crisis that is currently causing environmental, economic, and social misfortune and inequity,” the City notes. “The residents of Piedmont recognize that we must all take action to reduce greenhouse gas (GHG) emissions through electrifying homes, driving gasoline cars less, and purchasing goods and services more responsibly. By acting locally, our small city can make a contribution to a worldwide effort.”