Sustainable projects — including green HVAC — currently account for $134 billion in wages, the study says, and will contribute more than $303 billion to the country’s gross domestic product by 2018.

“Green building is playing a massive role in the U.S. construction sector, the clean and efficient energy sector and the U.S. economy as a whole,” said Rick Fedrizzi, CEO and founding chairman of the USGBC. “More than 2.3 million U.S. workers are taking home $134 billion annually in large part because of green building programs like LEED. Demand for green building will only continue to grow as individuals, businesses and institutions continue to prioritize sustainable approaches to the design, construction and operations of our built environment.”

Sustainable construction projects are boosting state coffers, researchers added. State earnings related to projects certified under the USGBC’s Leadership in Energy and Environmental Design will total $8.4 billion within three years.

“Our research shows that green building has created millions of jobs and contributed hundreds of billions of dollars to the U.S. economy, with the construction of LEED-certified buildings accounting for about 40 percent of green construction’s overall contribution to GDP in 2015,” said David Erne, a senior associate at Booz Allen. “This industry is certainly on the rise, and aggressive growth in the green building sector is anticipated over the next four years.”