The US buildings sector accounted for two-thirds of the decrease in total energy-related US CO2 emissions in 2019

Top ten cities with the most Energy Star-certified buildings, 2020

Energy Star-certified buildings are verified to be more energy efficient than 75% of similar buildings nationwide, using an average of 35% less energy. The list features solely commercial buildings.

According to BP Statistical Review of World Energy, US CO2 emissions decreased from 5,116.8 million tonnes in 2018 to 4,964.7 million tonnes in 2019.
Source: Energy Star