In this article you can get a general idea of what a Green Building is. According to U.S. EPA “Green Building is the practice of creating structures and using processes that are environmentally responsible and resource-efficient throughout a building’s life-cycle. […] Green buildings I s also known as a sustainable or high-performance building.”
The author explains the environmental and economic benefits as well as the goals of Green Buildings.
You may read the article at https://www.conserve-energy-future.com/green-building.php.