A green building is one that uses less resources and generates less waste compared to a conventional building, while providing healthier spaces. The key differences between brown and green design are mindset, process, and tools. Green buildings focus on sustainable sites, water efficiency, energy management, materials and resources, and indoor environmental quality. Some green building ideas include using AAC blocks, solar PV panels, solar carports, greywater reuse, and combined solar water heating to save resources, costs, and promote sustainability.