In an era of U.S. energy abundance, the persistently high energy bills paid by low-income households is troubling. After decades of weatherization and bill-payment programs, low-income households still spend a higher percent of their income on electricity and gas bills than any other income group. Their energy burden is not declining, and it remains persistently high in particular geographies such as the South, rural America, and minority communities.

With the high growth urbanization and increasing new urban population, the huge demand for infrastructures and dwellings has become a great challenge for the sustainable development in Chinese cities. The building sector shares one fourth of total energy consumption in the country and plays an important role in reducing the energy consumption and the consequential greenhouse gas (GHG) emissions. Some policies have been issued for promoting the low carbon sustainable development in China's buildings.