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.

Academicians and professionals in the architecture, engineering, and construction (AEC) field have expressed an increasing interest in sustainability and its application in the development of construction projects, especially with its deemed relationship with lean construction, for the purpose of improving efficiency in the construction processes. Practices framed under the lean philosophy show their potential in reducing environmental, economic, and social impacts during the construction phase, with an increase in the parameters of sustainability in the development of projects.

An overview of climate change mitigation opportunities in the world's buildings is presented, based on the key building-specific findings of the Fourth Assessment Report from the Intergovernmental Panel of Climate Change. Buildings and the building stock can play a major role in mitigating climate change in the short- to medium-term, since substantial reductions in CO2 emissions from their energy use can be achieved over the coming years.