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.

This study presents three cost-optimal calculations. The overall aim is to provide a deeper analysis and to provide additional guidance on how to properly implement the cost-optimality methodology in Member States. Without proper guidance and lessons from exemplary case studies using realistic input data (reflecting the likely future development), there is a risk that the cost-optimal methodology may be implemented at suboptimal levels.

The building sector is considered as the biggest single contributor to world energy consumption and greenhouse gas emissions. Therefore, a good understanding of the nature and structure of energy use in buildings is crucial for establishing the adequate future energy and climate change policies. Availability of the updated data is becoming increasingly important in order to allow a rigorous analysis. In this paper, recent data on the world energy consumption in both residential and commercial buildings are reported.