This study presents a summary of green building research through a bibliometric approach. A total of 2980 articles published in 2000–2016 were reviewed and analyzed. The results indicated that green building research had been concentrated on the subject categories of engineering, environmental sciences & ecology, and construction & building technology, and the keywords ‘building envelope’ and ‘living wall’ obtained citation bursts in the recent years.

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.

In 2009, the European Union adopted high-level goals for renewable energy, energy efficiency, and greenhouse gas reductions with targets set toward the year 2020. This was followed in 2012 by adoption of the Energy Efficiency Directive (EED) (2012/27/EU), which included as a major component a requirement for Member States to create Energy Efficiency Obligations Schemes (EEOSs) on energy companies or equivalent alternative measures, and those provisions have now been in effect for three years.