This report addresses the single largest source of greenhouse gas emissions and the greatest opportunity to reduce these emissions. The IPCC 4th Assessment Report estimates that globally 35% to 40% of all energy-related CO2 emissions (relative to a growing baseline) result from energy use in buildings. Emissions reductions from a combination of energy efficiency and conservation (using less energy) in buildings have the potential to cut emissions as much as all other energy-using sectors combined. This is especially the case for China, India and other developing countries that are expected to account for 80% or more of growth in building energy use worldwide over the coming decades. In short, buildings constitute the largest opportunity to mitigate climate change and special attention needs to be devoted to developing countries.
At the same time, the buildings sector has been particularly resistant to achieving this potential. Technology in other sectors has advanced more rapidly than in buildings. In the recent past, automobile companies have made large investments in designing, engineering, and marketing energy efficient and alternative fuel vehicles that reduce greenhouse gas emissions. At the same time, the buildings sector – dependent on millions and millions of decisions by consumers and homeowners – face a large variety of market barriers that cause very substantial underinvestment in energy efficiency.
How can the trajectory of energy use in buildings be changed to reduce the associated CO2 emissions? Is it possible to greatly accelerate this change? The answer to these questions depends on policy, technology, and behavior. Can policies be crafted and implemented to drive the trajectory down? Can the use of existing energy efficiency technologies be increased greatly and new technologies developed and brought to market? And what is the role of behavior in reducing or increasing energy use in buildings?
These are the three overarching issues. The information assembled in this study and the knowledge derived from it needs to be brought to bear on these three questions. And thus we turn to some of the insights from the study, presented in the form of findings and recommendation. Of the many findings that could be presented we have chosen the few that we consider to be particularly important. Others reading this report would undoubtedly choose a different set. The reader is encouraged to do so.