Buildings account for 28% of global energy-related greenhouse gas emissions. In large cities, the share is even greater: emissions from buildings in London, Tokyo and New York respectively account for 76%, 71% and 67% of total emissions. Moreover, global energy-related emissions from the building sector increased by 25% over the 2000-2017 period and the energy intensity in buildings must be reduced by 30% by 2030 to align with the Paris Agreement.

Improving energy efficiency in buildings can substantially reduce energy consumption and CO₂ emissions, while also stimulating job creation and making energy more affordable for households. In the EU, for example, two-thirds of residential buildings were built before 1980 and a quarter were built before 1945. Such buildings tend to perform poorly, in terms of energy efficiency, and represent a unique opportunity to drastically reduce energy consumption. Investment in energy efficiency in buildings provides several additional benefits such as job creation, health improvements, and reduced energy expenditure, which would significantly contribute to a green recovery from COVID-19.

Given the local nature of buildings and related policy environments, cities and regions are key actors to champion energy efficiency in buildings. They have a unique ability to pilot innovative approaches and technologies, to factor in context-specific local elements, and to leverage their authority on building regulations and public procurement. Cities and regions around the world are assuming a strong leadership role, often adopting more ambitious building regulations than the national government, and are working to overcome barriers to the implementation of energy efficiency measures.