In many cities, buildings are responsible for a majority of the city’s overall carbon emissions. For this reason, low-carbon buildings will be an essential component for the development of sustainable cities. Effectively reducing building emissions will require a combination of advancements in low-carbon energy systems technology and initiatives to reduce building-related energy use in both new and existing buildings. A building’s energy use is also a function of the operations-related management practices and the behavior of the people who use the building and it is estimated that about half of the world’s building stock in 2050 will consist of buildings that already exist today. Subsequently, improving the energy use patterns of existing infrastructure has the potential to play a major role in the advancement of low-carbon buildings.