Fig. 3: Integrated technical building energy-saving potential of a typical medium office building in the United States.

We broke down the building energy saving into four key categories α1–α4 are the saving potentials (%). E0–E4 represent different gross site energy use intensity (EUI). E0 represents the median of US office buildings34; E4 is the median of zero energy verified building in the US35. The selected climate zones (CZs) represent the top four regions (Honolulu: CZ 1A, Baltimore: CZ 4A, Buffalo: CZ 5A, and Los Angeles: CZ 3B) defined by the International Energy Conservation Code (IECC) based on a number of office buildings from CBECS 2012 data34,59.