Many existing commercial buildings that were retrofitted with integrative design principles in mind have achieved a physical energy use intensity (EUI) close to or below 30 kBTU/sf-y. These significant savings have been realized across a wide range of climate zones.
The Reinventing Fire analysis developed its integrative design estimates by taking the average of the difference between the performed EUI in these cases and the AEO 2010 baseline.
U.S. Energy Information Administration. 2010. Annual Energy Outlook 2010. Washington DC: U.S. Energy Information Administration, May 11. link