Many governments worldwide are setting more stringent targets for reductions in energy use in government/public buildings. Buildings constructed more than 10 years ago account for a major share of energy used by the building stock. However, the funding and "know-how" (applied knowledge) available for owner-directed energy retrofit projects has not kept pace with new requirements. With typical retrofit projects, reduction of energy use varies between 10% and 20%, while experience from executed projects around the globe shows that energy-use reduction can exceed 50%, and renovated buildings can cost-effectively achieve the passive-house standard or even approach net zero energy status (Hermelink and Muller, 2010; NBI 2014; R1CS 2013; GreenBuildingAdvisor.com 2013; Shonder and Nasseri 2015; Miller and Higgins 2015; Emmerich et al. 2011). Previous research conducted under the International Energy Agency's Energy in Buildings and Communities Program (IEA EBC) Annex 46 identified and analyzed more than 400 energy-efficiency measures that can be used when buildings are retrofitted. Measures include those related to the building envelope, mechanical and lighting systems, energy generation and distribution, and internal processes. Implementation of some individual measures (such as building envelope insulation, improved airtightness, and cogeneration) can significantly reduce building heating and cooling loads or minimize of energy waste, but require significant investments with long paybacks. However, when a limited number of core technologies are implemented together, or bundled, they can significantly reduce energy use for a smaller investment, thereby providing a faster payback. In some countries, energy savings performance contracts (ESPC) have proven to be an effective tool for implementing energy retrofit projects. Nevertheless, in many countries the number of projects funded by ESPCs still do not form a significant part of the total investment budgeted by public institutions for energy retrofits. This paper presents the concept and several case studies that illustrate mechanisms that will increase the acceptance of deep energy retrofit (DER) and broaden acceptance of its implementation using ESPCs for a comprehensive refurbishment of existing buildings.