The AiCARR Guidelines "Energy Efficiency in Historic Buildings" (February 2014) provide information to evaluate and improve the energy performance of historic buildings, fully respecting their significance and expression; where applicable these Guidelines will include the most recent legislation on the subject existing in Italy. These guidelines are intended for both design engineers and superintendencies. They provide the design engineers with a tool for the energy audit of the historic building and offer a framework for the design of possible energy upgrades, which are conceptually similar to that provided for non-protected buildings, but appropriately tailored to the needs and peculiarities of the cultural heritage. On the other hand, these Guidelines provide the institutions responsible for protecting the building, the possibility to objectively decide on the level of energy efficiency achieved as a result of the rehabilitation in accordance with the conservation criteria. (C) 2014 Elsevier B.V. All rights reserved.