ASHRAE/IES Standard 100 provides criteria for reduced energy consumption through improved energy efficiency and performance in existing buildings.Among changes to the 2018 edition of the standard are the following:Updated Purpose to more clearly state the goal of the standard. Addition of normative primary energy EUI target tables in Sections 7 and 10 and in Normative Annex A, and a primary energy EUI calculation option in Annex A, to add an alternative compliance path for the qualified person seeking compliance with the standard Clarification of energy audit requirements for buildings without energy targets by qualifying when a Level 1 audit can be used to comply with the standard Addition of new Informative Annex M to provide guidance on selecting the appropriate building type