The Illustrated Guidelines on Sustainability for Rehabilitating Historic Buildings replaces the chapter on "Energy Conservation" in the Illustrated Guidelines for Rehabilitating Historic Buildings published in 1992. (This same guidance is presented in the chapter entitled "Energy Retrofitting" in the unillustrated Guidelines for Rehabilitating Historic Buildings.) The illustrated version of the Guidelines for Rehabilitating Historic Buildings was designed to further enhance overall understanding and interpretation of basic preservation principles. The Illustrated
Guidelines on Sustainability begin with an overview focusing on the fact that historic buildings are themselves often inherently sustainable and that this should be used to advantage in any proposal to upgrade them. These guidelines offer specific guidance on how to make historic buildings more sustainable in a manner that will preserve their historic character and that will meet The Secretary of the Interior's Standards for Rehabilitation. The written guidance is illustrated with examples of appropriate or "recommended" treatments and some that are “not recommended” or could negatively impact the building’s historic character. The National Park Service Branch of Technical Preservation Services has developed these illustrated guidelines in accordance with its directive to provide information concerning professional methods and techniques to ensure the preservation and rehabilitation of the historic properties that are an important part of the nation’s heritage.