While historic buildings possess much embodied energy and quality building materials, there is no arguing that many of these buildings lack energy efficient HVAC systems. In a country that is growing increasingly aware of the need for sustainable building practices, it is important for the preservation community to both protect and retrofit the historic building stock.

The National Park Service has published two briefs that discuss HVAC and energy efficiency in historic buildings: Conserving Energy in Historic Buildings (brief 3) and Heating, Ventilating, and Cooling Historic Buildings: Problems and Recommended Approaches (brief 24).