In the design process few decisions have as many long-term implications for the performance and durability of a building as the choice of insulation. For the designer, builder and owner, insulation can and should play a multifaceted role that extends far beyond those noticeable or expected benefits, such as energy savings, comfort and enhanced indoor air quality. Insulation, in combination with good detailing and quality control, can play a preventive role by minimizing the chances that things could go wrong.