The preference for a large segment of the U.S. housing industry has been to locate HVAC systems in unconditioned attics, but this is highly inefficient. The additional heat loss and gain of ducts in unconditioned, vented attics increases energy use for heating and cooling by 10%. Additionally, duct air leakage has been measured to commonly exceed 20% of conditioned air flow, which results in a significant energy loss when ducts are in unconditioned space.

This Top Innovation award demonstrates Building America research from Building Science Corporation that proves that unvented, conditioned attics can substantially improve energy performance while allowing home builders to continue locating HVAC systems in the attic space. In addition to influencing builders across the country to adopt unvented, conditioned attics, Building America research has helped influence code acceptance of this innovation since 2006. Read about this Top Innovation.

See an example of this Top Innovation in action. Find case studies of Building America projects across the country that demonstrate unvented, conditioned attics.

View other Top Innovations in the Advanced Technologies and Practices category.