An unvented conditioned attic is a sealed, insulated space where the thermal and air barriers are aligned with the roof deck instead of the ceiling, bringing the attic within the home’s conditioned envelope.

This design can reduce moisture risks, provide additional space utilization for occupants, and protect mechanical systems from temperature extremes. This conditioned space also supports safety, especially in wildfire-prone areas where ember intrusion through vents is a concern.

This guide provides information and details on designing and installing an unvented conditioned attic.