Conditioned Attic Space

A design decision to have a central ducted heating and cooling system with ducts and air handler located in the attic is another good reason to insulate and air seal at the roof line which will provide a conditioned or semi conditioned space for the hvac equipment.

Conditioned attic space.

Traditionally building codes have required attic ventilation. The loss of energy efficiency means some designers choose to move the ductwork into the conditioned areas of the home and leave the attics unvented. If the home has any mechanicals in the attic like hvac or duct work the unvented attic system will keep it protected. This system can help you avoid condensation in the attic.

A fundamental requirement of an unvented attic assembly is the use of air impermeable insulation on the underside of the unvented roof to prevent air infiltration and exclude airborne moisture from the attic. The intended purpose was to allow warm air and moisture to escape. The attic space becomes indirectly conditioned as a result of the air leakage heat transfer and vapor diffusion through the ceiling. Building america research has demonstrated unvented conditioned attics can substantially improve energy performance while allowing home builders to continue locating hvac systems in the attic space.