Unvented Attic Space

An unvented attics is one where the air vapor and thermal controls are installed at the roof deck.

Unvented attic space.

However they require different approaches in different climate locations. Making the attic a conditioned space means the space will be the same temperature as the rest of your home. The unvented attic space is completely contained within the building thermal envelope 2. This system can help you avoid.

The entire attic becomes conditioned space eliminating drafts and temperature fluctuations. In hot climates unvented attics are ideal where hvac equipment and ductwork are located in the attic. Modifying the attic to create an indirectly conditioned attic space with icynene can significantly reduce energy consumption. Air does not flow into the soffits and does not flow out of ridge or gable vents.

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. Unvented attic roof designs have the advantage of providing conditioned spaces for ductwork and air handlers. The unvented attic space is completely contained within the building thermal envelope. Adding unvented attic insulation like spray foam seals the building envelope and stops airflow.

The unvented attic space is completely within the building thermal envelope. The energy savings touted by unvented attics can be as high as 20. However if moisture is able to enter the unvented attic space it may lead to roofing panel issues. The unvented attic is indirectly conditioned space since heat and moisture transfer occurs through the top floor ceiling particularly if the ceiling is not airtight.

In cold climates attic ventilation is a common method to remove humid air. There are typically no supply or return registers from the hvac system specifically located in an unvented attic space. No interior class i vapor retarders are installed on the ceiling side attic floor of the unvented attic assembly or on the ceiling side of the unvented enclosed rafter assembly. No interior vapor retarders are installed on the ceiling side attic floor of the unvented attic assembly 2009 irc.

Unventilated attics can help to mitigate energy loss through leaky ducts or ceiling fittings.