Attic Space Vs Plemum Space

The energy savings touted by unvented attics can be as high as 20.

Attic space vs plemum space.

I wonder if the nec definition of the word plenum would actually apply to the entire attic space. However i have two questions if i want to centrally air condition my entire house. That dead air space is designed to be a buffer between the roof. However if moisture is able to enter the unvented attic space it may lead to roofing panel issues.

Space between the structural ceiling and the dropped ceiling or under a raised floor is typically considered plenum. It s easy to see your point about eliminating ductwork from the attic. Compare that with the daily 140 degree temperatures found in vented attics. A basement is below and an attic is above the main part of the house.

This allows intensive cooling to be pumped through the space under the floor to cool the servers switches routers etc. Unventilated attics can help to mitigate energy loss through leaky ducts or ceiling fittings. A plenum space is a part of a building that can facilitate air circulation for heating and air conditioning systems by providing pathways for either heated conditioned or return airflows usually at greater than atmospheric pressure. The velocity of the overall air movement within the two spaces would be substantially different at the same cfm.

This by definition is a plenum air space and requires plenum rated cable. However some drop ceiling designs create a. That space typically has about a 10 12 degree difference than the conditioned space below it. Think about the volume of space normally associated with return air ducts vs the volume of space involved in an attic space.

Cabling between the many devices and to the users runs through this open floor space. Don t use the foamed attic space as a conditioned plenum. Plenum trusses create a reverse bulkhead in the center of the attic space where ducting can be housed in an insulated area. A two room addition on the 1st floor has limited attic space and a 4 crawl space.

The plenum truss bulkhead adds only the amount of inside conditioned space required to house the ductwork by modifying the roof framing to create a boxed in area in the otherwise unconditioned attic.