Plenum Boxes insulated with Duct Liner for Residential

A plenum box fits over the inside unit and is the first stage of the air supply. Holes, usually 2, are cut out of the box. These holes, typically 12” or 14” diameter round are cut out by the HVAC contractor during the install. A round Airtite takeoff is typically used over the hole; either Snaplock pipe or Flex Duct attaches to the Airtite takeoff. It will then reduce down to the size diameter needed for the air balance load. (start off big and reducing down). From there, the air goes out thru the attic or crawl space and distributed thru each rooms supply registers/grilles.

Codes for the thickness of insulation vary per state and per county. In Memphis, codes specify 1/2” Liner. When it comes to 1/2” Fiberglass Liner, it’s a challenge for a Rotary Liner to retain it’s consistency and that’s where JM’s RC Product stands out. Only in the RC will you find a 1/2” Liner that’s stiff, holds it’s shapes after being cut for a clean look; contractors prefer it because it doesn’t fray like other Fiberglass duct liners. This is important not only for ease of cutting but also because fraying means that there’s likelihood of fibers getting in the airstream.