What to Use Instead of Fiberglass Duct Rigid Foam Board

Loose-Fill Insulation

• Created from a number of different materials, including fiberglass, recycled newsprint and cellulose, loose-fill insulation comes in small pieces that fill in the spaces between walls and around ductwork. Since loose-fill insulation comes in non-uniform pieces, however, these pieces do not fit perfectly together, which does leave some spaces within the wall and around the ductwork. This may allow some air to pass through, which decreases the effectiveness of the insulation. Over time, however, the insulation settles, which creates space at the top of the area and allows for the addition of extra insulation.

Batting

• Similar to fiberglass rigid foam boards, fiberglass batting comes in sheets that hold together inside the wall or around ductwork. This adhesion of the insulation prevents gapping throughout the insulation, which can help create better coverage than loose-fill insulation. Unlike fiberglass rigid foam boards, though, fiberglass batting has a blanket-like flexibility, making it easy to wrap around circular ducts or fit through small spaces if necessary for application.

Foam Insulation

• Foam insulation consists of a liquid substance that turns into foam when sprayed. As the foam settles, it continues to expand, which allows it to fill in every empty space between walls or around ductwork. Foam generally provides the most overall coverage in an area, whether sprayed between walls or around a duct. One downside to foam insulation, however, is that it contains chemicals that aren’t environmentally friendly, though some vegetable-based foam insulations provide a more environmentally friendly option than standard foams.

Insulation Installation

• The process of installing insulation depends upon the type of insulation you choose to install. Fiberglass duct rigid foam board and fiberglass batting generally must be installed prior to putting in the interior wall. The pieces line the wall between the studs. The process of installing foam insulation and loose-fill insulation, on the other hand, consists of spraying the insulation through a hole in a wall with a hose-like apparatus to fill each cavity between studs.