When you install insulation in an existing, closed wall or in an attic, it likely will be a loose product called blown-in cellulose insulation. With an attic, this type of insulation is just one option along with the other popular alternative, fiberglass batts or blown-in fiberglass. But with closed walls, blowing in loose-fill cellulose insulation is still, by far, the most practical and cost-effective method.
What Is Loose Fill Blown Cellulose Insulation?
Cellulose insulation is a type of wood- or paper-based product. It insulates empty spaces in the structural part of a house to slow down the transmission of heat or cold. Cellulose insulation is thick, dense, and clumpy, with a consistency much like down feathers. The chief value of this shape and size is that the insulation can fit in enclosed areas (such as walls) and can conform around obstructions such as wires and ducts (found both in walls and in attics).
Cellulose insulation technically can come from any cellular plant source, such as corncobs or sisal. But generally, it is derived from wood, and more specifically from paper: recycled newspapers, cardboard, office paper, and other common waste paper products. For this reason, cellulose insulation is considered an eco-friendly home product.
Cellulose Insulation Benefits
The thermal performance of loose filled cellulose compares favorably to other types of low cost insulation, but is lower than that of polyurethane and polyisocyanurate foams.
Long-Term Cost Savings
Annual savings from insulating vary widely and depend on several factors, including insulation thickness, original wall performance, local climate, heating/cooling use, airtightness of other building elements and so on.
Insulation reduces sound traveling through walls and between floor levels. Cellulose provides mass and damping. This reduces noise in 2 ways, it reduces the lateral movement of sheetrock and attenuates the passage of sound along cavities.
Mold and Pest Control
The borates in cellulose insulation provide added control against mold. Installations have shown that even several months of water saturation and improper installation did not result in mold.
The borate treatment also gives cellulose the highest (Class I) fire safety rating. Many cellulose companies use a blend of ammonium sulfate and borate.
A vapor barrier may not be needed with cellulose insulation. Cellulose acts to distribute moisture throughout the cavity, preventing the buildup of moisture in one area and helping to dry the moisture more quickly.