Same family of material (cellulose), different method. Dense pack uses controlled pressure to fill enclosed cavities evenly, while attic blown-in is laid on open attic floors.

Any loose-fill material can settle if installed incorrectly. A proper dense-pack install is done to a target fill method so cavities are packed consistently.

It often helps, especially compared to empty cavities, because denser fills reduce sound transmission through walls.

Yes, especially for older homes with under-insulated walls. Improving wall insulation is one of the most noticeable comfort upgrades during cold snaps.

Loose-fill cellulose is usually blown open into an attic floor to quickly build depth (great for attics). Dense-pack cellulose is blown under higher pressure into closed cavities (like finished walls) so it packs tight, fills voids, and resists settling in vertical spaces, making it the go-to for walls.

Loose-fill can settle in wall cavities over time if it isn’t installed to dense-pack standards. For wall retrofits, installers target a dense-pack installation density so the material stays in place and performs consistently.

Most dense-pack cellulose is treated with borate/boric acid compounds that help it perform better in real homes: improved fire resistance (helps resist flame + smoldering) and added pest deterrent benefits because borates are commonly used for insect/fungal control in building materials.

• R-value per inch: Cellulose is commonly around R-3.2 to R-3.8 per inch (product + install quality matter).

• Air sealing: Dense-pack can significantly reduce air movement inside wall cavities when installed to proper density.

• Moisture: It should not be installed over active leaks; manage bulk water and humidity first. 

• Settling: Proper dense-pack density is designed to resist settling in walls.