TL;DR
Blown-in cellulose is loose-fill insulation made from shredded recycled newspaper treated with borate fire retardants, machine-blown into attics and wall cavities at roughly R-3.2 to R-3.8 per inch. It packs around wiring and irregular framing better than batts, and its density resists the convective looping that degrades loose fiberglass in cold attics; dense-packed in walls it also slows air leakage.
What it means
Blown-in cellulose is loose-fill insulation made from shredded recycled newspaper treated with borate fire retardants, machine-blown into attics and wall cavities at roughly R-3.2 to R-3.8 per inch. It packs around wiring and irregular framing better than batts, and its density resists the convective looping that degrades loose fiberglass in cold attics; dense-packed in walls it also slows air leakage. The borates double as pest and mold inhibitors. Settled thickness, about 15 to 20 percent below the installed fluff in open attics, is accounted for on the coverage chart, and bids should state the settled R-value with bag counts per the federal R-value rule.
Where it sits in the glossary
Blown-in cellulose is part of the Trade jargon group inside the ProFix Directory glossary. Browse every term in this category from the glossary index.
Why Ohio homeowners should know it
This is a term Ohio homeowners encounter when reading contractor quotes, hiring paperwork, or inspection reports. Understanding it well enough to ask one good follow-up question is usually all the protection a homeowner needs.
ProFix Directory keeps definitions short on the index page and saves the longer context — Ohio-specific rules, where the term comes from, and which ProFix tools touch it — for these per-term pages so the term is easy to cite and easy to share.
ProFix tools that touch this term
See also
License: CC-BY-4.0 — quote freely with attribution to ProFix Editorial Team / ProFix Directory.