AttiCat Insulation: Owens Corning Blown-In System Review

Topping up a thin attic is the single highest-return energy upgrade in most American houses — the Department of Energy pegs attic air-sealing and insulation paybacks at just a few years — yet homeowners put it off because professional quotes start around $1,500. AttiCat insulation is Owens Corning’s answer: a pink expanding blown-in fiberglass sold by the bag at Home Depot and Lowe’s, paired with a purpose-built rental machine that both stores lend free when you buy enough bags. Two people can blow R-30 over a 1,000 square-foot attic in an afternoon for $600 to $800 in materials. Here’s how the system works, what it really costs, and where it falls short of a pro job.

What AttiCat Is and How the System Works

AttiCat Expanding Blown-In Insulation is loose-fill fiberglass — the same pink glass fiber as Owens Corning batts, chopped and compressed into 27-pound plastic-wrapped bags. The companion AttiCat machine is the clever part: you feed whole bags into its hopper, internal paddles shred and condition the compressed fiber, and a blower fluffs it to full loft and drives it down 100-plus feet of corrugated hose to the attic. The fiber expands dramatically as it’s conditioned, and because everything happens inside the closed machine, dust stays manageable compared with older open-hopper blowers.

The workflow needs two people: one feeding the hopper at the truck or garage, one in the attic directing the hose. A remote cord (or simply shouting down the hatch) lets the attic person stop the feed while repositioning. Coverage math is printed on every bag: for R-30, one bag covers about 27 square feet at roughly 10.25 inches deep; for R-49 — the DOE recommendation for most northern climate zones — figure a bag per 16 or so square feet at about 17 inches. A 1,000 square-foot attic going from bare to R-49 takes roughly 60 bags; topping up an existing R-11 to R-49 takes proportionally fewer.

Real-World Costs

Bags retail for $38 to $45 in 2026. Budget for the common scenarios on a 1,000 square-foot attic:

• Top-up to add R-19 (existing insulation decent): ~25 bags, $950-$1,100 — often less, around $600-$700, if adding over higher existing levels
• Add R-30 over thin existing: ~37 bags, $1,400-$1,650
• Bare attic to R-49: ~60 bags, $2,300-$2,700

The blower rental is free with a minimum purchase — typically 10 bags at Home Depot, with a 4-hour or 24-hour window depending on the store — otherwise about $70-$100 per day. Add $50 to $100 in supporting supplies: attic rulers (cardboard depth gauges, often included free), an insulation dam for the hatch, soffit baffles at $2-$4 each, a respirator, and canned foam for air sealing. Professional blown-in installation runs $1.50 to $3.00 per square foot to reach R-49, so the DIY savings on a typical attic is $800 to $2,000. Note that smaller top-ups flip the math: by the time you rent a machine for a 300 square-foot bonus-room attic, a pro’s minimum charge isn’t far off.

Performance: R-Value, Settling, and Coverage Quality

Blown fiberglass delivers about R-2.5 to R-2.8 per inch at attic loose-fill density — lower per inch than cellulose (R-3.2-3.7), which is why AttiCat depths look tall. The offsetting virtues: the fiber is inorganic, so it won’t rot, feed mold, or attract insects; it’s naturally noncombustible with no added fire retardants; and Owens Corning rates it as virtually non-settling, a claim borne out in practice — fiberglass loft holds within a few percent over decades, whereas cellulose settles roughly 15 to 20 percent and must be over-blown to compensate.

Coverage quality depends entirely on the operator. Work from the eaves toward the hatch in even passes, keep the hose low and moving, and check depth constantly against rulers stationed around the attic. The classic DIY mistakes: piling deep near the hatch while starving the far corners, blowing insulation into soffit vents (install baffles first — blocked soffits cause winter ice dams and summer roasted shingles), and burying recessed lights that aren’t IC-rated (build dams around non-IC cans, or better, replace them with sealed IC-rated LED retrofits before insulating).

The Step Everyone Skips: Air Sealing First

Insulation slows conduction; it does almost nothing to stop warm air leaking into the attic through gaps — and those leaks are often the bigger energy loser. Before the first bag goes in the hopper, spend half a day in the empty (or raked-back) attic with canned foam and caulk: seal around plumbing stacks, wire penetrations, the chimney chase (use metal flashing and fire-rated sealant there, never foam), top plates of interior walls, bath fan housings, and the attic hatch itself (weatherstrip it and glue foam board to its back). This is miserable, unglamorous work, and it roughly doubles the benefit of the insulation going on top.

Ventilation is the other precondition. Confirm soffit and ridge or gable vents are open and baffled so the attic can breathe above the new blanket. A tight ceiling with a well-vented attic above R-49 fluff is the recipe that keeps northern attics frost-free and southern attics from cooking the HVAC ducts.

AttiCat vs Cellulose vs Batts vs Pro Install

Against blown cellulose (the Lowe’s Greenfiber machine route): cellulose costs less per delivered R — often 25 to 40 percent cheaper for the same R-49 — and blocks air movement a bit better at its higher density. Fiberglass counters with no settling, no dust storm during install, lighter weight on the drywall, and better tolerance of incidental moisture (wet cellulose mats and holds water; glass dries). Both are legitimate; crews and homeowners split largely on availability and preference.

Against laying fiberglass batts across the joists: blown-in wins decisively on coverage, flowing around trusses, wires, and irregular bays where batt layups leave a lattice of gaps. Batts only make sense in small, accessible rectangles. Against hiring a pro: the pro brings a truck-mounted blower (faster, better conditioning), does the air sealing if you pay for it, and carries the ladder-and-liability risk. If your attic has knob-and-tube wiring, vermiculite (possible asbestos — test before disturbing), or barely any headroom, stop and call professionals. For a straightforward open attic, AttiCat is genuinely DIY-achievable in a day.

Installation Day: A Realistic Run-Through

Pick a mild day — attics over 100°F end projects early. Suit up in long sleeves, gloves, goggles, and an N95 or better. Stage the machine in the driveway or garage, run the hose up through the hatch, and have your feeder load bags at a steady rhythm; the machine processes a bag every couple of minutes at full pace. In the attic, work backward from the farthest corner toward the hatch so you never trap yourself, keep weight on joists or a kneeling board (one foot through the drywall erases the project’s savings instantly), and sweep the hose side to side in overlapping passes, building depth evenly rather than in dunes.

Expect the whole event — pickup, prep, blowing 40 bags, cleanup, return — to fill 6 to 8 hours for two people. Mark your final depth on a rafter with the date and target R-value; the next owner’s energy auditor will thank you.

How Much R-Value Should You Target?

Match depth to your climate zone rather than guessing. The DOE and 2021 IECC point most of the country toward R-49 to R-60 attics: southern zones 1-2 can stop at R-49, the broad middle of the country belongs at R-49 to R-60, and cold-climate zones 5-8 justify R-60 where framing depth allows. Existing insulation counts toward the total — measure its depth, figure R-2.5 to 3 per inch for old fluff, and buy bags for the difference. The 25C federal tax credit returns 30 percent of material costs up to $1,200, and utility rebates of $0.10 to $0.50 per square foot are common; both apply to DIY materials, so keep the receipts.

Verdict: Who Should Use AttiCat

AttiCat insulation is one of the rare big-box systems that delivers on its promise: pro-grade blown fiberglass, a genuinely usable free-rental machine, and transparent per-bag coverage math. For a homeowner with a helper, an open accessible attic, and a weekend, taking a house from R-11 to R-49 for roughly $1,000 to $1,500 in materials is an outstanding investment — typically returning its cost in energy savings within 2 to 4 heating seasons in cold climates. Do the air sealing first, baffle the soffits, respect the depth rulers, and the pink stuff will quietly pay you back every month for the life of the house.