Blown-In Insulation Calculator: Home Depot vs Lowe's vs Owens Corning
Blower rental terms, bag minimums, brand availability, price per bag, and return policy — side by side. Which retailer to buy from depends on your material choice, not just your ZIP code.
Quick Answer
For cellulose insulation, both Home Depot and Lowe's offer a free 24-hour blower rental with 20 or more bags of GreenFiber per Home Depot Tool Rental policy — choose on local price. For Owens Corning AttiCat fiberglass, Home Depot is the only big-box option per the Owens Corning AttiCat Product Data Sheet + Home Depot tool-rental program — AttiCat requires the OC expanding-bagger blower, which is not available at Lowe's (this guide treats AttiCat as HD-only; any Owens Corning fiberglass at Lowe's is a different SKU, not AttiCat-system compatible). GreenFiber Sanctuary cellulose runs approximately $13–$22 per 25-lb bag; AttiCat runs approximately $35–$50 per 27.5-lb bag (@asOf 2026-Q2 — verify before purchasing). Use the blown-in R-value calculator to compute estimated bag counts before heading to the store.
Quick decision: which retailer?
- Want AttiCat fiberglass (no settling, dry attics) → Home Depot only — requires OC expanding-bagger blower
- Want lowest material cost at same R-value → cellulose at whichever local store is cheaper; both offer free blower with ≥20 bags
- Already have Lowe's store credit / gift cards → cellulose (GreenFiber INS515LD or Sanctuary) at Lowe's works fine
Blower Rental Terms: Home Depot vs Lowe's
Because both retailers offer free blowers with bag minimums, the AttiCat vs cellulose choice usually determines your store — not the other way around. The critical difference: AttiCat requires the OC expanding-bagger blower (Home Depot only), while cellulose works with either retailer's standard machine.
| Factor | Home Depot | Lowe's |
|---|---|---|
| Cellulose blower (standard) | Free 24h with ≥20 bags cellulose | Free 24h with ≥20 bags cellulose |
| AttiCat expanding-bagger blower | Free or low cost with ≥10–20 AttiCat bags | Not available — AttiCat system is HD-exclusive |
| Blower rental without minimum | ~$75–$100/day (standard rental rate) | ~$75–$100/day (standard rental rate) |
| Deposit / hold | ~$50–$250 credit card hold | ~$50–$250 credit card hold |
| Rental period | 24 hours; extend at daily rate | 24 hours; extend at daily rate |
| Blower cross-compatibility | Cellulose blower ≠ AttiCat blower | Cellulose blower only; no AttiCat machine |
| Return policy (insulation bags) | 90 days, unopened with receipt | 90 days, unopened with receipt |
Terms and deposits vary by store; confirm before purchasing.
How the bag count + cost math works
Bags needed = ceil(Attic area sq ft / Coverage sq ft per bag at target R)
Add 10% buffer = ceil(Bags needed × 1.10)
Cost per sq ft = Price per bag / Coverage sq ft per bag at target R
Example (R-30, 1,000 sq ft): GreenFiber Sanctuary 25 lb: 1000 / 27.4 = 36.5 → 37 bags × $15 = $555 → $0.55/sq ft
Example (R-30, 1,000 sq ft): AttiCat 27.5 lb: 1000 / 34.5 = 29 bags × $43 = $1,247 → $1.25/sq ft
Source: Coverage rates from OC L77 fact sheet (AttiCat) and GreenFiber INS515LD product guide (Lowe's PDF). Prices sampled from national Home Depot / Lowe's listings @asOf 2026-Q2 — verify before purchasing. FTC R-Value Rule 16 CFR Part 460 requires coverage charts use settled thickness.
The AttiCat Blower Exclusivity Rule — Why Your Material Choice Picks Your Retailer
The most important retailer choice is AttiCat blown fiberglass vs cellulose. AttiCat locks you into Home Depot — the OC expanding-bagger blower is not available at Lowe's rental; a standard cellulose blower won't properly expand AttiCat bags (clumped, uneven coverage). Lowe's may stock generic OC loose-fill fiberglass (non-AttiCat) compatible with standard blowers; the AttiCat expanding-bag system specifically is HD-only.
The AttiCat blower expands compressed fiberglass approximately 3× through the OC machine. The minimum for the free AttiCat blower is typically 10–20 bags depending on store. Per the FTC R-Value Rule (16 CFR Part 460) ↗, all insulation coverage charts must use settled thickness — AttiCat fiberglass does not settle, so its charts reflect final installed depth. For most R-49 attics at 1,000 sq ft (~53 bags with buffer), you'll exceed the blower minimum either way.
Rental Terms in Practice: The Bag-Minimum Cliff
Bag-minimum cliff: if you buy 20 bags for the free blower and return 5 after your project, some stores deduct the standard blower rental ($75–$100 per 24 hr) from your refund. This is manager-discretion and not in either retailer's online policy.
The practical rule: Estimate your bag count precisely before purchasing, add 10% buffer, then confirm your final bag count stays well above the free-blower minimum. Use the blown-in R-value calculator for an estimated count at your target R-value. A small buffer above the minimum prevents the cliff entirely.
Private-Label Cellulose: Arctic Fiber (Lowe's) vs Northern Fiber (HD)
Both retailers have carried private-label cellulose at lower price points than GreenFiber Sanctuary: Lowe's has stocked Arctic Fiber (25 lb, ~46 sq ft/bag at R-19) and Home Depot has carried Northern Fiber (25 lb, SKU 289148). Availability varies by region. Per the FTC R-Value Rule (16 CFR Part 460) ↗, all products must display coverage charts at settled depth — compare sq ft per bag at your target R before deciding on per-bag price. Exact prices for private-label brands were not verified from primary pages — confirm in store.
Blown-In Insulation: Brand vs Retailer Comparison
The table below maps major blown-in products to their primary retailer and key purchasing factors. GreenFiber Sanctuary is at both retailers; AttiCat is Home Depot-exclusive.
| Brand / Product | Bag weight | Home Depot | Lowe's | Blower minimum | Return window |
|---|---|---|---|---|---|
| GreenFiber Sanctuary (cellulose) | 25 lb | ~$13–$18/bag | ~$15–$22/bag | ≥20 bags (either retailer) | 90 days, unopened |
| GreenFiber INS515LD (cellulose) | 30 lb | Available | Available | ≥20 bags | 90 days, unopened |
| Owens Corning AttiCat (fiberglass) | 27.5 lb | ~$35–$50/bag | Primarily HD; confirm in store | ≥10–20 bags (HD; AttiCat blower) | 90 days, unopened |
| Arctic Fiber (cellulose, private-label) | 25 lb | Not typically carried | Price varies — verify in store | ≥20 bags (confirm locally) | 90 days, unopened |
| Northern Fiber (cellulose, private-label) | 25 lb | Price varies — verify in store (SKU 289148) | Not typically carried | ≥20 bags (confirm locally) | 90 days, unopened |
Sources: OC L77 AttiCat fact sheet (@asOf 2019-Q4); GreenFiber INS515LD product guide via lowes.com PDF (@asOf 2016-Q4); Perplexity synthesis of current retailer Q&A pages and product listings (@asOf 2026-Q2). AttiCat prices corroborated by competitive-analysis.md Phase 1-B research pack. Private-label prices not verified from primary pages — confirm in store. All prices approximate.
For a full brand-level comparison at every R-value target (R-30 through R-60) including GreenFiber INS515LD and INS541LD bag counts, see our cellulose insulation calculator guide (GreenFiber INS515LD: ~31 bags/1,000 sq ft at R-30; ~57 bags at R-49). For the AttiCat-specific L77 coverage chart and depth comparison at R-19/R-30/R-49, see the AttiCat blown-in insulation guide (~29 bags at R-30; ~48 bags at R-49 per 1,000 sq ft).
Cellulose vs Fiberglass — Retailer Decision Matrix
Matrix below frames the cellulose vs fiberglass call by retailer-context factors — not by R-value performance (both perform similarly at the same installed R).
| Factor | Cellulose (GreenFiber) | Fiberglass (AttiCat) |
|---|---|---|
| Retailer options | Home Depot OR Lowe's | Home Depot only (for AttiCat system) |
| Blower type required | Standard cellulose blower (both retailers) | OC expanding-bagger blower (HD only) |
| Free blower minimum | ≥20 bags (both retailers) | ≥10–20 bags (HD; varies by store) |
| Approx. $/bag (2026-Q2) | ~$13–$22 (25–30 lb) | ~$35–$50 (27.5 lb) |
| Approx. $/sq ft at R-30 | ~$0.40–$0.65/sq ft | ~$1.00–$1.45/sq ft |
| Depth at R-49 | ~13.2 in (cellulose: ~3.3 R/in) | ~16.25 in (fiberglass: ~2.79–3.0 R/in) |
| Settling (first 1–2 years) | 18–20% thickness reduction (per ASTM C739) | Negligible — no overfill buffer needed |
| Moisture performance | Borate-treated; may absorb moisture if chronic leak | Fiberglass does not absorb moisture |
At R-30 over 1,000 sq ft, cellulose runs approximately $550–$700 in materials while AttiCat runs approximately $1,250–$1,450 in materials. Cellulose settles 15–20% per ENERGY STAR installation guidance and ASTM C739; the coverage chart already accounts for settled depth, but you must install to the pre-settled depth. For attics with no moisture history in Climate Zones 2–4, cellulose typically delivers better cost-per-R-value.
Cost Estimate: Blown-In Insulation by Retailer
Estimated material costs for a 1,000 sq ft bare attic at R-38 and R-49 (DIY, labor excluded; blower rental assumed free under the bag-minimum threshold).
| Product | R-38 (bags + 10%) | R-38 est. cost | R-49 (bags + 10%) | R-49 est. cost |
|---|---|---|---|---|
| GreenFiber Sanctuary (25 lb) HD or Lowe's | ~45 bags | ~$600–$990 | ~61 bags | ~$795–$1,340 |
| GreenFiber INS515LD (30 lb) HD or Lowe's | ~45 bags | ~$540–$790 | ~62 bags | ~$745–$1,085 |
| Owens Corning AttiCat (27.5 lb) Home Depot only | ~21 bags | ~$735–$1,050 | ~28 bags | ~$980–$1,400 |
Cost estimates use approximate 2026-Q2 retail price ranges (national spread — coastal metros and AK/HI typically 10–20% higher than interior stores). Actual costs depend on store, promotions, and SKU. GreenFiber Sanctuary $13–$22/bag; INS515LD $12–$18/bag; AttiCat $35–$50/bag. Blower rental free under minimum-bag threshold.
If you already have 3–4 in of insulation — partial-fill bag deltas
Existing 3–4 in (~R-10 to R-13) topping to R-49 for 1,000 sq ft: INS515LD ~46 bags ($550–830), AttiCat ~17 bags ($595–850). Use the blown-in R-value calculator for layered/partial-fill mode.
For Zones 5–8 where the DOE recommends R-60 for uninsulated attics, AttiCat's cost premium versus cellulose grows further. At R-60, GreenFiber INS515LD requires approximately 80 bags/1,000 sq ft (~$960–$1,440) versus AttiCat at approximately 35 bags per the OC TDS R-60 row (20.5 in depth, 31.5 base bags/1,000 sq ft + 10% buffer; verify against the L77 chart printed on your specific bag). For estimated bag counts at your R-target, use the blown-in R-value calculator.
Bag-count variance across CraftedCalcs pages: some examples include the 10% buffer, others quote base rate. The calculator is canonical — it shows base + buffered counts side-by-side.
Climate Zone R-Value Targets and Retailer Implications
Your DOE climate zone determines the R-value target, which in turn drives your bag count and retailer blower-minimum strategy. The following targets are based on the 2021 IECC (N1102.1) and DOE cost-effectiveness analysis via energy.gov; verify the IECC edition enforced in your jurisdiction with your local building department:
| Zone (example cities) | DOE target (uninsulated) | DOE target (existing 3–4 in) | Retailer blower implication |
|---|---|---|---|
| Zone 1 (Miami FL, Honolulu HI) | R-30 | R-25 | ~36–41 bags cellulose; either retailer |
| Zone 2 (Phoenix AZ, Houston TX) | R-49 | R-38 | ~62 bags cellulose or ~28 bags AttiCat at R-49 (10% buffer); easily clears HD's 10-bag and Lowe's 20-bag blower-rental promo thresholds |
| Zone 3 (Atlanta GA, Dallas TX) | R-49 | R-38 | Same as Zone 2; blower promo threshold easily met |
| Zone 4A/4B (DC, St. Louis MO) | R-49–R-60 | R-38–R-49 | Zone 4C marine (Portland OR): R-49–R-60. Vapor retarder: Zone 4A may require Class II per IECC N1102.4 (see DOE guidance at energy.gov; verify with your local building department) |
| Zone 5 (Chicago IL, Denver CO) | R-60 | R-49 | R-60 AttiCat: coverage not in verified TDS — read the "R-60, sq ft per bag" number from your bag's L77 chart, enter it in the calculator's custom-coverage mode for your estimated count. Cellulose alternative: GreenFiber INS515LD ~72 bags at R-60 per 1,000 sq ft. |
| Zones 6–8 (Minneapolis MN, northern AK) | R-60 | R-49 | Cellulose strongly preferred for cost; Class II vapor retarder often required per IECC N1102.4 |
Sub-zone note: Zone 4 is subdivided into 4A (humid), 4B (dry), and 4C (marine). Zone 4A requires Class II vapor retarder in ceiling assemblies per IECC N1102.4 (see DOE guidance at energy.gov); Zone 4B dry typically does not. Portland OR (Zone 4C marine) and Washington DC (Zone 4A) have different retarder requirements despite both being Zone 4. Confirm with your local building authority. DOE zone targets are for 2021 IECC — your jurisdiction may have adopted an earlier or later edition.
Rafter Baffles — Required Before Blowing at Either Retailer
Whether you buy from Home Depot or Lowe's, IRC §R806 (verify locally-adopted edition with your local building department) requires maintaining the free vent area at 1:150 ratio (reducible to 1:300 with Class II vapor retarder on half the ceiling + balanced venting). Before blowing cellulose or fiberglass to depths of 13–20+ inches, install rafter baffles at every eave bay. Without baffles, insulation can migrate into soffit vents, reducing airflow and raising summer attic temperatures 10–20°F — defeating the R-value investment.
Retailer Decision Checklist — Before You Buy
Use this checklist in order; material choice locks in your retailer.
- Find your DOE climate zone — Enter your ZIP at energystar.gov or the DOE zone map at energy.gov. This determines your R-value target.
- Decide material type first: cellulose or fiberglass — If you want AttiCat (fiberglass, no settling, moisture-resistant), you must buy from Home Depot. If you want cellulose (lower $/sq ft, shallower depth profile), either retailer works.
- Calculate estimated bag count — Use the blown-in R-value calculator with your attic area and R-target. Add 10% overage buffer. Confirm your final bag count exceeds the free-blower minimum (typically 20 bags for cellulose; 10–20 for AttiCat at HD).
- Call your specific store and confirm blower availability — Confirm the bag minimum for your specific product SKU, whether the blower is in stock and reserved, and the deposit amount. Terms are not uniformly published online and vary by store and date.
- Compare price per sq ft — not just price per bag — Divide your local store's bag price by the coverage chart's sq ft per bag at your target R. A higher price per bag with better coverage can be cheaper per sq ft.
- Install rafter baffles at every eave bay before blowing — Cardboard or rigid foam baffles extending 12+ inches above planned depth. Required to maintain soffit-vent airflow per IRC §R806 (verify locally-adopted edition with your local building department) .
- Air-seal top plates and penetrations before insulating — Blown insulation fills space but does not air-seal. Low-expansion foam or fire-rated caulk on top plates and around recessed lights recovers 15–30% effective R-value performance.
- Keep all bags sealed until install — Opened bags cannot be returned at either retailer. Only open bags during active blowing to preserve your 90-day return window on unused bags.
Common Blown-In Insulation Retailer Mistakes
Each mistake below can cost $75–$100 in surprise rental fees or several hundred dollars in over-purchased material — all preventable with the checklist above.
- Buying AttiCat bags and trying to use Lowe's cellulose blower — The Owens Corning expanding-bagger blower and the standard cellulose blower are not interchangeable. AttiCat's compressed fiberglass must be expanded by the OC-specific machine; a standard blower produces clumped, uneven coverage with air voids. If you buy AttiCat, you must also use the Home Depot AttiCat blower.
- Returning bags after a project and dropping below the free-blower minimum — The bag-minimum cliff is not clearly published in either retailer's online policy. If you buy 20 bags for the promo and return 5 after finishing, some stores deduct the standard blower rental (~$75–$100) from your refund. Calculate bag count precisely before purchasing and maintain a buffer above the minimum.
- Comparing AttiCat to cellulose on per-bag price instead of per-sq-ft cost — AttiCat at ~$43/bag covers ~34.5 sq ft at R-30 ($1.25/sq ft); GreenFiber Sanctuary at ~$15/bag covers ~27.4 sq ft at R-30 (~$0.55/sq ft). The per-bag price gap overstates AttiCat's cost disadvantage on a coverage basis — but cellulose still costs significantly less per sq ft at the same R-value.
- Forgetting the cellulose settling buffer — Coverage charts for cellulose already reflect settled R-value at settled thickness, but you need to install to the unsettled depth to hit the target after settling. Cellulose settles 15–20% over 1–2 years per ASTM C739. AttiCat does not settle; its chart reflects final installed depth. Comparing bag counts without accounting for this difference misleads material selection.
- Assuming Lowe's carries AttiCat in the expanding-bag format — Some Lowe's stores carry Owens Corning blown-in fiberglass, but the AttiCat expanding-bagger system (compressed bags + OC-specific blower) is primarily a Home Depot ecosystem. Buying Owens Corning bags at Lowe's may not give you the same format or blower compatibility.
Common Questions
Does Home Depot loan the blower for free with blown-in insulation?
Home Depot typically offers a free 24-hour blower rental with the purchase of 20 or more bags of cellulose insulation. For Owens Corning AttiCat, the minimum is often 10–20 bags depending on the store — AttiCat requires the Owens Corning expanding-bagger blower specifically, not the standard cellulose blower. Confirm the minimum with your specific store before purchasing bags, as terms vary by location and are not uniformly published online.
Can I use the blower from Lowe's for AttiCat insulation?
No — AttiCat requires the Owens Corning expanding-bagger blower, which is specific to Home Depot. The standard cellulose blower at Lowe's is not compatible with AttiCat's compressed-fiberglass bag format. If you plan to use AttiCat, purchase from Home Depot. For cellulose insulation, the standard blower at either retailer works.
What is the minimum bags for a free blower at Lowe's?
Lowe's typically requires a minimum of 20 bags of GreenFiber cellulose insulation to qualify for a free 24-hour blower rental. This minimum applies to standard loose-fill cellulose. Confirm with your specific Lowe's store before purchasing — terms are not uniformly published online and vary by location.
Can I return unused bags of blown-in insulation to Home Depot?
Both HD and Lowe's accept unopened bags within 90 days with receipt. Opened bags are non-returnable. Returning below the free-blower minimum may trigger a rental fee deduction — confirm with your store first.
Which is cheaper: Home Depot or Lowe's for blown-in insulation?
HD vs Lowe's GreenFiber cellulose differs by ~$1–$3/bag. The meaningful comparison is by material type: GreenFiber Sanctuary cellulose ~$13–$22/bag covers ~27–32 sq ft at R-30 (~$0.55/sq ft); Owens Corning AttiCat (HD only) ~$35–$50/bag covers ~34.5 sq ft at R-30 (~$1.25/sq ft). Verify locally; prices vary by region @asOf 2026-Q2.
Estimate your Bag Count Before You Shop
Get estimated bag counts for your attic size and R-value target before comparing retailer prices. The blown-in R-value calculator supports Owens Corning AttiCat (R-2.79/in settled), GreenFiber INS515LD (30 lb, R-3.33/in), GreenFiber INS541LD (19 lb, R-3.22/in), and generic cellulose per FTC R-Value Rule §460.5. Forward mode: enter depth, get R-value. Inverse mode: enter target R, get required depth and bag count.
Open the Blown-In R-Value Calculator →Related Insulation Guides
- Cellulose Insulation Calculator — Borate vs ammonium-sulfate fire retardants, 18–20% ASTM C739 settling factor, brand comparison table (GreenFiber INS515LD: ~31 bags/1,000 sq ft at R-30; ~57 bags at R-49), and air-sealing premium (~10–15% effective R-value loss without sealing).
- AttiCat Blown-In Insulation Guide — Owens Corning AttiCat TDS / L77 coverage chart (~14.6 bags at R-30; ~25 bags at R-49 per 1,000 sq ft per OC TDS), expanding-bag system explained, depth comparison vs cellulose (17.0 in vs 14.8 in at R-49), and DIY install checklist.
- AttiCat R-40 Coverage Chart — bag-count lookup table by attic area (250–3,000 sq ft) for the most common R-40 target. Companion to the AttiCat guide.
- Blown-In Insulation Calculator Guide — Dense-pack vs loose-fill (3.5+ lb/cu ft vs 1.5 lb/cu ft), wet-spray vs dry-blown applications, drill-and-fill wall retrofit, and IRC N1102.4 air-barrier requirements.
- How Much Insulation Do I Need in My Attic? — Full DOE 8-zone R-value targets, energy savings by upgrade scenario, and brand comparison (GreenFiber Cocoon ~33 bags at R-30; Owens Corning AttiCat ~29 bags at R-30 per 1,000 sq ft).
- Insulation R-Value Depth Chart by Brand & Zone — Master depth chart for blown cellulose and fiberglass: Greenfiber INS515LD (R-49: 14.8 in / 56 bags per 1,000 sq ft), Greenfiber INS541LD (R-49: 15.2 in / 83.5 bags), Owens Corning AttiCat fiberglass (R-49: 17.0 in / 25 bags). Reverse lookup: existing depth → current R-value.
- Cellulose R-Value per Inch: Loose-Fill vs Dense-Pack — Per-brand R-per-inch: Greenfiber INS515LD ~3.33 R/in (30 lb bag), INS541LD ~3.22 R/in (19 lb bag). ASTM C739 settling mechanics, FTC 16 CFR Part 460 coverage-chart basis, and depth lookup at R-30/R-38/R-49/R-60 by brand.
- Cellulose Insulation Thickness Chart by R-Value — Cellulose depth chart: INS515LD ~14.8 in at R-49, INS541LD ~15.2 in, Applegate ~15.0 in. ASTM C739 settling rule applied directly to install-depth math.
Estimates only — verify with your local building authority and a qualified contractor before construction. See our full disclaimer.