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Blown-In Insulation Cost Calculator
Can I DIY? · DIY-FriendlyCalculate blown-in insulation costs by material, area, and R-value target — with energy savings projections.
Educational calculators — always consult a licensed professional before making financial decisions.
Smaller ranch homes or partial attics. Typical for homes under 1,000 sq ft.
Recycled paper fiber. R-3.7 per inch, excellent air sealing, eco-friendly. Best cost-per-R-value.
No existing insulation or you're unsure. Will estimate full insulation cost from scratch.
DOE minimum for warm southern climates (Climate Zones 1–3).
Likely has little or no attic insulation, or possibly asbestos-containing materials. Get an inspection first.
Estimated Insulation Cost
$850 – $1,440
9" needed · 26 bags
Cost Breakdown
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Estimates based on national averages. Actual costs vary by region and contractor.
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How it works
Enter area and R-value target
Provide the square footage to insulate and your climate zone's target R-value.
Select material type
Cellulose, fiberglass, and mineral wool each have different R-values per inch.
See cost and energy savings
Get total installed cost and estimated annual energy savings. Note: the federal §25C insulation credit ended after Dec 31, 2025, so no federal credit is applied to 2026 work.
Blown-In Insulation Cost by Type
| Type | R-Value/Inch | Cost/Sq Ft Installed |
|---|---|---|
| Cellulose | R-3.7 | $1.00 – $2.80 |
| Fiberglass | R-2.5 | $1.50 – $3.50 |
| Deep-fill / high R-value | — | $3.00 – $4.50 |
Cellulose vs. fiberglass, and R-value
- Cellulose: higher R-value per inch (~R-3.7), recycled content, blocks air movement well, and is usually the cheaper of the two. Best value for most attics.
- Fiberglass: lighter, doesn't settle as much, resists moisture and mold. Slightly lower R-value per inch (~R-2.5).
- Target R-value: the DOE recommends R-38 to R-60 for attics by climate zone. Going from R-11 to R-49 typically cuts heating and cooling bills 15–25%.
What's included, DIY, and rebates
A pro quote usually covers material, machine blowing, and depth markers; extra costs include air-sealing, attic prep, baffles at the eaves, and removing contaminated old insulation. Blown-in is DIY-friendly — home centers rent the blower, saving 40–60% on labor — but air-sealing first is what really pays off.
Rebates: the federal 25C insulation credit ended after Dec 31, 2025, but many state and utility programs still offer insulation rebates — check DSIRE (dsireusa.org) before you start.
Questions to ask — and red flags
- Will you air-seal top plates and penetrations before blowing?
- What final R-value and depth, and will you install baffles at the eaves?
- Is my old insulation tested for pests/mold before topping up? (Blowing over contaminated insulation just buries the problem.)
Methodology & sources
The cost figures on this page are generated from a single, sourced cost-data file (Per sq ft installed by material. National average estimate for 2026 ($900–$3,600 for a typical attic).). Cellulose has a higher R-value per inch and is usually cheaper; fiberglass resists moisture better. DIY with a rented blower can lower labor 40–60%. Last verified July 2026.
- HomeGuide — Blown-In Insulation Cost (2026) — retrieved 2026-07-13
- Angi — Blown-In Insulation Cost (2026) — retrieved 2026-07-13
About this calculator
How much does blown-in insulation cost?+
Blown-in insulation costs $1–$4.50 per sq ft installed depending on material and R-value target. Cellulose runs $1–$2.80/sq ft. Fiberglass blown-in runs $1.50–$3.50/sq ft. Deep-fill work to a high R-value target runs $3–$4.50/sq ft. A typical attic costs $900–$3,600 installed. DIY is possible with rented machines from home improvement stores at a savings of 40–60% on labor.
Cellulose vs. fiberglass blown-in insulation: which is better?+
Cellulose has a higher R-value per inch (R-3.7 vs R-2.5 for fiberglass), resists air movement better, uses 85% recycled content, and is typically 10–15% less expensive. Fiberglass is lighter, doesn't settle as much over time, and is resistant to mold. For most attic applications, cellulose is the better value. For walls where moisture resistance matters more, fiberglass is preferred.
How thick should blown-in insulation be?+
Thickness depends on your target R-value and material. For R-49 (recommended for northern US): cellulose needs about 13 inches, fiberglass needs about 20 inches. For R-38: cellulose needs about 10 inches, fiberglass needs about 15 inches. Bags of insulation state the thickness needed per bag for your target R-value — use those charts for accurate ordering.
Is blown-in insulation eligible for a tax credit in 2026?+
No federal credit for 2026 work. The 25C Energy Efficient Home Improvement Credit — 30% of material costs up to $1,200 per year — ended for insulation placed in service after December 31, 2025 (One Big Beautiful Bill Act, 2025). Insulation installed by December 31, 2025 can still be claimed on your 2025 return (IRS Form 5695). Many states and utilities still offer insulation rebates — search DSIRE (dsireusa.org) by your ZIP.
Want to try different numbers?
Back to the calculator ↑Blown-In Insulation Cost Calculator is built and maintained by the RealCostIQ editorial team. Cost ranges and rates are checked against published industry data and contractor quotes, and revised when the underlying figures move. Read our data methodology or more about who builds this. Every calculation runs in your browser — no account, and none of your inputs are stored.
Cost ranges and rates here are checked against contractor quotes and published industry data. If a number still looks off, email Support@RealCostIQ.com and we'll review and fix it.