Attic Insulation Calculator
Estimated Total Cost
$1,350 – $3,000
$1.35 – $3.00 per sq ft (installed)
Material
$600 – $1,500
Labor
$750 – $1,500
Attic Area
1,000 sq ft
Insulation
Blown-In Fiberglass
Tip: Check for utility rebates and federal tax credits before starting. Many utilities offer $0.10–$0.50/sq ft rebates, and the federal tax credit covers 30% of insulation costs up to $1,200/year.
Blown-In Fiberglass: Fills gaps and irregular spaces evenly. R-2.5 per inch. Lightweight and non-settling. Good for adding on top of existing insulation in attics.
Disclaimer: Estimates are for budgeting purposes only. Actual costs vary by location, contractor, material availability, and project complexity. Always get professional quotes for exact pricing.
Attic Insulation Cost Breakdown
| Insulation Type | Material / Sq Ft | Labor / Sq Ft | Total / Sq Ft |
|---|---|---|---|
| Fiberglass Batts | $0.50 – $1.25 | $0.75 – $1.75 | $1.25 – $3.00 |
| Blown-In Fiberglass | $0.60 – $1.50 | $0.75 – $1.50 | $1.35 – $3.00 |
| Blown-In Cellulose | $0.50 – $1.25 | $0.75 – $1.50 | $1.25 – $2.75 |
| Open-Cell Spray Foam | $0.75 – $2.00 | $0.75 – $1.50 | $1.50 – $3.50 |
| Closed-Cell Spray Foam | $1.25 – $3.00 | $1.00 – $2.00 | $2.25 – $5.00 |
* Costs shown for standard attic (1.0× labor). Hard-to-access adds 20%, remove old insulation adds 15% to labor.
Average Attic Insulation Projects
| Project | Attic Size | Insulation | Estimated Total |
|---|---|---|---|
| Small Attic | 500 sq ft | Fiberglass Batts | $625 – $1,500 |
| Standard Attic | 1,000 sq ft | Blown-In Fiberglass | $1,350 – $3,000 |
| Large Attic | 1,500 sq ft | Blown-In Cellulose | $1,875 – $4,125 |
| Energy Upgrade | 1,200 sq ft | Closed-Cell Spray Foam | $2,700 – $6,000 |
How We Calculate
Our attic insulation calculator estimates project costs based on attic area, insulation type, and attic condition. Material and labor costs are calculated per square foot, with labor adjusted by a condition multiplier.
How the math works: Material cost = area × material price per sq ft. Labor cost = area × labor rate per sq ft × condition multiplier. Total = material + labor. The condition multiplier adjusts labor: standard attic is 1.0×, hard-to-access attic adds 20% (1.2×), and removing old insulation first adds 15% (1.15×) for extraction and disposal.
Insulation Type Comparison
Fiberglass Batts ($0.50–$1.25/sq ft material, $0.75–$1.75/sq ft labor) are the most affordable and widely available. R-3.2 per inch. Best for open attic floors with standard joist spacing. DIY-friendly for accessible attics.
Blown-In Fiberglass ($0.60–$1.50/sq ft material, $0.75–$1.50/sq ft labor) fills gaps and irregular spaces evenly. R-2.5 per inch. Lightweight and non-settling. Good for adding on top of existing insulation.
Blown-In Cellulose ($0.50–$1.25/sq ft material, $0.75–$1.50/sq ft labor) offers R-3.5 per inch. Made from recycled paper treated for fire and pest resistance. Settles 10–20% over time.
Open-Cell Spray Foam ($0.75–$2.00/sq ft material, $0.75–$1.50/sq ft labor) expands to fill every crack. R-3.7 per inch. Excellent air sealing. Not a vapor barrier — requires separate vapor retarder in cold climates.
Closed-Cell Spray Foam ($1.25–$3.00/sq ft material, $1.00–$2.00/sq ft labor) has the highest R-value at R-6.5 per inch. Acts as insulation and vapor barrier. Most expensive but highest performance.
Additional Cost Factors
Our estimates cover insulation material and installation labor. Not included: air sealing before insulation ($300–$800), attic access improvements ($200–$500), ventilation baffles ($1–$3 each), old insulation removal if contaminated ($1–$2/sq ft), and any structural repairs. Many contractors include basic air sealing with insulation projects.
Data Sources
Pricing data is compiled from HomeAdvisor, Angi, insulation manufacturers, and verified contractor estimates across multiple US regions. We review and update this data regularly.
Last updated: 2026-02-02
Frequently Asked Questions
How much does attic insulation cost? +
Attic insulation costs $1.25–$5.00 per square foot installed, depending on type. Fiberglass batts are $1.25–$3.00/sq ft, blown-in fiberglass $1.35–$3.00/sq ft, blown-in cellulose $1.25–$2.75/sq ft, open-cell spray foam $1.50–$3.50/sq ft, and closed-cell spray foam $2.25–$5.00/sq ft. A typical 1,000 sq ft attic costs $1,350–$3,000 with blown-in fiberglass.
What R-value do I need for attic insulation? +
The DOE recommends R-38 to R-60 for attic insulation in most US climate zones. Cold climates (zones 5–8) need R-49 to R-60. Moderate climates (zones 3–4) need R-38 to R-49. Hot climates (zones 1–2) need R-30 to R-38. Check the DOE insulation map for your specific zone.
What is the best attic insulation type? +
Blown-in insulation (fiberglass or cellulose) is best for most attics. It fills gaps evenly, works in irregular spaces, and provides good coverage. Spray foam offers superior air sealing but costs more. Fiberglass batts are the most affordable for open, accessible attics with standard joist spacing.
Can I add insulation on top of existing insulation? +
Yes, in most cases you can add new insulation on top of existing insulation. Blown-in insulation is ideal for topping off. Do not add insulation over wet, moldy, or pest-damaged existing material — remove it first. Ensure attic ventilation is maintained and vapor barriers are properly placed.
How long does attic insulation last? +
Fiberglass insulation lasts 80–100 years if undisturbed. Cellulose lasts 20–30 years before settling reduces effectiveness. Spray foam lasts 80+ years. In practice, most attics need topping off every 15–25 years as insulation compresses and settles over time.
Are there rebates or tax credits for attic insulation? +
Yes, the federal Inflation Reduction Act provides a 30% tax credit up to $1,200/year for insulation upgrades. Many utilities also offer rebates of $0.10–$0.50/sq ft. Some states have additional programs. Check DSIRE (dsireusa.org) and your utility company for available incentives.
Should I remove old insulation before adding new? +
Remove old insulation if it is water-damaged, mold-contaminated, has pest infestations, or contains vermiculite (possible asbestos). Removal adds 15% to labor costs. If the existing insulation is clean and dry, you can add new material on top to reach your target R-value.
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