Most homeowners pay about $1,700 to $2,500 to insulate an attic - roughly $1 to $3 per square foot installed, with a national average near $2,100 (HomeAdvisor, 2026). Blown-in fiberglass sits at the low end; spray foam runs highest. Your final price depends on attic size, the R-value you target, and how accessible the space is.
The figures on this page are national averages. Your local quote will vary with labor rates, attic condition, and the material you choose.
What is the average cost to insulate an attic?
Across the US, attic insulation averages about $2,100, with a typical range of $1,700 to $2,500 (HomeAdvisor, 2026). A separate estimate puts the national average at $2,500, spanning $1,500 to $3,500 (Bob Vila, 2023). Because most of the cost is priced by the square foot, attic size is the single biggest driver.
| Attic size | Estimated installed cost | Source |
|---|---|---|
| 300 sq ft | $300-$900 | HomeAdvisor, 2026 |
| 500 sq ft | $500-$1,500 | HomeAdvisor, 2026 |
| 800 sq ft | $800-$2,400 | HomeAdvisor, 2026 |
| 1,000 sq ft | $1,000-$3,000 | HomeAdvisor, 2026 |
| 1,500 sq ft | $1,500-$4,500 | HomeAdvisor, 2026 |
What does attic insulation cost per square foot by material?
Attic insulation runs about $1 to $3 per square foot installed for most materials (HomeAdvisor, 2026). Across all types the spread is wider - roughly $0.50 to $7 per square foot. Reflective barriers and blown-in loose-fill are the least expensive; spray foam and structural panels sit at the top.
| Insulation type | Installed cost per sq ft | Source |
|---|---|---|
| Reflective / radiant barrier | $0.50-$2 | HomeAdvisor, 2026 |
| Blown-in | $1-$4 | HomeAdvisor, 2026 |
| Batt (fiberglass) | $2-$4 | HomeAdvisor, 2026 |
| Loose-fill | $2-$5 | HomeAdvisor, 2026 |
| Spray foam | $2-$5 | HomeAdvisor, 2026 |
| Structural insulated panels | $4-$7 | HomeAdvisor, 2026 |
How much does blown-in attic insulation cost?
Blown-in attic insulation averages about $1,660 for a typical job, with most homeowners spending between $986 and $2,333 (HomeAdvisor, 2025). By material, blown-in fiberglass is the least expensive at $0.50 to $1.10 per square foot, while cellulose ranges from $0.60 up to about $2.30 per square foot for dense-pack.
Blown-in is popular for attics because the loose fibers fill gaps and settle around joists and wiring. Whole-project pricing works out to roughly $1.75 to $7.50 per square foot once labor is included (HomeAdvisor, 2025). For a per-material breakdown, see our [blown-in insulation cost per square foot](/guides/blown-in-insulation-cost-per-square-foot/) guide.
| Blown-in material | Cost per sq ft | Source |
|---|---|---|
| Fiberglass | $0.50-$1.10 | HomeAdvisor, 2025 |
| Cellulose (wet-spray) | $0.60-$1.80 | HomeAdvisor, 2025 |
| Cellulose (dense-pack) | $2.00-$2.30 | HomeAdvisor, 2025 |
| Mineral wool (Rockwool) | $1.40-$2.10 | HomeAdvisor, 2025 |
How much does it cost to remove old attic insulation?
Removing old attic insulation typically costs $1 to $2 per square foot, or about $600 to $1,200 for a standard attic - roughly $900 on average (HomeAdvisor, 2026). Price climbs when the material is wet, compacted, or contaminated: asbestos abatement adds $1,190 to $3,255, and mold remediation adds $1,225 to $3,750. Removal is a separate line item from installing new insulation - see our [attic insulation removal cost](/guides/attic-insulation-removal-cost/) guide for the full breakdown.
| Job | Typical cost | Source |
|---|---|---|
| Remove old insulation (labor) | $1-$2 per sq ft | HomeAdvisor, 2026 |
| Remove old insulation (whole attic) | $600-$1,200 (avg ~$900) | HomeAdvisor, 2026 |
| Remove and replace insulation | ~$1,852 average | HomeAdvisor, 2026 |
| Asbestos abatement (if found) | $1,190-$3,255 | HomeAdvisor, 2026 |
| Mold remediation (if found) | $1,225-$3,750 | HomeAdvisor, 2026 |
What makes attic insulation cost more or less?
Three things move the price most: attic size (you pay by the square foot), the R-value you target, and how easy the space is to reach. ENERGY STAR recommends attic insulation between R-30 and R-60 depending on your climate zone - hitting a higher R-value means more material, and more cost. Tight, low-clearance attics raise labor.
Beyond size and R-value, expect add-ons. Air sealing gaps before insulating typically runs $250 to $750 (HomeAdvisor, 2026), and any old material that has to come out adds the removal cost shown above. A federal tax credit that covered 30% of insulation material costs, up to $1,200 a year, applied to work completed through December 31, 2025, but was not renewed for 2026 (ENERGY STAR; IRS).
Related questions
Sources
6 cited- Attic insulation average cost and per-square-foot pricing by attic size: HomeAdvisor, Attic Insulation Cost (checked 2026-08-19).
- Cost per square foot by material, and blown-in fiberglass vs cellulose breakdown: HomeAdvisor, Blown-In Insulation Cost, 2025 (checked 2026-08-19).
- Alternate national average: Bob Vila, How Much Does Attic Insulation Cost?, 2023 (checked 2026-08-19).
- Removal, remove-and-replace, asbestos abatement and mold remediation cost: HomeAdvisor, Insulation Removal Cost (checked 2026-08-19).
- Federal insulation tax credit terms and 2025 expiration: ENERGY STAR, Insulation Tax Credit; IRS, Energy Efficient Home Improvement Credit, Section 25C (checked 2026-08-19).
- Recommended R-30 to R-60 attic target: ENERGY STAR, Recommended Home Insulation R-Values (checked 2026-08-19).