Attic Insulation Cost (2026): Blown-In vs Batts
Updated
Attic insulation costs about $1 to $2.50 per square foot installed, or $1,500 to $3,500 for a typical attic. Blown-in cellulose and fiberglass are the most common and cost-effective. Topping up an under-insulated attic to R-49–R-60 often pays back in energy savings within a few years.
The attic is the highest-return place to insulate in almost any home, because heat rises and escapes there first. Whether you're insulating a bare attic or topping up thin insulation, knowing the cost helps you judge the payback.
This guide covers attic insulation costs in 2026 by type and size, the R-value to aim for, and how quickly it pays for itself.
Key takeaways
- Attic insulation costs about $1–$2.50 per square foot installed.
- A typical attic runs $1,500–$3,500.
- Blown-in is fastest and best for irregular attics.
- Target R-49 to R-60 in most climates.
- Often pays back in energy savings within 2–4 years.
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Attic insulation cost by type
| Type | Cost per ft² | Notes |
|---|---|---|
| Blown-in fiberglass | $1.00 – $2.00 | Fast, fills gaps |
| Blown-in cellulose | $1.00 – $2.50 | Eco, dense |
| Fiberglass batts | $1.00 – $2.40 | DIY-friendly |
| Spray foam | $3.00 – $7.00 | Air-seals, premium |
Cost by attic size
| Attic floor area | Typical installed cost |
|---|---|
| 500 ft² | $750 – $1,500 |
| 1,000 ft² | $1,500 – $3,000 |
| 1,500 ft² | $2,250 – $4,500 |
What R-value to target
Most attics should reach R-49 to R-60 (about 16–20 inches of blown-in). In warmer southern climates R-38 may suffice. Air-seal gaps and penetrations before adding insulation for full performance.
The payback
An under-insulated attic can waste 15–25% of heating and cooling energy. Topping it up often pays for itself within 2–4 years, then keeps saving. Estimate your job with our insulation calculator.