Insulation cost by area and type
Estimates from this calculator's default prices for an attic floor with no insulation worth keeping, filled to R-49, and no removal. Change the defaults above to match quotes or prices near you.
| Attic floor area | Blown-in cellulose, R-49 | Blown-in fiberglass, R-49 |
|---|---|---|
| 500 sq ft | $800–$1,200 | $1,010–$1,510 |
| 1,000 sq ft | $1,450–$2,150 | $1,800–$2,700 |
| 1,500 sq ft | $2,050–$3,100 | $2,650–$3,950 |
| 2,000 sq ft | $2,700–$4,000 | $3,450–$5,150 |
Per 1,000 sq ft, other common jobs come to about $1,130–$1,700 for R-13 batts in open walls, $1,600–$2,350 for R-19 batts under a crawl space floor, and $2,350–$3,550 for open-cell spray foam in open walls.
Attic and blow-in insulation cost
Blowing loose fill onto the attic floor is usually the cheapest way to insulate. With these defaults, 1,000 sq ft of blown-in cellulose to R-49 costs about $1,450–$2,150, or $1.79 per sq ft. Blown fiberglass to the same R-value is about $1,800–$2,700, because it takes more bags to reach R-49 at these prices.
Most attics already have some insulation. Topping up R-19 of old insulation to R-49 with cellulose comes to about $1,060–$1,580. Removing the old insulation first raises a fresh R-49 job to about $2,250–$3,350. A lower target cuts the price: R-38 cellulose is about $1,200–$1,850.
Spray foam insulation cost
Spray foam is sold by the board foot: 1 sq ft, 1 in thick. In 1,000 sq ft of open 2×4 walls, open-cell foam to R-13 (3.5 in) comes to about $2,350–$3,550 with these defaults, or $2.95 per sq ft. Closed-cell foam reaches R-13 in 2 in but costs more per board foot: about $2,900–$4,350, or $3.63 per sq ft. At R-19 closed-cell, it's about $3,900–$5,800. The estimate includes $400 per job for the spray rig and setup.
Crawl space insulation cost
Insulating the floor above a crawl space with R-19 batts comes to about $1,600–$2,350 per 1,000 sq ft with these defaults. Labor is 40% slower than in an open attic because the work is overhead in a tight space. Closed-cell foam to R-19 in the same space is about $4,000–$6,000. Many crawl spaces also need moisture control first, which isn't in this estimate.
What changes the price
- Target R-value: loose fill and foam cost roughly in proportion to the R-value added. Recommended attic levels depend on your climate zone.
- What's there now: keeping old insulation that's dry and clean lowers the cost; removing wet, moldy or damaged insulation raises it.
- Access: low attics, crawl spaces and finished walls take longer. Closed walls need dense-pack or injection, which this estimate doesn't model.
- Air sealing: sealing gaps around lights, pipes and the attic hatch before insulating is often quoted as a separate line.
- Incentives: federal and utility incentives may apply to insulation. Check current rules before you sign.
How this estimate works
Quantities follow our insulation calculator. Loose fill is counted in bags from the coverage at R-30 on the bag, scaled to your R-value, plus 5%: fiberglass bags cover 40 sq ft at R-30 and cellulose bags 22 sq ft, at contractor prices of $34 and $13 a bag (the calculator's retail defaults are $42 and $16). Batts are $0.55 per sq ft for each R-10 (so R-13 is about $0.72), plus 5%. Spray foam is $0.45 per board foot for open-cell at R-3.7 per inch and $1.00 for closed-cell at R-6.5 per inch, plus 10%.
Labor uses the calculator's rates: 250 sq ft per hour for blown fiberglass, 200 for cellulose and open-cell foam, 150 for batts and closed-cell foam, plus an hour of setup for blown and foam jobs. Walls take 10% longer and crawl spaces 40% longer. Labor is billed at $70 per worker hour, including the contractor's overhead and profit, the markup on materials is 20%, equipment and setup is $150 per job for blown insulation and $400 for spray foam, and removal is $1 per sq ft. The range is the result minus 20% to plus 20%. Change any of these above.
For comparison, Homewyse lists loose fill insulation at $1.68–$2.94 per sq ft, blown-in cellulose at $1.67–$2.92 and batt wall insulation at $1.67–$2.76 (May 2026 figures, accessed November 2026). With these defaults we get $2.25 per sq ft for blown fiberglass and $1.79 for cellulose at R-49, and $1.41 for R-13 batts, which is below Homewyse's batt range. Homewyse's separate blown-in attic insulation estimate, priced at R-45, is higher at $3.75–$7.77 per sq ft, so get local quotes.
Getting quotes
Compare quotes on the R-value installed (not just inches), the material, whether air sealing and baffles are included, and removal of old insulation. Ask for the installed depth to be marked in the attic.
Questions
How much does attic insulation cost?
With this calculator's typical defaults, blowing cellulose to R-49 over 1,000 sq ft of attic floor costs about $1,450–$2,150. Blown fiberglass is about $1,800–$2,700.
How much does spray foam insulation cost per square foot?
In open walls with these defaults, about $2.95 per sq ft for open-cell foam at R-13 and $3.63 for closed-cell at R-13, including setup, for 1,000 sq ft.
Is blown-in insulation cheaper than batts?
For attic floors, usually. Loose fill goes in fast and fills around obstructions. Batts suit open walls and floors, where R-13 runs about $1,130–$1,700 per 1,000 sq ft here.
Can I blow in attic insulation myself?
Many people do. Materials for 1,000 sq ft of cellulose at R-49 are about $1,014 at contractor prices in this estimate; retail bags cost a little more, and many stores lend or rent the blowing machine. Wear a respirator and stay on the joists.