How Much Does Insulation Cost In Your Area?

A typical 1,500 sq ft attic costs $1,500 to $3,500 for blown-in cellulose or fiberglass to R-49 or R-60. Spray foam runs $3,000 to $6,000 for the same attic. Add $300 to $800 for air sealing the gaps around recessed lights, ducts, and the attic hatch. Most attics in homes built before 2000 are under-insulated and the upgrade pays for itself in 3 to 7 years.

Fiberglass batts at $0.50 to $1.50 per sq ft are cheapest and easiest for open attic spaces. Blown-in cellulose at $1 to $2 per sq ft fills gaps better and uses recycled paper. Spray foam at $1.50 to $4 per sq ft seals air leaks while insulating but costs the most. Most US attics get blown-in cellulose for the price-to-performance ratio. Spray foam is the right choice for crawl spaces, rim joists, and basement walls.

Department of Energy guidelines call for R-49 to R-60 for attics in cold climates like the Northeast and Midwest, R-38 to R-49 for mixed climates, and R-30 to R-38 for warm climates like the Gulf states. R-49 of cellulose is about 14 inches deep. R-60 is about 17 inches. Most homes built before 2000 have R-19 to R-30, so adding 8 to 12 inches gets you to current code.

Yes, in most cases. Topping up existing fiberglass or cellulose with more of the same material is the standard approach and avoids the cost of removing the old insulation. The exception is when the existing insulation is wet, moldy, or rodent-damaged, which adds $1,000 to $3,000 for removal first. A good contractor inspects with a flashlight before quoting and will flag removal needs in writing.

Blown-in attic insulation for a typical home wraps up in 3 to 6 hours. Wall insulation by drill-and-fill blown-in takes 1 to 2 days. Spray foam in an attic or crawl space takes 1 to 2 days plus 24 hours of cure time before you can re-enter the space. Whole-home insulation upgrades for new construction or major renovations take 3 to 5 days. Most installs let you stay home during the work.

Closed-cell spray foam at $2 to $4 per sq ft costs 2 to 4 times more than blown-in but seals air leaks while insulating, with R-values of 6 to 7 per inch versus 3.5 for cellulose. It is worth the upgrade for crawl spaces, basement rim joists, and homes with chronic drafts. For a typical open attic floor, blown-in cellulose with separate air sealing usually beats spray foam on cost-effectiveness.

The federal Energy Efficient Home Improvement Credit covers 30% of insulation costs up to $1,200 per year through 2032. Most major US utilities offer rebates of $100 to $1,000 for attic insulation upgrades. State programs in California, Massachusetts, New York, and Colorado often add another $200 to $1,500. Stack all three and a $3,000 attic upgrade can net out around $1,500 to $2,000 after credits and rebates.