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Insulation Cost Guides

Attic & home insulation costs. Reviewed planning information and transparent cost assumptions.

Insulation contractor in protective suit and respirator spraying expanding foam insulation into open wall cavities between wooden studs

Spray Foam Insulation Cost in 2026: What You Will Pay

Spray foam insulation costs $2,888 on average in 2026, $0.60 to $3.10 per board foot installed. Open-cell runs $0.60 to $1.60, closed-cell $1.30 to $3.10. See why quotes vary 3x, when DIY kits pay off, and the real payback by climate.

$1,000.00 – $9,000.00 per project

Reviewed 2026-10-13 · 10 sources cited

Blown-in insulation covering an attic floor between joists

Attic Insulation Cost in 2026: Price per Sq Ft

Attic insulation costs $2,100 on national average, with most projects between $1,000 and $2,700. Expect $1 to $3 per square foot installed. Blown-in fiberglass or cellulose is cheapest at $0.90 to $2.40 per sq ft; spray foam runs $1 to $4.50.

$500.00 – $6,000.00 per project

Reviewed 2026-10-10 · 10 sources cited