Spray Foam vs Blown-In Insulation for Existing Walls

Assessment First

Energy audit identifies priorities. Air leaks major concern. Insulation effectiveness measured. Payback period calculated.

Attic Priority

Heat rises and escapes. R-38 to R-60 recommended. Air sealing before insulation. Ventilation maintained properly.

Wall Options

Blown-in fills existing walls. Exterior continuous insulation thorough. Dense-pack cellulose effective. Spray foam seals and insulates.

Basement and Crawl

Rim joist often neglected. Floor insulation depends on use. Vapor barriers properly placed. Encapsulation for crawl spaces.

For a brand-specific bid review, see our 2026 USA Insulation review, cost and red-flag guide.