Seattle Insulation Cost Calculator
Estimate 2026 Seattle insulation: blown-in or batt attic insulation, removing old attic insulation, attic air sealing, batts in open walls, crawl space insulation and a crawl space vapor barrier. Set the square footage for each item, and the calculator totals the installed prices. Blowing in 1,000 sq ft of attic insulation to R-49 comes to about $1,425.
Finishing a basement? The basement calculator prices wall and ceiling insulation as part of the finish. Re-siding the house? The siding calculator can add insulation behind the new siding. For a firm number, request a quote.
Your Estimate
Pick what you need and click Calculate
Each item shows its installed price per unit
What this calculator captures
Installed prices from this calculator for a 1,000 sq ft attic. Wall, crawl space and vapor barrier work is priced in the calculator above.
- Attic air sealing
- About $475
- Attic blown in to R-49
- About $1,425
- Old insulation out, sealed, R-49 in
- About $2,850
Sealing gaps and penetrations in a small to mid-size attic.
1,000 sq ft of blown-in cellulose or fiberglass, materials and installation.
1,000 sq ft of old insulation removed, the attic air sealed, and new insulation blown in to R-49.
Using this calculator
What does each price include?
Attic blown-in is cellulose or fiberglass blown in to R-49, and attic batts are fiberglass batts laid in the attic, both with materials and installation. Removal covers clean old insulation before the new insulation goes in. Air sealing covers the gaps and penetrations in a small to mid-size attic. Wall insulation is fiberglass batts in open exterior wall cavities, crawl space insulation is batts fitted between the floor joists, and the vapor barrier is 6-mil, laid over the crawl space floor.
Is there a job minimum?
Yes, $475. When a job totals less, the difference is added as its own Mobilization & Job Minimum line, so the line items still add up to the total. Attic air sealing is $475 on its own; 300 sq ft of attic batts ($354) prices at $475.
What does it cost to redo an attic?
Removing 1,000 sq ft of old attic insulation, air sealing the attic and blowing in new insulation to R-49 comes to about $2,850. Blowing in new insulation over the same 1,000 sq ft, without the removal and air sealing, comes to about $1,425.
How are these prices set?
Each item's price is set against the lowest installed price that registered Seattle-area contractors publish on their own websites for the same scope, dated 2025 or 2026, at about 95% of it. Lead-generation and pricing-template sites never set a price, and neither do Kolmo's own quotes. The full method is at /how-estimates-work.
What doesn't the calculator price yet?
Spray foam, and insulation blown into closed walls, are not in the calculator yet; they are quoted after a walkthrough.
Keep planning
Continue the planning once you have a number.