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Crawl-space duct replacement cost calculator
Crawl-space ductwork replacement cost depends on clearance, moisture, access points, insulation, supply and return layout, pest or mold exclusions, and whether vapor-barrier or floor repairs are separate from the HVAC work.
Direct answer
$3,500-$12,000+
A short accessible section may cost about $1,500-$4,500, while full crawl-space duct replacement commonly reaches $3,500-$12,000 or more. Low clearance, standing moisture, damaged insulation, and return-air changes can increase labor and remediation scope.
| Scope | Planning range | What the quote should explain |
|---|---|---|
| One damaged crawl-space section | $1,500-$4,500 | Affected footage, connection repair, insulation, supports, sealing, access, and airflow verification. |
| Partial crawl-space replacement | $2,800-$7,000 | Several branches or a trunk section, damaged insulation removal, supports, sealing, and balancing. |
| Full crawl-space duct replacement | $3,500-$12,000+ | Supply and return design, insulated ducts, plenums, access labor, removal, testing, cleanup, and permit assumptions. |
| Cost factor | Lower-cost condition | Higher-cost condition |
|---|---|---|
| Clearance | Dry, open, easy entry | Low clearance, narrow access, piers, or obstructions |
| Moisture | Dry materials and intact insulation | Standing water, condensation, damaged insulation, or separate remediation |
| Duct condition | One disconnected or crushed run | Widespread corrosion, contamination, poor supports, or undersized returns |
| Related repairs | HVAC-only access and cleanup | Vapor barrier, floor opening, pest, mold, asbestos, or drainage work |
A broad full-replacement planning range is about $3,500-$12,000 or more. Partial work may start around $1,500. Clearance, moisture, home size, return-air changes, insulation, removal, and related repairs determine the final bid.
Often. Wet insulation, condensation, standing water, corrosion, mold concerns, or a damaged vapor barrier can require separate diagnosis and remediation before or alongside duct replacement.
An isolated disconnected joint or crushed section may be repairable. Widespread damage, poor insulation, contamination, corrosion, undersized returns, or a flawed layout can support a larger replacement after inspection and airflow testing.
The quote should identify duct sizes and material, supplies and returns, insulation, supports, sealing, removal, access, moisture-related exclusions, vapor-barrier responsibility, testing, cleanup, permits, and labor warranty.
Clear HVAC Costs models duct replacement from home size, partial or full scope, installation location, access difficulty, return-air work, and insulation. Results are U.S. homeowner planning ranges, not bids. Compare at least three written contractor quotes. Last updated September 7, 2026.