Replacing AC ducts in an attic typically costs homeowners between $1,200 and $7,500 depending on system size, duct material, attic access, and whether insulation or sealing is included. This article shows typical cost ranges, per-foot pricing, and the main drivers that determine the final cost to replace AC ducts in an attic.
| Item | Low | Average | High | Notes |
|---|---|---|---|---|
| Full attic duct replacement (single-story home) | $1,200 | $3,200 | $7,500 | Assumes 600–1,200 sq ft of ducts, flexible duct, standard access |
| Per linear foot (materials + labor) | $4 per ft | $8 per ft | $15 per ft | Varies by material and insulation R-value |
| Duct sealing & insulation add-on | $200 | $750 | $2,500 | Depends on square footage and R-value |
| Remove & dispose old ducts | $100 | $350 | $1,200 | Access and contamination raise cost |
Typical Price to Replace AC Ducts in an Attic
Homeowners usually pay $1,200-$7,500 total to replace attic AC ducts, with an average around $3,200 for a typical single-story home. This range assumes 600–1,200 linear feet of ductwork, use of insulated flex duct or sheet metal trunk lines, and normal attic access in suburban U.S. markets. Assumptions: standard labor rates, no major joist modifications, moderate insulation.
Material, Labor, Equipment, and Disposal Pricing
Major quote lines normally include materials, labor, equipment, and disposal; together these form most of the invoice.
| Materials | Labor | Equipment | Delivery/Disposal |
|---|---|---|---|
| $4-$10 per ft (flex duct), $8-$25 per ft (sheet metal) | $75-$125 per hour; $600-$2,500 total | $100-$600 (lift rental, scaffolding if needed) | $100-$1,200 depending on contamination |
How Duct Length, Diameter, and Insulation R-Value Change the Quote
Price scales directly with linear footage and duct diameter; expect a 20%-60% jump when moving from 6″ to 12″ trunks or increasing R-value from R4 to R8. Example thresholds: under 200 ft is a small job, 200–800 ft is medium, and over 800 ft is large (each tier raises labor mobilization and time). Also factor increased material costs when upgrading from flex to spiral or rigid sheet metal.
Practical Ways to Lower the Cost of Attic Duct Replacement
Control scope: replace only damaged runs, re-line instead of full replacement, and schedule work in shoulder seasons to lower cost. Other tactics include providing attic access, clearing staging areas, choosing insulated flex duct instead of custom-fabricated sheet metal, and grouping HVAC projects to reduce mobilization fees.
Regional Pricing Differences for Attic Duct Replacement
Expect 10%-30% regional variance; coastal and high-cost metro areas are higher while Midwest and rural areas trend lower. Typical deltas: Northeast/West Coast +15% to +30% vs. national average, Mountain Plains -5% to -15%, South -5% to +5% depending on metro area. Assumptions: similar job size and materials.
Typical Labor Time, Crew Size, and Hourly Rates for Attic Jobs
A standard medium attic duct replacement takes 10–24 hours with a 2–3 person crew; labor is commonly billed at $75-$125 per hour per technician. Use the mini-formula to estimate labor cost; example: 16 hours × $95/hr ≈ $1,520 in labor.
Common Add-Ons: Removal, Sealing, Inspections, and Repairs
Typical add-ons increase the total by $200-$2,500 depending on scope—air sealing, mold remediation, or insulation upgrades are the costliest. Typical ranges: leak sealing $200-$800, mold/contamination remediation $500-$2,500, attic insulation around duct runs $400-$1,800, HVAC balancing/testing $150-$400.
Three Real-World Quote Examples With Specs and Costs
Sample quotes illustrate how scope and materials produce wide price variance on attic duct replacements.
| Job | Specs | Labor Hours | Per-Unit Pricing | Total |
|---|---|---|---|---|
| Small condo run | 150 ft flex, R6, easy access | 8 | $6 per ft | $900-$1,200 |
| Typical 1,400 sq ft house | 600 ft mixed flex/trunk, R8, attic hatch | 16 | $8 per ft | $3,200-$3,800 |
| Large multi-branch job | 1,200 ft sheet metal trunks + insulated flex | 30 | $12 per ft | $8,000-$9,500 |