How Much Does It Cost to Replace AC Ductwork

Introduction

Your air conditioning is only as strong as the ductwork delivering the cool air. Over time, ducts degrade, leak, or collect mold, sabotaging comfort and efficiency. A full ductwork replacement typically ranges from $2,000 to $5,000 for standard homes, but can exceed $10,000 for large or complex layouts. This guide gives you the cost factors, decision rules, and contractor vetting steps you need to plan a successful project.

Quick Answer: What Does AC Ductwork Replacement Cost?

On average, expect to pay $20–$40 per linear foot installed, including materials and labor. For a 150‑linear‑foot system (typical 2,000 sq ft home), that’s $3,000–$6,000. Material choice, accessibility, and region can shift the price. Get a personalized estimate with our HVAC Cost Estimator.

4 Warning Signs You Need New Ductwork

• Inconsistent temperatures: Some rooms are icy while others are warm, even with dampers fully open.
• Soaring energy bills: Leaky ducts force your AC to run longer to hit the thermostat set point.
• Excessive dust or musty smells: Holes in return ducts can pull attic dirt, insulation, or mold spores into living areas.
• Visible mold or collapsed sections: Mold inside ducts or crushed flex lines are health hazards that usually require replacement, not just cleaning.

Cost Factors That Shape Your Quote

Home Size & Layout

More square footage means more linear feet of duct. Multi‑story homes add vertical chases and fire‑rated assemblies, increasing labor.

Accessibility

Attic or basement installations are easier (and cheaper) than crawlspaces or tight closets. If drywall has to be cut for access, add $500–$1,500 for patching and painting.

Duct Material

Your choice affects both price and longevity. See the comparison below.

Total installed price, including labor, runs $20–$40 per linear foot for all types.

Permits & Disposal

Building permits ($50–$300) and hazardous material abatement (e.g., asbestos wrap on old ducts) can add $500–$2,000. Always verify with your contractor.

Repair or Replace? Decision Rules

Use these thresholds to decide:

• Age over 15 years → Replace. Modern ducts are better sealed and insulated.
• Multiple leaks (more than 3–4) or crushed sections → Replace. Leak sealing alone may not restore airflow.
• Mold inside ducts → Replace. Cleaning may not remove all spores; full removal is safer.
• Less than 10 years old with one or two small leaks → Repair. A professional duct sealing service often costs $300–$800.

Safety Boundaries: What You Can Check (and What to Leave to Pros)

Safe Homeowner Checks

• Visually inspect accessible ducts in attics or basements for disconnected joints or crushed sections.
• Feel for air leaks when the fan is running — hold a damp hand near joints.
• Check vents for excessive dust or mold around grilles.
• Listen for whistling or rattling that could indicate leaks.

Pro‑Only Work

Never attempt to: cut into ducts, remove sections, disturb insulation (may contain asbestos), work near gas lines, refrigerant piping, or electrical components. Any ductwork connected to a furnace, heat pump, or AC must be sealed by a qualified technician to avoid dangerous backdrafting or system damage.

Tools to Plan Your Ductwork Project

• HVAC Cost Estimator — Get a price range tailored to your home.
• Repair or Replace Calculator — Weigh the financial pros and cons.
• BTU Calculator — Ensure your new ductwork matches your system’s output.
• Rebate Finder — Many utilities offer incentives for duct sealing or replacement.

Contractor Checklist: 7 Questions to Ask

1. Are you licensed, bonded, and insured? Ask for proof and verify with your state’s licensing board.
2. Will you perform a Manual D calculation? Proper duct design ensures balanced airflow to every room.
3. What warranties do you offer? Look for at least 1‑year labor warranty and 5–10 years on materials.
4. Do you pull permits and schedule inspections? Never skip this step; it protects you if something goes wrong.
5. How will you protect my home? They should seal off work areas and clean up daily.
6. Can you provide a detailed, itemized quote? Avoid lump‑sum bids without a breakdown of materials, labor, and disposal.
7. Do you have references from similar projects? Call at least two recent customers to ask about punctuality, cleanup, and performance.

Local Market Considerations

• Hot/humid climates (Southeast, Gulf Coast): Insist on R‑8 or higher insulation and vapor barriers to prevent condensation and mold.
• Cold climates (Midwest, Northeast): Seal all joints tightly; condensation can freeze and cause ice dams or duct collapse.
• Coastal areas (salt air): Use aluminum or stainless‑steel rigid ducts to resist corrosion.
• Older homes (pre‑1980s): Budget for possible asbestos abatement and electrical upgrades. Find a contractor experienced with historic structures.

FAQs