Ductwork replacement cost
Updated 2026-11-07 · By the HVAC Service Estimator team
Ductwork is the line item that catches homeowners out, because the equipment prices you have been reading do not include it. Angi's 2026 gas furnace range of $3,800 to $10,000 explicitly excludes ductwork, gas line work and the thermostat. We do not have a national figure for duct replacement that we trust, so this page does not invent one. Instead it explains how duct work is measured and priced, why a contractor who wants to touch your ducts may be doing you a favor, and what to demand in a local quote.
Why there is no price range on this page
We publish specific figures where our sources support them. Angi's 2026 guide gives a gas furnace at $3,800 to $10,000 and a full system average of about $7,500. Trane publishes $5,093 to $5,481 for an 80% single-stage furnace. 2026 guides put central AC replacement at $3,900 to $7,900. All of those appear elsewhere on this site with the source named.
None of them covers ductwork. Angi, in fact, goes out of its way to say its furnace range excludes it. That exclusion is the real content here: duct work is a separate scope with its own price, and the reason no useful national average exists is that duct jobs are not comparable to each other. Replacing an accessible trunk and six branches in an open basement, and rebuilding a duct system buried in finished ceilings on two floors, are different trades-worth of work at the same square footage.
What a duct quote is built from
| Line item | Type | What moves it |
|---|---|---|
| Supply and return trunks | Material | Sheet metal vs duct board; size and length; fabrication |
| Branch runs | Material | Count, length, and rigid metal vs insulated flex |
| Plenums and the equipment transition | Material plus labor | Custom-fabricated to the new furnace, air handler or coil |
| Boots, registers and grilles | Material | Count, size, and whether existing openings can be reused |
| Return air path | Material plus labor | Undersized returns are the most common defect, and adding one is real construction |
| Dampers and balancing hardware | Material | Needed if the system is to be balanced at all |
| Sealing and insulation | Material plus labor | Mastic and tape at every joint; insulation value where ducts run outside conditioned space |
| Demolition and disposal | Labor | Removing old ducts; vastly more if asbestos-containing material is present |
| Access and repair | Labor | Opening and patching drywall, ceilings, soffits - sometimes a separate trade |
| Permit and inspection | Fee | Mechanical permit, commonly required |
| Design and balancing | Labor | Manual J load, Manual D duct design, and post-install airflow measurement |
Two rows deserve attention. Access and repair is why the same duct layout costs wildly different amounts in a basement and in a finished two-story house. Design and balancing is the row most often missing from a cheap quote, and its absence is the reason some brand-new duct systems perform no better than the ones they replaced.
The measurement that should drive the decision
Before anyone recommends replacing ducts, someone should put a manometer on the air handler and read total external static pressure, then compare it to the pressure the blower is rated for. That single reading tells you whether the duct system can move the air the equipment needs.
It matters financially because of what high static does. A blower fighting excessive resistance cannot deliver its rated CFM. Low airflow across the evaporator coil means poor cooling, low suction pressure, and ice - symptoms that look exactly like a low refrigerant charge. That is how homeowners end up paying for refrigerant their system never lost: Angi prices a recharge at $100 to $500, and a technician who adds refrigerant to a system that was actually starved for airflow has both overcharged it and left the real problem in place. See refrigerant leak repair cost for how a proper diagnosis distinguishes the two.
Low airflow also shortens equipment life, which puts duct problems upstream of the expensive failures. A compressor flooded with liquid refrigerant because the coil is starved is a compressor you will replace early - and Angi puts that at $800 to $3,000, with Homeyou's 2026 data averaging $2,487. See AC compressor replacement cost.
Repair, seal, or replace
Sealing and targeted repair
Usually the best value. Leaks concentrate at joints, at boot connections and at the plenum. Mastic on those joints, reconnecting or straightening flex runs that have pulled off, been crushed or kinked, and insulating duct running through an unconditioned attic or crawl space will recover most of the lost performance of a tired but sound system.
Partial replacement
Often the right compromise: replace the trunk and the returns, which are where the undersizing and the biggest leaks usually live, and keep the branch runs that are intact and correctly sized.
Full replacement
Justified when the ducts are physically failing - crushed, disconnected, water-damaged, rodent-contaminated - when asbestos-containing material has to be abated anyway, or when the layout cannot deliver the airflow the new equipment needs no matter how well it is sealed. That last case is a design conclusion, which means it should come with a Manual D duct design, not a hunch.
Design: Manual J, then Manual D
Duct design follows load calculation. A Manual J establishes how much heating and cooling each room needs; a Manual D sizes the trunks and branches to deliver the matching airflow at a static pressure the blower can actually produce. Skip the first and you size ducts for the wrong loads. Skip the second and you get a duct system that is new but no better proportioned than the old one.
Insist that the load calculation be confirmed for your house rather than inherited from the old equipment's nameplate, and never accept sizing done from photographs. If you are replacing equipment at the same time - see furnace replacement cost and AC replacement cost - this is the moment when the load calculation does double duty, because the equipment and the ducts are being matched to the same numbers.
One climate-specific point: if you are moving to a heat pump, ducts matter more than they did. Heat pumps deliver heat at a lower supply temperature than a gas furnace, so they must move more air to move the same heat. A duct system that was marginal behind a furnace can be plainly inadequate behind a heat pump.
Commissioning: proving the new ducts work
A duct job is finished when it has been measured, not when the last register goes on. Ask for:
- Total external static pressure after the work, compared against the blower's rating
- Measured blower airflow, against the CFM the equipment needs for its capacity
- Room-by-room airflow readings at the registers, and dampers balanced to match the Manual J loads
- A duct leakage test where the jurisdiction or the scope calls for one
- Temperature split across the coil, and superheat and subcooling to confirm the charge against the corrected airflow
- A combustion analysis on a gas furnace in the same system
- All of it written on a startup sheet and handed over
Getting comparable quotes
With no benchmark number to check against, scope comparison is your only protection. Require each bidder to state in writing: the static pressure they measured, what they propose to replace versus seal, the duct material and sizes, whether a Manual J and Manual D are included, who patches drywall and ceilings, whether the permit is included, and what they will measure afterward. With HVAC Service Estimator HVAC+ you can itemize trunk, branches, boots and registers, sealing, demolition, access repair and permit at local rates, which makes it obvious when one bid has quietly excluded the drywall patching or the balancing. An app estimate is informational - on duct work especially, the walkthrough and the manometer reading are what produce a real number.
Frequently asked questions
Why does this page not give a dollar range for ductwork?
Because the price research behind this site has no duct figure we are willing to publish. Our sources - Angi, Fixr, Trane, This Old House - give specific current numbers for furnaces, central AC, heat pumps, capacitors, refrigerant leaks and compressors, and those appear elsewhere on this site with attribution. Duct replacement varies so much by house that even if a national average existed it would tell you little: the same square footage can mean an accessible basement trunk or a full rebuild through finished walls. Get local quotes and compare them on scope.
Is ductwork included in a furnace or AC replacement quote?
Usually not, and Angi says so explicitly - its $3,800 to $10,000 gas furnace range excludes ductwork. Expect a changeout quote to include the sheet metal transition at the equipment, the plenum and the connections, and to exclude the branch runs, registers and returns unless it says otherwise in writing. This is the single most common reason two quotes for 'the same job' differ by thousands.
How do I know if my ducts are the problem?
By measurement, not opinion. The key number is total external static pressure, read across the air handler with a manometer and compared to the pressure the blower is rated for. High static means the blower is fighting the duct system and cannot deliver its rated airflow, which shows up as poor cooling, uneven rooms and shortened equipment life. A contractor who measures static pressure and shows you the reading is giving you evidence. One who diagnoses your ducts by looking at them is guessing.
Can ducts be repaired instead of replaced?
Often, and it is usually the better value. Sealing leaks at joints and boots, repairing crushed or disconnected flex runs, adding insulation on ducts in unconditioned attics or crawl spaces, and correcting one badly undersized return can fix most of the performance problem for far less than a rebuild. Full replacement makes sense when the ducts are failing physically, when asbestos or serious contamination is present, or when the system layout is fundamentally wrong for the equipment you are installing.
Sources
- Angi - Insider's price guide to a new heating and cooling system (2026)
- Trane - Pricing guide
- Fixr - Central air conditioner repair cost (2026)
- This Old House - Air conditioner repair cost
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