Reviewed July 22, 2026
HVAC Rescue Editorial Team
Editorial StandardsTypical cost ranges
General national ranges for orientation only — your quote depends on the specifics.
Patch a single hole or reconnect a joint
Per-repair pricing on accessible ducts; most companies also charge a service-call or diagnostic fee
$167 – $617
Targeted leak sealing (mastic and foil tape)
Hand-sealing leaks at accessible joints, boots, and plenum connections
$300 – $1,250
Whole-house manual duct sealing
Every accessible joint sealed with mastic or UL 181 foil tape; typical for an average-size home
$1,050 – $4,150
Aeroseal (aerosolized interior sealing)
Seals leaks from inside the ducts, including runs you can't reach; large or complex homes can exceed $6,000
$1,800 – $5,250
Replace one crushed or damaged branch run
Removing and re-running a single flex-duct branch, including materials and labor
$388 – $963
Attic or crawlspace repairs with difficult access
Tight crawlspaces, deep attics, and rodent or moisture damage push labor time up
$800 – $3,850
What affects the price
Where the ducts run
Ducts in an open basement are the cheapest to fix; attic and crawlspace work costs more in labor time, and ducts buried in finished walls or ceilings add drywall cutting and patching on top of the duct work itself.
Number and size of leaks
One disconnected boot is a quick fix, but duct systems rarely leak in just one place — a full-system sealing job costs several times more than a spot repair because every joint gets treated.
Sealing method
Manual mastic-and-tape sealing is typically a fraction of the price of Aeroseal, but it only reaches leaks the crew can see and touch; aerosolized sealing costs more and treats the whole system from the inside.
Duct material
Flex duct is cheap to replace but easy to damage; sheet metal costs more per foot to fabricate and repair; older fiberboard (duct board) that is degrading often can't be meaningfully repaired at all.
Diagnostic testing
A formal duct-leakage (pressure) test typically adds a few hundred dollars but measures exactly how much air the system loses, which helps you size the fix instead of guessing.
Insulation condition
If duct insulation is crushed, wet, or chewed by rodents, re-wrapping the repaired runs adds material and labor — and skipping it in an unconditioned attic or crawlspace gives back part of the energy savings.
Local labor rates
The same two-hour repair can differ by hundreds of dollars between a high-cost coastal metro and a lower-cost Midwestern or Southern market.
Age of the home and system
Homes built before roughly 1980 may have asbestos-containing duct wrap or tape, which requires testing and licensed abatement before anyone disturbs it — a separate cost from the duct repair itself.
What a duct repair quote usually includes line by line
A real duct repair quote should break the job into diagnosis, repair method, materials, and access time. For a small repair, that often means a service call or diagnostic fee, locating the leak or disconnected joint, cleaning the surface so sealant will stick, then sealing with mastic and UL 181 foil tape or reconnecting the run with screws, clamps, and hanger strap. If a flex branch is crushed or torn, the quote may show removal of the damaged section and a new insulated flex run. In many markets, that kind of spot repair lands in the same general range as a single accessible patch or one branch-run replacement, but it varies by access and travel.
Whole-house duct sealing quotes should read differently because they cover more labor. You should expect to see supply and return trunks, branch takeoffs, boot connections, plenum seams, and air-handler connections listed as areas to be sealed, plus whether insulation is being pulled back and reinstalled in the attic or crawlspace. Aeroseal proposals usually separate setup, sealing, and before-and-after leakage testing, because the equipment and process are different from hand sealing. If a quote just says 'seal ducts' with one lump sum and no method, ask for a clearer scope before comparing numbers.
Common exclusions matter because they change the final bill. Drywall cutting and patching for ducts buried in walls or ceilings is often excluded from an HVAC quote, as are mold remediation, rodent cleanup, new boots or grilles unless listed, and asbestos testing or abatement on older duct wrap or tape. Electrical repairs for a failed blower or control issue are separate from fixing leaks in the duct system, and so is replacing a furnace, air handler, or evaporator coil. A low quote sometimes looks low simply because those items are left out.
Why two duct repair quotes can differ by hundreds or thousands
Two contractors can look at the same attic and reach different prices without either one being dishonest. One may be quoting a targeted repair at the obvious disconnected boot and a few visible seams, while another is pricing a full-system sealing job because they expect multiple leaks at the plenum, return box, and branch connections. Manual mastic sealing and aerosolized interior sealing are not equivalent scopes. A quote in the several-hundred-dollar range for accessible hand sealing is not directly comparable to a whole-house Aeroseal quote in the low-thousands, even though both are described as 'duct sealing. '
Labor time drives a lot of the spread. Open basement ductwork is straightforward; a low attic with buried flex duct, tight crawlspace, or rodent-damaged insulation can turn a half-day repair into a much longer job. Material also changes the approach. A short flex-duct branch can be replaced fairly cheaply, while damaged sheet-metal sections may need fabrication, and deteriorated duct board may not hold a durable patch at all. In a high-cost metro, the same repair can legitimately price well above a lower-cost market simply because labor, insurance, and travel time cost more.
Red flags are less about the dollar amount and more about the missing details. Be cautious if a quote calls for cloth 'duct tape' instead of mastic or UL 181 foil tape, skips fastening methods on flex duct, or promises to seal hidden leaks without saying whether the method is manual or aerosolized. Another warning sign is a contractor quoting major duct repair without inspecting the full run or asking where comfort problems show up. On the other side, an expensive quote is not automatically better if it bundles equipment replacement when the problem is really disconnected or leaking ducts.
What makes the price climb: access, house layout, insulation, and testing
The location of the ducts changes the bill more than many homeowners expect. Repairs in an unfinished basement are usually the least expensive because the crew can see and reach the joints. In attics, labor rises because workers often have to move insulation, build temporary walk paths, and work around trusses in high heat. Crawlspaces add their own time because of tight clearances and ground moisture. If the damaged section sits above a finished ceiling or inside a soffit, the duct repair itself may be only part of the project once opening and restoring finishes are added by others.
Home layout also matters. A compact one-story house with short duct runs is faster to diagnose and seal than a large two-story home with multiple trunks, long branch runs, and separate return paths. If the system has many supply boots, multiple plenums, or older additions tied in at different times, crews spend more time tracing leaks and deciding what is worth sealing versus replacing. Wet, crushed, or rodent-chewed insulation on the ducts adds cost too, because repaired runs in an unconditioned attic or crawlspace usually need new insulation wrap to avoid giving back part of the energy savings.
Testing can raise the upfront price but sharpen the repair scope. A formal duct leakage test often adds a few hundred dollars as an estimate, yet it can tell you whether the system has a minor localized problem or broad leakage that justifies whole-house sealing. Aeroseal jobs commonly include before-and-after leakage measurements because proving the reduction is part of the value. If one quote includes testing and another is based only on visual inspection, the tested quote may look higher at first while actually being the more precise way to avoid under- or over-repairing the ducts.
How to lower the cost without accepting sloppy duct work
The easiest way to control duct repair cost is to make the work accessible before anyone arrives. Clear storage away from the attic hatch, crawlspace door, basement trunk lines, and mechanical room so the crew does not spend paid time moving boxes. If you know certain rooms have weak airflow or you have seen a loose duct in the attic, note those locations in advance. A focused inspection can save time, though a careful contractor should still check the rest of the accessible system because ducts rarely leak in only one place.
Ask each bidder to price the same scope in writing: spot repair only, targeted manual sealing, or whole-house sealing. That lets you compare like with like instead of judging one number against another vague number. If accessible leaks are limited to a few joints and one damaged branch run, hand sealing and a short replacement may be the sensible estimate. If the ducts disappear under insulation or behind finishes and comfort problems are house-wide, paying for testing or an interior aerosol-sealing option can be the better apples-to-apples comparison.
You can also save money by handling non-HVAC prep separately where appropriate. For example, if the only reason a duct cannot be reached is a small access panel or ceiling cut, some homeowners arrange the drywall opening and patching with a general contractor instead of having the HVAC company coordinate it. What usually does not save money is choosing the cheapest patching material or skipping insulation replacement on repaired attic ducts. The callback risk and lost efficiency often erase the initial savings.
When the higher duct-repair price is the cheaper decision over time
Spending more now often makes sense when the choice is between repeated spot patches and a more complete sealing job. If a house has one obvious disconnected run plus many leaking trunk seams and return connections, fixing only the visible break may restore one room while leaving the blower to keep losing conditioned air into the attic or crawlspace. In that situation, a broader manual sealing job or a tested whole-house approach can cost more upfront but reduce wasted runtime for years. Over a five- to ten-year window, fewer callbacks and lower utility waste can easily outweigh the smaller initial ticket.
Paying more can also be smarter when the damaged duct material will not hold a durable repair. Older flex duct with brittle inner liner, water-damaged insulation, or degraded duct board often looks patchable until it is handled. Replacing one bad branch run for a few hundred dollars as an estimate may be cheaper long-term than repeatedly taping tears that reopen. The same logic applies if hanging straps failed and the duct is kinked or crushed; restoring full airflow usually means re-running that section, not just sealing around the damage.
The expensive option is not automatically the right one. Aeroseal is usually the premium path and can be worthwhile where many leaks are hidden or inaccessible, but it is often unnecessary if the system is exposed and most leaks can be reached by hand for far less. Likewise, a formal leakage test is useful when the scope is uncertain, while it may not pencil out for a single visible disconnected boot in an open basement. The cheaper decision over time is the one that matches the actual duct problem, not the fanciest method on the menu.
Estimate methodology
How we built these ranges
We compare current national project-cost reporting with the technical scope of this job, then keep materially different scopes separate instead of presenting one misleading average. This page was reviewed on July 22, 2026.
The ranges account for factors such as where the ducts run, number and size of leaks, sealing method, duct material. They are planning figures, not a local quote. Equipment capacity, model, warranty status, access, labor, permits, code upgrades, and related electrical or duct work can move an actual proposal outside them.
Compare written, itemized proposals for the same model numbers and scope. Ask whether diagnosis, labor, refrigerant, permits, disposal, warranty registration, and any required supporting work are included.
Sources and fact-checking
Reviewed July 22, 2026. We favor primary government and standards sources for safety, efficiency, and regulatory claims. Published project-cost sources are used for national planning ranges and are cross-checked against the scope described above.
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