DATA-BACKED GUIDE · UPDATED JULY 2026
How Much Does Ductwork Replacement Cost?
Ductwork is the least glamorous line on any HVAC quote and one of the most expensive to redo. It is a big labor job, since crews are crawling through attics and walls running sheet metal or flex duct. Prices land in four or five figures depending on the size of the home and how much is accessible. It is often bundled with a system install, which is both convenient and a place where the total gets fuzzy. Here is what drives it.
The quick version
- Ductwork is mostly labor, so home size and how accessible the runs are drive the price.
- Replacing ducts during a system install shares labor and access, which usually saves money.
- Leaky or undersized ducts waste the efficiency you paid for in a new system.
- A quote that bundles ducts into a system total can hide what the duct work actually costs.
- Sealing existing ducts is sometimes enough, and far cheaper than a full replacement.
Published and surveyed prices
Why the price varies so much
Duct pricing is about labor and access more than materials. A single-story home with an open crawlspace or basement is straightforward, while a two-story house that needs ducts fished through finished walls is not. The size of the home sets the linear footage, and whether you use rigid sheet metal or flexible duct changes both cost and performance. Ductwork is usually cheapest when it rides along with a central AC install, a furnace install, or a heat pump install, since the crew already has the system open and the attic accessed. Region and contractor markup fill in the rest.
How to pay less
- Ask whether sealing and repairing existing ducts would do the job instead of a full replacement.
- If you are replacing the system anyway, bundle the duct work so the crew only sets up once.
- Get the duct work itemized separately from the equipment so you can see what you are paying for.
- Ask for a duct-sizing calc, since oversized new ducts are wasted money and undersized ones choke airflow.
- Check for utility rebates on duct sealing, which some energy programs cover.
- Get more than one quote, since duct labor estimates vary widely between contractors.
Common questions
Do I really need new ductwork?
Not always. If ducts are just leaky at the joints, sealing them is far cheaper than replacing them. Full replacement is warranted when ducts are badly undersized, crushed, moldy, or so old they are falling apart. A duct-leakage test tells you which situation you are in.
Why is ductwork so expensive?
It is a labor-heavy custom job, since every home's runs are different and much of the work happens in tight attics and crawlspaces. There is no off-the-shelf duct kit that just drops in. The materials are modest, but the hours and the access are what you are paying for.
Should I replace ducts when I replace the system?
Often yes, because the crew is already there with the system open, so you save on setup and access. Pairing new ducts with a central AC install or a heat pump install also means the new equipment gets the airflow it was sized for. Get the ducts itemized so you can still judge that piece on its own.
What's the difference between sealing and replacing?
Sealing closes the leaks at joints and seams with mastic or specialized methods, keeping your existing ducts. Replacing tears them out and installs new ones. Sealing is much cheaper and fixes most leakage problems, while replacement is for ducts that are the wrong size or physically shot.
Can bad ducts hurt my new AC?
Yes. Leaky or undersized ducts dump conditioned air into your attic and starve the system of airflow, which wastes the efficiency you paid a premium for. You can install a top-tier unit and still get mediocre comfort and high bills if the ducts are the weak link.