How much does it cost to install ductwork?
A whole-house duct installation costs $2,000 to $6,000 in a home with accessible attic, basement, or open framing, and figures out to roughly $10 to $25 per linear foot installed for standard flex or sheet-metal runs. A typical single-family home needs 100 to 200 feet of duct, plus a supply and return register in most rooms. Adding just one new run to feed a single room or a finished addition costs $250 to $1,000 depending on how far the air handler is and how hard the path is to reach.
Per-register pricing is the other way installers quote the job. Expect $300 to $600 per vent for a supply run with its boot, grille, and the branch duct back to the trunk line. Returns cost a little more because they are larger. The plenum (the sealed box on the air handler that feeds the trunks) and the main return drop add several hundred dollars each if they are being built new rather than reused. If you are pricing ducts as part of a bigger project, size the equipment first with the BTU calculator so the duct system is matched to the airflow it actually has to move.
How much does it cost to add ductwork to a house that has none?
Retrofitting ducts into a finished house that never had them is the expensive case: $6,000 to $15,000 or more for the ductwork alone, and that is before the furnace, air handler, or AC. Homes heated by hot-water baseboard, radiators, or electric wall units have no chases for ducts, so the crew has to open walls, ceilings, and closets, run the trunks and branches, then patch and repaint everything they cut. The drywall and finish work is often a third of the bill.
The layout of the house decides how bad it gets. A two-story home with no attic access to the first floor is the worst case, because the first-floor supplies usually have to come up from a basement or down through built-out soffits and chases. Older balloon-framed homes sometimes offer stud and joist cavities that make hidden runs easier, but every house is different. In a lot of these homes the honest math points away from ducts entirely: a ductless mini split system skips the demolition and is often thousands cheaper, which is the tradeoff laid out in mini split vs central air.
What drives the cost of a ductwork installation?
Access is the single biggest cost lever. Open framing in new construction or a walk-in basement is quick; ducts buried in finished walls, tight crawl spaces, or a low attic take far longer and cost more, and anything that means opening drywall adds patch-and-paint on top. Home size and story count multiply from there: more square footage means more linear feet and more registers, and a second floor almost always needs its own runs routed to it.
Material matters less than people expect but still moves the number. Flexible duct is the cheapest and fastest to install; sheet metal costs more per foot but lasts 20-plus years and flows air better on long runs; fiberglass duct board sits in between and adds some insulation. A good installer mixes them, using rigid metal for the main trunks and flex for short branch connections. The last driver is design: a proper system is sized from a Manual D calculation matched to the equipment, and skipping that is how you end up with weak rooms no thermostat can fix.
Two smaller line items round out the bill. Most jurisdictions require a mechanical permit for new ductwork, which runs $50 to $400 and is folded into a licensed contractor's price. And sealing the new joints with mastic before they are hidden is cheap insurance against the 20 to 30 percent of air a leaky system wastes; the right way to do it is covered in duct mastic sealant.
Can you install HVAC ductwork yourself?
Some of it, yes. Adding a single accessible flex run to a nearby room, extending a duct into a new closet or addition, or building a return in an open basement are within reach for a careful DIYer, and the materials are cheap. Work in the cool part of the day if you are in the attic, watch your footing on the joists, and wear a mask and gloves around sheet metal and fiberglass. Sealing every joint with mastic as you go is the part homeowners most often skip and most benefit from.
A whole-house system is a different job. Trunk and branch sizing comes from a Manual D calculation, and a layout that just guesses at duct sizes is the most common reason a brand-new system underperforms. New ductwork also usually needs a mechanical permit and an inspection, and tying the ducts into a gas furnace or a mains-voltage air handler is licensed, permitted work for good reason. For the full-system picture, see how much it costs to install HVAC. Do the accessible runs yourself if you like, and hire out the design, the equipment tie-in, and anything behind finished drywall.
Is installing new ductwork worth it, or is ductless cheaper?
New ductwork is worth it when you already have forced-air equipment and the ducts are missing, undersized, or too far gone to repair, or when you are building and can run them into open framing cheaply. In those cases a tight, correctly sized duct system delivers even temperatures and lets the equipment hit its rated efficiency. If your ducts merely leak or have a few failures rather than being absent, repairing and sealing them is far cheaper than a fresh install; those numbers are in ductwork repair and replacement cost.
Ductless is usually cheaper when you are starting from no ducts in a finished home. A one-zone mini split installs in a day with just a three-inch hole through the wall, and even a multi-zone system that covers a whole house often beats the cost of demolishing and rebuilding to hide ducts. Ductless also lets you condition only the rooms you use and skips the 20 to 30 percent duct loss entirely. The full side-by-side, including where central air still wins, is in mini split vs central air.
Frequently asked questions
How much does it cost to replace ductwork in a 2000 sq ft house?
Replacing the ducts in a 2,000 sq ft house typically costs $3,000 to $8,000, since that size home usually has 150 to 250 linear feet of duct at $25 to $55 per foot installed. Easy attic or basement access lands near the low end; ducts buried in finished walls and ceilings push toward the top. Replacing existing ducts is cheaper than a from-scratch retrofit because the chases and register openings already exist. See our full breakdown of ductwork repair and replacement cost.
Why is ductwork so expensive?
Ductwork is expensive because it is mostly labor in awkward places. A crew spends hours fabricating and hanging metal or flex in hot attics, tight crawl spaces, and finished walls, and any run hidden behind drywall means cutting and patching afterward. On top of that, a proper system is engineered with a Manual D calculation, sealed, insulated, and permitted. The materials are cheap; the access, the labor, and the finish work are what you are paying for.
Should I replace 20 year old ductwork?
Often yes, if the ducts are leaking badly, rusted or rotted, moldy inside, or clearly undersized for the system. Sheet metal ducts last about 20 to 25 years and flex duct 15 to 20 before the liner and insulation break down, so 20-year-old ducts are near the end of their life. A 20-year-old system with only one or two specific failures is still worth repairing and sealing instead of a full replacement.
Can I install my own HVAC ductwork?
You can install accessible pieces yourself, like adding a single flex run to a nearby room or building a return in an open basement, and sealing your own joints with mastic is genuinely useful. A whole-house system is a pro job: the duct sizing comes from a Manual D calculation, the work usually needs a mechanical permit and inspection, and connecting to a gas furnace or a mains-voltage air handler is licensed work. Do the easy runs, hire out the design and the equipment tie-in.
How long does it take to install ductwork?
A whole-house duct install in an accessible home takes 2 to 4 days for a typical crew. A single new run or register is often a half-day job. A full retrofit into a finished house with no existing ducts takes a week or more once you count opening walls and ceilings, running the system, and doing the drywall and paint repair afterward.