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Ductwork is one of those things customers never think about until something goes wrong. They call about uneven temperatures or high energy bills, and suddenly you're quoting a partial or full duct replacement that costs more than they expected. Getting the pricing right matters both for your margins and for setting honest expectations.
I've priced ductwork jobs from single-room additions to complete systems in 3,500 sq ft homes. The numbers vary a lot depending on material, accessibility, and whether you're working in new construction or retrofitting an existing house. Here's how it all breaks down.
Material costs per linear foot
| Duct type | Material cost/linear ft | Installed cost/linear ft |
|---|---|---|
| Sheet metal (galvanized, rectangular) | $3.00-$7.00 | $12.00-$25.00 |
| Sheet metal (round/spiral) | $2.50-$5.50 | $10.00-$20.00 |
| Flexible duct (insulated) | $1.00-$3.00 | $5.00-$12.00 |
| Fiberboard duct | $1.50-$4.00 | $7.00-$15.00 |
| Duct board (rigid fiberglass) | $2.00-$4.50 | $8.00-$16.00 |
Sheet metal is the gold standard. It lasts decades, handles airflow well, and doesn't sag or restrict over time. Flex duct is cheaper and faster to install, which is why it dominates residential new construction in many markets. But flex duct installed poorly (kinked, too long, unsupported) creates airflow problems that come back to haunt you on callbacks.
My general rule: use sheet metal for trunk lines and main runs, flex for branch runs to individual registers. That balances cost, performance, and installation speed.
Whole-system pricing
For a complete duct system, here's where the numbers land:
| Home size | Linear feet of duct (approx) | New construction | Retrofit / replacement |
|---|---|---|---|
| 1,200-1,500 sq ft | 150-250 | $2,500-$5,000 | $4,000-$8,000 |
| 1,500-2,000 sq ft | 200-350 | $3,500-$7,000 | $5,500-$11,000 |
| 2,000-2,500 sq ft | 300-450 | $5,000-$9,500 | $7,500-$15,000 |
| 2,500-3,500 sq ft | 400-600 | $7,000-$13,000 | $10,000-$20,000 |
The retrofit column is 50-80% higher than new construction because you're working around existing structures. Cutting through joists, running duct through tight attic spaces, and patching drywall all add labor hours.
Why new construction and retrofit are different animals
In new construction, you install ductwork before the drywall goes up. You can see the framing, plan your routes, and hang duct without obstruction. A two-person crew can rough in a complete duct system for a 2,000 sq ft house in 2-3 days.
Retrofit work is a different story. You're in the attic, in the crawl space, or cutting soffits. Access dictates everything. I once spent four hours just getting a 10-foot section of trunk line into a finished basement because the only access was through a 24-inch utility chase. That kind of thing doesn't show up when you're estimating from the driveway.
For retrofit jobs, I always do a site inspection that includes going into the attic or crawl space. If I can't physically see where the duct needs to go, I'm not bidding it.
Labor breakdown
HVAC sheet metal installers run $55-$95/hour depending on your market (check the contractor rate lookup). Helpers are $30-$45/hour. Most duct installations use a two-person crew.
Time estimates by task:
- Trunk line installation: 15-25 linear feet per hour (sheet metal)
- Branch runs (flex): 30-50 linear feet per hour
- Register boots and transitions: 20-30 minutes each
- Plenum fabrication and installation: 2-4 hours
- Sealing and testing: 2-4 hours for a complete system
For a 2,000 sq ft house with about 300 feet of ductwork, figure 30-50 total labor hours for new construction, 45-75 for retrofit.
The components people forget to price
Ductwork isn't just pipe. There's a list of components that add up, and missing them on a bid eats your margin fast:
- Supply plenum: $150-$400 (fabricated sheet metal)
- Return plenum: $150-$350
- Register boots (each): $15-$40
- Dampers (each): $15-$35
- Takeoff collars (each): $8-$20
- Duct tape and mastic: $50-$120 per system
- Insulation wrap (if attic/unconditioned space): $0.50-$1.50/sq ft of duct surface
- Hangers and strapping: $75-$200 per system
- Return air grilles and supply registers: $12-$45 each
On a typical 2,000 sq ft house, these components add $800-$1,800 to your material cost. That's money you can't recover if it's not in the bid.
Partial duct replacement and additions
Not every job is a full system. Common partial jobs include:
| Job type | Typical price range |
|---|---|
| Add duct run to new room (addition) | $500-$1,500 |
| Replace trunk line only | $1,200-$3,500 |
| Replace all flex runs (keep trunk) | $1,500-$4,000 |
| Add return air drop | $300-$800 |
| Duct sealing (aerosol or manual) | $800-$2,500 |
| Zoning system (dampers + controls) | $1,800-$4,500 |
Partial replacements are where you need to be careful about scope creep. You open up a section of duct and find the adjacent run is in worse shape. Have a change-order process ready before you start cutting.
How to quote ductwork profitably
Do a Manual D calculation (or use your load calc software) to size the system properly. Undersized ductwork causes noise, poor airflow, and callbacks. Oversized ductwork wastes material and money. Getting it right the first time is cheaper than fixing it later.
Measure actual runs, don't estimate from the floor plan. Floor plans don't show joist direction, obstacle locations, or the 4-inch water pipe that's exactly where your trunk line needs to go. Walk the space and measure.
Quote sheet metal trunk lines even if the builder wants all flex. Explain why (better airflow, lasts longer, fewer callbacks). If they still want all flex, that's their call, but you've set the expectation.
Include duct sealing in every bid. Mastic on all joints should be standard, not optional. Leaky ductwork wastes 20-30% of conditioned air, and you'll take the blame for comfort complaints even if the leaks are at the joints you didn't seal.
Use the HVAC pricing calculator to verify your margins before submitting the bid. Ductwork bids are easy to underprice because there are so many small components.
Margins to target
New construction ductwork: 35-45% gross margin. The work is predictable, access is easy, and you can schedule efficiently.
Retrofit ductwork: 45-55% gross margin. The higher margin accounts for the unknowns, the access challenges, and the slower installation pace. Don't let customers compare your retrofit price to a new construction number. They're different jobs.
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