Guides
Ductwork Cost per Linear Foot Insulated: US Price Breakdown
Ductwork cost per linear foot insulated runs $7 to $18 installed in US basements and attics, with labor near $3 per foot. See line-item splits and R-value effects.
What to take away
- Insulated round duct in the US commonly quotes between $7 and $18 per linear foot installed, with short branch runs at the low end and attic trunk lines at the high end.
- Material cost is usually 30 to 45 percent of the line item; labor, access, sealing and cleanup cover the rest.
- R-value changes the material priceR-4.2 and R-6 suit many conditioned basements, while R-8 is the working minimum for attic runs in cold climates.
- Short, complex jobs cost more per foot because the crew's setup, sealing and cleanup time is spread across fewer linear feet.
- Quotes often leave out access cuts, old duct disposal and failed tape or mastic until the job starts.
What the range covers
Insulated duct pricing looks simple until a contractor breaks out the bid. The illustrative US range for round insulated duct installed is $7 to $18 per linear foot. That spread accounts for duct diameter, insulation thickness, access, and whether the run is a main trunk or a short branch. Most jobs fall between $9 and $14 per foot when several runs are bundled. A single 6-foot repair in a finished attic can quote closer to $20 per foot because the crew still spends half a day on setup and cleanup. For a wider look at material differences, Flex Duct vs Metal Duct compares flexible and rigid options.
Line by line
A bid usually separates material, labor and extras. Use the table below as an illustrative per-foot split for an R-8 insulated round duct in a typical US attic.
| Line item | Low per linear foot | High per linear foot | Notes |
|---|---|---|---|
| Insulated duct material | $2.50 | $7.00 | R-6 and R-8 flexible or rigid round |
| Installation labor | $2.50 | $5.50 | Based on BLS median hourly wage for HVAC mechanics |
| Hangers, straps and fasteners | $0.60 | $2.00 | More on long horizontal runs |
| Sealing tape, mastic and fittings | $0.40 | $1.50 | Varies with joint count |
| Access, debris removal and cleanup | $1.00 | $2.00 | Higher in finished attics or crawlspaces |
| Total installed range | $7.00 | $18.00 | Short jobs skew high per foot |
The US Bureau of Labor Statistics lists a median hourly wage of $27.55 for heating, air conditioning and refrigeration mechanics and installers. That number feeds the labor column above, but actual crew rates vary by metro area from roughly $18 to $45 per hour once overhead and equipment are included.
What moves the number
Three cost drivers move the per-foot price more than anything else. First is R-value. Insulation thickness changes the material cost directly: R-4.2 duct in a conditioned basement might add $1 to $2 per foot over uninsulated flex, while R-8 attic duct can add $3 to $6 per foot. The thermal insulation article explains how resistance to heat flow rises with thickness. Second is diameter. A 6-inch round supply run often costs less than a 12-inch trunk because the larger duct uses more metal or foil and needs bigger hangers. Third is access. Crawlspace and attic runs that force a crew to work on ladders, over joists or around stored belongings can add 30 to 50 percent to the labor line. NFPA 90A sets installation and fire safety rules for air conditioning and ventilating systems, and some local inspectors require its insulation covering in attic plenums. NFPA 90A is the reference you will see on a permit note. For a line item view of sealing work, Duct Sealing Cost per Run separates tape, mastic and labor by run.
R-Value Cost Impact
R-4.2
- Typical location
- Conditioned basement
- Added cost per foot
- $1-$2
- Code fit
- Often meets code
R-8
- Typical location
- Unconditioned attic
- Added cost per foot
- $3-$6
- Code fit
- Needed in attics
Example: 40-foot attic trunk with three branch runs
A homeowner in a cold-climate state gets a quote for 40 feet of R-8 insulated round trunk in an unconditioned attic, plus three 12-foot branch runs. The material line might read $280 for the trunk at $7 per foot and $216 for branches at $6 per foot. Labor for two workers over one day might land near $640 at $40 per hour for eight hours each. Hangers, tape, mastic and a new plenum collar add another $180. The quoted total would be about $1,316, or $17.30 per linear foot across 76 feet. A second contractor might price the same work at $1,120 using R-6 branch runs and a smaller crew, which shows why comparing per-foot bids without R-value and diameter is a mistake.
What quotes leave out
But the invoice line items only tell part of the story. Missing items can raise the final bill by 15 to 25 percent. Here are three common gaps:
- Old duct disposal. A contractor may list removal separately at $60 to $150 for the truck run, and some bids exclude it entirely.
- Access cuts. Attic scuttle holes, drywall patches and crawlspace hatch weatherstripping can add $100 to $300 to a job.
- Failed tape or mastic. If the first sealing pass fails, a second trip costs $150 to $400, and that return visit rarely appears in the quoted price.
For a full bid sheet with markup and contingency, HVAC Contractor Business Job shows how a template handles those extra lines.
Where people overspend
Overspending usually comes from choosing the wrong R-value or the wrong diameter. Use this short check before you sign:
- Do not pay for R-8 on a basement run that only needs R-4.2.
- Do not replace an entire duct run when a single joint is leaking.
- Do not choose the largest diameter without checking static pressure or blower capacity. A common mistake is paying for R-8 throughout a conditioned basement where R-4.2 meets code. The extra insulation adds material cost and consumes clearance in tight joist bays.
Common questions
What R-value should I use for attic ductwork? R-8 is the common minimum for attic runs in cold US climates, but check local energy code. In milder climates R-6 may satisfy the inspector. Does the $7 to $18 per foot include the air handler? No, that range is for insulated duct material, labor, hangers, sealing and access. The air handler, condenser, thermostat and line set are separate line items. For cross-border pricing differences, US ductwork rates explains why material and labor prices shift across the border. Why is a short run so expensive per foot? Setup, travel and cleanup time are fixed costs. A 10-foot run carries the same mobilization as a 60-foot run, so the per-foot price rises on short jobs. Can I install insulated flex myself to save money? You can, but poor sealing can lose 20 to 30 percent of conditioned air. The time and materials you spend redoing it often erase the savings.
