Spiral duct typically costs $8-$20 per linear foot installed, while duct material alone runs about $2-$8 per foot for common galvanized steel sizes. Diameter, metal gauge, fittings, ceiling access, insulation, and local labor rates can move a project well above or below those ranges.
| Item | Low | Average | High | Notes |
|---|---|---|---|---|
| Galvanized duct material | $2/ft | $4/ft | $8/ft | Typical 6-12-inch diameter |
| Installed straight duct | $8/ft | $13/ft | $20/ft | Accessible commercial ceiling |
| Fittings and transitions | $15 each | $45 each | $120 each | Elbows, tees, reducers |
| Insulation, if required | $2/ft | $4/ft | $8/ft | Material and installation |
Installed spiral duct prices by diameter and project size
For a straightforward commercial installation, budget $8-$20 per linear foot for exposed spiral duct, including ordinary hangers and installation labor. A 100-foot run may total $800-$2,000 before unusual fittings, insulation, demolition, or controls. Material-only pricing is usually $2-$8 per foot, with larger diameters and heavier gauges at the upper end.
Those estimates assume galvanized steel, standard round duct, normal ceiling access, and no major structural changes. Stainless steel, painted finishes, high-pressure systems, or restricted access can increase the quote. Small jobs may also carry a contractor minimum that makes the effective per-foot rate higher.
A practical baseline is $13 per installed foot for a basic, accessible run. Assumptions: common galvanized steel, 6-12-inch diameter, standard fittings, typical U.S. commercial labor.
How duct, hangers, fittings, and labor shape the quote
Contractors may quote straight duct by the foot and list fittings separately, or provide a single installed rate. The breakdown helps reveal whether the estimate includes supports, cutting, sealing, delivery, and final connections. A low duct-only price is not comparable to a complete installed quote.
| Quote component | Typical price | What changes the charge | Common unit |
|---|---|---|---|
| Galvanized duct | $2-$8 | Diameter, gauge, finish | Per linear ft |
| Installation labor | $50-$100 | Crew skill, access, height | Per worker-hour |
| Hangers and supports | $3-$12 | Spacing and attachment type | Per support |
| Elbows, tees, reducers | $15-$120 | Shape, size, custom fabrication | Each |
| Delivery and disposal | $50-$300 | Distance and removed duct volume | Per job |
A crew billing at $50-$100 per worker-hour may take 10-20 hours to install a 100-foot run, depending on routing and access. Confirm whether the quote prices labor by the hour or includes it in the per-foot rate.
Diameter, gauge, and insulation thresholds that raise prices
Duct size strongly affects material and handling. A 6-10-inch run commonly falls near the lower material range, while 14-24-inch duct may cost $5-$15 per foot for material, depending on gauge and supplier. Runs above 24 inches often require heavier construction, larger supports, or lifts, so installed rates can exceed $20 per foot.
Metal thickness also matters: light-gauge duct may suit low-pressure applications, but specifications requiring 20- or 22-gauge steel can cost more than 24- or 26-gauge material. Insulation adds roughly $2-$8 per foot when condensation control, temperature retention, or code requirements call for it. Exterior runs may need weatherproof jacketing as well.
Check the specified diameter and gauge before comparing per-foot bids. The same footage can have substantially different pricing when the design pressure or support requirements change.
How ceiling height and labor hours affect installation price
Open ceilings and clear access keep installation closer to the low end. Work above 12 feet, congested mechanical spaces, occupied buildings, or night shifts can increase labor time and equipment charges. Lift rental may add $150-$500 per day, while difficult work may push labor toward $100-$150 per worker-hour in high-cost markets.
For planning, a two-person crew might install roughly 30-60 feet of simple exposed duct per day. Numerous elbows, branch connections, and tight turns reduce daily production. Ask the installer to state the assumed crew size, working height, and footage per shift.
Three sample spiral duct quotes for common runs
A 50-foot, 8-inch galvanized run in an open ceiling could cost $500-$1,000 installed, or about $10-$20 per foot. This assumes basic supports and a few fittings, with approximately 8-12 crew hours and no removal or insulation.
A 100-foot, 12-inch run with six elbows and two takeoffs might total $1,400-$2,600. Straight duct accounts for roughly $900-$1,700; fittings, supports, and extra labor add the rest. The effective rate is about $14-$26 per foot when accessories are included.
A 200-foot, 20-inch run with insulation and elevated access could reach $5,000-$9,000, or $25-$45 per foot. Larger material, lift use, added supports, and slower installation drive the higher total. These examples are budgeting ranges, not fixed bids.
Regional labor rates can shift the per-foot estimate
Urban markets with high wages and limited contractor availability may run 15%-35% above a national baseline. Rural areas can be 5%-20% below it, but travel fees and delivery minimums may erase part of that difference. The Northeast and West Coast often price higher than many Southern and Midwestern markets, especially for commercial work.
Local code requirements, union labor, building access rules, and material delivery distance also affect bids. Compare at least three estimates based on the same duct diameter, gauge, insulation, fitting count, and installation height. Regional averages are less useful than matching the job specifications line by line.
Lower the spiral duct bill by controlling fittings and scope
Keep the route direct where the mechanical design allows it. Every branch, transition, and direction change adds material and labor, while consolidating work into one mobilization can reduce minimum charges. If existing duct is serviceable, ask whether a repair or partial replacement can meet airflow and code requirements instead of replacing the full run.
Buyers can also compare galvanized steel with specified alternatives, but should not reduce gauge or omit insulation without approval from the designer or local authority. Schedule work during normal building hours and clear stored items from the work area before installation. Use a written scope to prevent unpriced fittings, access equipment, or disposal charges.
Removal, permits, and finish work that may sit outside the rate
Removing old duct may add $2-$6 per foot, with disposal or difficult ceiling access raising the charge. Painting exposed duct can add $2-$6 per foot, while custom color finishes may cost more. Permit fees vary widely, often from $100-$1,000 for commercial mechanical work, depending on jurisdiction and project scope.
Some projects require airflow testing, balancing, fire dampers, seismic bracing, or coordination with a fire-rated assembly. These are not necessarily included in a basic spiral-duct rate. Request separate prices for testing, permits, removal, painting, and code-related accessories.