HVAC Ductwork Cost Guide 2026

Quick Answer: HVAC ductwork commonly runs $5 to $25 per linear foot as of 2026, depending on type, size, and whether it is insulated. The price is set mostly by sheet metal gauge, duct dimensions, and the type of system, with freight playing a larger role than on smaller materials. Treat the ranges below as a planning anchor and pull live quotes from your supplier for the actual bid.

What Drives the Price

Ductwork is the air distribution network for an HVAC system, built from galvanized steel, aluminum, or flexible polymer, and it carries supply air, return air, and exhaust. It is priced by the linear foot but the unit cost swings widely by type. Six variables drive almost all of the cost:

Material: Galvanized steel (G90) is the default for commercial and most residential trunk and branch ducts. Aluminum is used for corrosion resistance and weight savings, typically 2 to 3 times the price of steel. Flex duct (flexible polymer over a wire helix) is the cheapest, used for short branch runs.
Type and shape: Rectangular galvanized ducts are built from sheet stock on a duct shop, priced by the linear foot of fabricated duct. Spiral ducts are round, factory formed, and carry a premium for appearance and lower leakage. Round pipe ducts are cheaper than spiral but plainer. Flex duct is the cheapest option per foot.
Size: Duct cost scales with perimeter. A 6 in round flex run costs a fraction of a 24 in by 12 in rectangular trunk. Bigger ducts use more sheet metal per foot and cost more.
Insulation: Bare duct is cheapest. Externally wrapped or internally lined duct adds 30 to 60 percent to the price per foot. Acoustical lining for noise control adds more. Thermal insulation for energy code compliance is often required and adds to the line item.
Fittings and accessories: Elbows, transitions, takeoffs, registers, grilles, dampers, and hangers are separate lines that can equal the cost of the straight duct. Fittings are priced each, not per foot.

Steel commodity index and freight are the market drivers. Sheet steel moves with the domestic steel market, and duct is bulky enough that pallet and truckload freight is a real cost on commercial jobs.

Typical Price Ranges by Type

These are commonly quoted ranges as of 2026, per linear foot, fabricated and delivered. Fittings and accessories are priced each and listed separately.

Flex duct, 4 in to 6 in (insulated): $2.50 to $5.00 per LF
Flex duct, 6 in to 10 in (insulated): $4.00 to $8.00 per LF
Round pipe, 6 in to 8 in, galvanized: $5.00 to $9.00 per LF
Round pipe, 10 in to 14 in, galvanized: $8.00 to $14.00 per LF
Rectangular galvanized, 8 in by 12 in: $7.00 to $12.00 per LF
Rectangular galvanized, 12 in by 18 in: $10.00 to $16.00 per LF
Rectangular galvanized, 20 in by 24 in: $15.00 to $25.00 per LF
Spiral duct, 8 in to 12 in: $10.00 to $18.00 per LF
Spiral duct, 16 in to 24 in: $18.00 to $30.00 per LF
Aluminum duct (any size): 2 to 3 times the galvanized price
Internally lined duct (any size): add 30 to 60 percent over bare

Fittings are priced each: a 90 degree elbow runs $15 to $80 by size and type, a transition runs $20 to $100, a takeoff runs $8 to $30. Dampers and volume control boxes run $40 to $250 each. Hangers run $2 to $10 per foot installed.

How to Calculate the Quantity You Need

Take duct lengths off the mechanical plans, by type (rectangular, round, spiral, flex) and by size. For each run, measure from the air handler or trunk to the register, following the routed path on the plans. Add the vertical rises: air handler to ceiling, ceiling to register, and any soffit drops. Duct runs are not straight, so add the fittings. Each elbow, transition, and takeoff is a separate fitting counted on the fitting line.

Apply a 5 to 10 percent waste factor on top of the measured length. Galvanized duct is cut from sheet stock, and offcuts are usually too short to reuse. Flex duct is cut to length at the takeoff and the leftover is usually too short to reuse.

Round up to the buy unit. Galvanized sheet is sold by the sheet (4 ft by 8 ft or 4 ft by 10 ft). Pre fabricated ducts are sold by the section (typically 4 ft or 5 ft). Flex duct is sold by the box (25 ft or 50 ft). If a run calls for 32 ft of 6 in flex, you buy one 50 ft box and the leftover becomes waste on the next run. Track each duct type and size on its own takeoff line.

Count fittings on a separate line. Every duct run has at least one elbow at the takeoff and one at the register, plus transitions and takeoffs at the trunk. Fittings can equal the cost of the straight duct on a complex job.

How to Buy Smarter

Pull three quotes on bid day. Sheet metal pricing is less volatile than copper but distributors still quote off different cost bases. A 10 to 25 percent spread on the same size is normal.
Buy pre fabricated sections when you can. Factory ducts are cheaper per foot than shop fabricated, and they ship faster. Shop fabricated is needed for odd sizes and custom transitions, but standard sizes should be factory.
Bundle the duct package. Buying ducts, fittings, dampers, registers, and grilles from one supplier in a negotiated package usually beats line item shopping, and it gives you one backorder to manage.
Match the type to the spec. If the spec calls for spiral duct, do not substitute rectangular or flex to save money without a written RFI response. The wrong type fails inspection and voids the leakage test.
Plan the insulation line. Energy code often requires insulation on supply and return ducts in unconditioned spaces. Price insulation as a separate line so it is not eaten by the bare duct unit cost.

Where Estimators Get It Wrong

The most common mistake is pricing the straight duct and forgetting the fittings. A duct run is the section plus elbows, transitions, takeoffs, dampers, and registers. Fittings can equal the cost of the straight duct on a complex job, and missing them turns a profitable bid into a loss.

The second is missing the vertical rises. Estimators measure along the plan view and forget the air handler to ceiling rise, the ceiling to register drop, and the soffit drops. On a two story building these rises can add 15 to 25 percent to the duct quantity.

The third is ignoring the insulation line. If the bare duct unit cost looks low, check whether insulation is included. Often it is not, and the missing insulation line can swing the duct package by 30 to 60 percent.

The fourth is undercounting hangers. Ducts need to be hung every 8 to 12 ft per code, and hangers are a separate line item. A big job can have thousands of hangers, and missing them eats the labor budget.

Putting It Together

Price ductwork by the linear foot, by type and size, off a measured takeoff that includes vertical rises, bends, and a 5 to 10 percent waste factor. Count fittings, dampers, and hangers on separate lines. Reprice duct on bid day from three suppliers, buy pre fabricated sections where you can, and bundle the duct package with the fittings. Read the spec for type and insulation requirements before you commit.