Ductwork Installation Cost Calculator

Ductwork Material Cost Comparison

What switching material actually costs you

This calculator's own dataset prices a new whole-home install at $2,400–$5,000 for flex up to $4,000–$8,000 for sheet metal — material roughly doubling the total. An independent source, Fixr, publishes per-linear-foot rates for a duct replacement job instead (material, labor, and removing the old duct — a more inclusive scope than this page's new-install headline, so read the two side by side rather than as the same number). On Fixr's own stated basis of 275 linear feet for a 2,500 sq ft home:

• Flexible fiberglass, uninsulated: $6.95–$28.95/ft × 275 ft = $1,911–$7,961
• Galvanized spiral: $9.06–$37.14/ft × 275 ft = $2,492–$10,214
• Galvanized sheet metal: $21.38–$62.36/ft × 275 ft = $5,880–$17,149

Two different sources, two different job scopes, and the same direction of travel: sheet metal runs roughly two to three times flex on identical footage in both. That consistency, not either total alone, is the real cost consequence of the material choice — pick by what the job needs (tight, twisting access favors flex; a long service life and better airflow favor sheet metal), because the gap between a new install and a full replacement of the same material dwarfs the gap between materials within either one.

What moves the price

• Home size & runs. More square footage and more registers mean more linear feet of duct, which raises the total.
• Access. An open basement or unfinished attic is cheapest; tight crawl spaces or finished walls add 20–40% in labor.
• Material. Flexible duct is cheapest; rigid sheet metal costs more but lasts 25+ years and moves air better.
• New vs. retrofit. Roughing duct into new construction is far cheaper than snaking it into an existing finished house.
• Zoning & returns. Extra returns and zone dampers improve comfort but add cost.

Repair, seal, or replace?

Deciding whether to repair or replace ductwork usually comes down to leakage: in a typical house, 20–30% of the air moving through the duct system is lost to leaks, holes and poorly connected joints — per ENERGY STAR — but you often don't need a full replacement to fix that. Consider the cheaper fix first:

• Manual seal (mastic/tape): $1–$2 per sq ft, or $1,000–$6,000 total depending on home size — the cheapest fix for accessible leaks, per HomeGuide.
• Aeroseal: $1,500–$6,900, per HomeGuide — an aerosolized sealant sprayed through the system from the inside, reaching leaks manual sealing can't. It only works on gaps up to 5/8"; wider gaps, or disconnected or blocked sections, need manual sealing or a real repair instead.
• Inspection or pressure test first: a duct inspection runs $150–$500 and a nitrogen pressure test $200–$450, per HomeGuide — cheap relative to either sealing method, and the only way to know which gaps you actually have before paying to fix them.
• Replace: when duct is crushed, disconnected, mold-laden, or asbestos-wrapped regardless of age, or once the system is old enough that sealing is a stopgap — commonly around 15–20 years for the flex duct most retrofit systems use, per Today's Homeowner, which matches the flex-duct service life cited below rather than adding a new number.

Read those two facts together and the decision is arithmetic, not guesswork: sealing tops out around $6,900 even at the Aeroseal end, against $2,400–$8,000 for this page's own new-install headline and roughly $2,400–$5,000–$4,000–$8,000 to replace an existing system outright. Sealing beats replacement on cost whenever the ducts themselves are sound and the problem really is leakage — which the inspection or pressure test above is what actually tells you, rather than age or guesswork. Replacement wins once the duct itself has failed, because no amount of sealing fixes a crushed run or a section an inspector won't certify.

If the furnace or AC is also due — not just the ducts feeding them — pricing the two separately understates the job; see the furnace + AC replacement calculator for a whole-system estimate instead of a ductwork-only one. And if the room in question is an addition, a converted garage, or anywhere the existing trunk line doesn't reach, running new duct to it is not the only option — a ductless mini-split conditions that one room without any of the duct work priced above.

Duct material types

• Flexible (flex): insulated plastic-and-wire tube — cheapest and fast, but kinks and sags if installed poorly. Lasts 15–20 years.
• Sheet metal: galvanized steel — durable (25+ years), best airflow, resists mold; costs the most and is labor-intensive.
• Fiberboard: insulated on the inside (quiet), good for low-pressure systems, but can shed fibers over time.

Sizing done right

Duct that's too small starves the system (noisy, weak airflow, short equipment life); too big and it can't maintain velocity. A proper job uses a Manual D duct design paired with the Manual J load calc for the equipment. If a contractor just reuses the old layout without measuring static pressure, treat it as a red flag. Sizing duct and sizing the furnace or AC it feeds are the same conversation — price the whole system with the HVAC installation cost calculator before locking in a duct design, since undersized duct is often what makes an otherwise correctly sized system underperform.

Questions to ask — and red flags

Ask:

• Will you do a Manual D design and measure static pressure?
• What material, and is sealing/insulation included?
• Is my old duct wrap tested for asbestos (pre-1980 homes)?
• Is the quote itemized, with permits and patching noted?

Red flags:

• All-flex duct with long, sagging runs.
• No sealing or static-pressure test.
• Reusing the old layout without measuring.
• Disturbing suspect (vermiculite/tape) insulation without testing.

Warranty: get a written workmanship warranty (typically 1–2 years) on the install, and confirm that any duct materials and sealants carry their own manufacturer warranty.

What's included — and what's extra

Frequently asked questions