How to Quote a Ductwork Replacement Job | Reddit & LinkedIn

Three things drive duct replacement cost: total run length, material type, and access. Sheet metal trunk with insulated branch runs costs more than all-flex, but it seals better and holds up in hot attics. Access is the hidden cost. A one-story home with a walkable attic prices very differently from a tight crawlspace or a two-story with duct chases.

Most residential systems need 120 to 260 linear feet of duct across supply and return. At $9 to $22 per linear foot installed depending on material and access, that is where the $3,400 to $9,600 range comes from. Add $45 to $120 per register and boot.

Insulated flex duct runs $9 to $16 per linear foot installed and is fast to hang, which keeps labor down on branch runs. Rigid sheet metal runs $14 to $28 per linear foot installed, takes longer to fabricate and hang, and is the right call for trunk lines and any run that needs to stay clean and rigid.

Most quotes mix both: sheet metal trunk and takeoffs, insulated flex on the branch runs. Price each material as its own line so the client sees why a sheet metal trunk costs more than an all-flex bid from the shop down the road.

A single-story home with attic access runs 16 to 28 labor hours for a two-person crew. A two-story or a crawlspace job runs 24 to 44 hours because every run is a fight. Add hours for asbestos-era duct removal, tight chases, and any structural blocking that has to come out.

Do not flat-rate duct by the foot alone. Two 180-foot jobs can differ by 15 labor hours based on access. Walk the space before you quote, and set your labor line off the real hours, not a per-foot shortcut.

Snap photos in the attic, type or speak the runs and diameters, and the AI drafts labor and material line items using your own rates, never invented numbers. Every line shows where its price came from, your template or an AI estimate, so you can trust the draft before you send it.

You build the full itemized bid in about 25 minutes instead of a couple hours at the kitchen table, then send a link the client accepts on their phone. Once accepted, the job runs in one workspace with tasks, photos, and milestone payments.

Duct callbacks come from leaks and bad airflow, not the shingle-count math. Seal every joint with mastic, not cloth tape that dries out and lets air escape into the attic. Support long runs so flex does not sag and choke airflow. After the install, take a static pressure reading and adjust the balancing dampers so every room gets its share.

Note these steps on the quote as part of the scope. A client comparing your bid to a cheaper one should see that you are pricing a sealed, balanced system, not just hanging pipe. That is also how you protect your labor warranty, because a duct system that leaks or whistles is a callback you do not get paid for.