Compare duct sealing and replacement quotes side by side so you can spot the lowest upfront price and missing scope items.
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Table of contents
How to use our Duct Sealing vs Duct Replacement Cost Calculator
- Choose the items that match What did the inspection find?; select only Not inspected yet if you do not have inspection details.
- Enter at least two positive quotes in the four price fields, leaving any option blank if it was not priced.
- Open Advanced options to add a consistent Planning range around each price and record whether restoration and duct-leakage testing are included.
- Click Calculate and read Repair options to examine from the selected findings before treating the lowest price as your preferred project.
- Sanity-check each quote against Proposal scope items to confirm, especially whether wall repair, testing, removal, insulation, and finish work are actually included.
Definitions
Manual duct sealing: Sealing reachable duct joints, seams, boots, and connections with approved materials such as mastic or approved tape.
Aerosol duct sealing: A duct-sealing service that uses an aerosol sealant process; it should be priced separately from manual sealing unless a proposal clearly combines them.
Targeted duct replacement: Replacing only named duct runs, branches, or damaged sections instead of the entire duct system.
Full duct replacement: Replacing the whole duct system covered by the contractor's proposal.
Planning range: A user-chosen percentage added below and above each entered price for budgeting. It is not a statistical confidence range or a promised final price.
Duct-leakage testing: A test that measures duct air leakage before work, after work, or both; proposals may include different test stages.
Common mistakes and quick fixes
Mistake: Entering $0 for an option that was not quoted in Manual duct sealing price.
Fix: Leave an unpriced option blank. The calculator omits blank options from the comparison.
Mistake: Combining manual sealing and aerosol work in Aerosol duct sealing price without checking the proposal.
Fix: Keep Manual duct sealing price and Aerosol duct sealing price separate unless the contractor gives one clearly combined price.
Mistake: Selecting Not inspected yet along with a condition in What did the inspection find?
Fix: Choose Not inspected yet only when no finding is known; otherwise select the actual reported findings.
Mistake: Treating the Planning range around each price as a contractor guarantee.
Fix: Use it only as your own equal planning spread around every entered price.
Mistake: Comparing Full duct replacement price with a sealing quote that excludes different work.
Fix: Check Wall or ceiling repair in the prices and Duct-leakage testing in the prices, then ask about other exclusions before comparing prices.
Limitations & Key Assumptions / Boundary Conditions
- This tool compares only the upfront prices you enter. It does not estimate local market prices, energy savings, payback, utility bills, or financing costs.
- At least two positive option prices are needed. A blank price is omitted, while zero and negative prices are invalid.
- The planning range applies the same percentage above and below every entered price. It does not account for different contractor risks or hidden conditions.
- Condition guidance is a screening aid, not a duct diagnosis. Moisture, mold, pests, or contamination concerns need qualified inspection before work is chosen.
- Sealing can address leakage, but it does not by itself correct ducts that are undersized or poorly laid out.
- Scope controls only change the reminder text. They do not add costs for wall repair, testing, permits, insulation, removal, balancing, registers, or finish work.
Methodology
Price comparison
The calculator uses every nonblank, positive entered price. It requires at least two prices, then finds the least expensive entered center price. Blank options do not count as $0.
included costs = all nonblank option costs greater than $0
lowest entered upfront cost = smallest included cost
If full replacement has a valid price, the calculator compares it with the lowest entered option. If full replacement is already tied for the lowest price, its extra cost is shown as $0.
extra cost of full replacement = full duct replacement price - lowest entered upfront cost
Planning range
The optional percentage applies equally to each entered option. For example, a Manual duct sealing price of $1,800 with a Planning range around each price of 10% displays $1,620 low, $1,800 entered, and $1,980 high.
planning low = option price x (1 - planning range / 100)
planning high = option price x (1 + planning range / 100)
Condition and scope checks
Leaks at joints or vents point toward reviewing sealing quotes. Damaged sections add targeted replacement to the comparison. A sizing or layout concern adds replacement and duct-design review because sealing alone does not change duct size or routing. A moisture, mold, pest, or contamination concern leads to inspection-first guidance. The scope note uses Wall or ceiling repair in the prices and Duct-leakage testing in the prices only as comparison reminders; it does not change any dollar amount.
Calculation boundaries
Prices come from your quotes or planning figures, so results are a quote comparison rather than a market estimate. The calculator cannot determine hidden damage, needed duct design changes, or which contractor scope is complete without proposal details and inspection evidence.