Duct sealing cost
Sealing leaky ducts costs $400 to $1,900 with manual methods (mastic and foil tape) and $1,300 to $2,700 with Aeroseal, which seals leaks from the inside. A duct leakage test costs $250 to $400.
Quick answer
$400 – $2,700manual sealing to Aeroseal
Duct sealing costs $400 to $2,700 for most homes. A leakage test alone starts at $250; extensive whole-system sealing by duct-cleaning companies can reach $6,000.
Cost by method
| Method | Cost | Best for |
|---|---|---|
| Manual (mastic, foil tape) | $400 – $1,900 | Accessible ducts in attics and basements; large gaps |
| Aeroseal (internal aerosol) | $1,300 – $2,700 | Hidden ducts; cracks up to about 5/8 inch |
| Duct leakage test | $250 – $400 | Measuring leaks before and after |
| Duct insulation | $800 – $2,000 | Ducts in hot attics or cold crawl spaces |
Why seal your ducts
According to the U.S. Department of Energy, about 20% to 30% of the air moving through a typical home's ducts is lost to leaks, holes and poorly connected sections. Sealing can improve comfort in far rooms, reduce dust and lower heating and cooling bills, especially when ducts run through unconditioned attics or crawl spaces.
Manual vs. Aeroseal
Manual sealing works well for ducts you can reach. Aeroseal is better for ducts behind walls and ceilings and comes with before-and-after leakage numbers. If ducts are crushed, disconnected or very old, replacement may be the better fix.
How to get a fair quote
- Get at least three written quotes that list the brand, model number, size (tons or BTU) and efficiency rating.
- Ask whether the price includes permits, removal of the old unit, refrigerant, a new thermostat and any duct or electrical work.
- Ask for a load calculation (Manual J) instead of matching the old unit's size by default.
- Compare labor warranties (1 to 10 years) as well as the manufacturer's parts warranty, and register the equipment.
- Schedule non-urgent work in spring or fall, when contractors are less busy and more willing to discount.
Frequently asked questions
How much does duct sealing cost?
About $400 to $1,900 for manual sealing and $1,300 to $2,700 for Aeroseal.
Is duct sealing worth it?
Usually, if ducts run through unconditioned spaces or a leakage test shows high losses. It often pays back through lower energy bills and better comfort.
How long does Aeroseal last?
The sealant is rated to last decades; manufacturers commonly offer 10-year warranties.
Sources
Prices are national averages and typical ranges from published cost data. Your price depends on your home, region, equipment and contractor, so get several written quotes. Heat & Air Costs is not an HVAC contractor; read our disclaimer.