Professional air duct sealing costs a national average of $2,250, with most homeowners paying $500 to $4,000, according to Angi (updated October 2026)1. HomeGuide prices the job at $1 to $2 per square foot, or $1,000 to $6,000 in total (updated October 2025)2. Fixr puts sealing a duct system at $1,000 to $3,000, with lower prices when only a small section needs sealing (updated August 2025)3. The publishers scope their figures differently, so figures are labeled separately throughout this guide.
Cost by home size
Angi prices duct sealing at $0.50 to $1.50 per square foot of home, averaging around $1 per square foot (2026)1. HomeGuide publishes $1 to $2 per square foot (2025)2. These are separately published figures with different dates, and no conclusion about which rate applies follows from the difference. Angi's size figures (2026)1:
| Home size (sq. ft.) | Angi duct sealing cost, per project (2026) |
|---|---|
| 1,000 | $500 – $1,500 |
| 1,500 | $750 – $2,250 |
| 2,000 | $1,000 – $3,000 |
| 2,500 | $1,250 – $3,750 |
| 3,000 | $1,500 – $4,500 |
HomeGuide's size figures at its higher rate (2025)2:
| Home size (sq. ft.) | HomeGuide average total cost, per project (2025) |
|---|---|
| 1,000 | $1,000 – $2,000 |
| 1,500 | $1,500 – $3,000 |
| 2,000 | $2,000 – $4,000 |
| 2,500 | $2,500 – $5,000 |
| 3,000 | $3,000 – $6,000 |
Manual vs. aerosol sealing
Manual sealing applies metal tape or mastic directly to leaks and suits large holes and gaps; aerosol sealing sprays sealant into the system to seal small leaks from inside the ducts21. Angi puts manual sealing at an average of $2,250 and aerosol sealing at $1,300, and notes aerosol works for minor leaks only (2026)1. HomeGuide prices the Aeroseal brand aerosol system at $1,500 to $6,900, and notes gaps larger than 5/8 inch – or disconnected or blocked ducts – require manual sealing instead (2025)2. These figures carry different scopes – generic aerosol versus a specific brand system – and no conclusion about which applies follows from the differences. Fixr adds that sealing costs are lower when only a small section or one or two main ducts need work rather than the whole system (2025)3.
Leak count also drives the total: Angi prices accessible supply-vent leaks at around $50 each and leaks behind walls, under floors, or in attics at $50 to $100 or more per leak (2026)1.
When ducts need repair first
Ducts in poor condition often need repairs before sealing. Angi puts ductwork repair at an average of $660, ranging from $200 to $2,100 (2026)1. Fixr publishes a national repair average of $600 – typically repairing a leaky section and applying sealant – with a range of $200 to $1,000, and its repair figures by problem, based on a standard 1,500-square-foot home (2025)3:
| Duct problem | Fixr repair cost, per project (2025) |
|---|---|
| Broken vent | $100 – $250 |
| Loose sections | $100 – $500 |
| Hole | $150 – $350 |
| Rust | $150 – $500 |
| Clog | $200 – $500 |
| Condensation | $200 – $1,000 |
| Leak | $350 – $650 |
| Rodents | $450 – $2,000 |
| Collapsed section | $500 – $2,500 |
| Mold removal | $2,000 – $6,000 |
Where damage is extensive, HomeGuide puts full or partial ductwork replacement at $25 to $55 per linear foot, or $1,400 to $5,600 total (2025)2; Fixr puts replacing an average section at $250 to $3,000 (2025)3. See our ductwork installation cost guide for new-install pricing.
Inspection and pressure testing
Inspection figures differ by publisher: Angi puts a duct inspection at around $150 (2026)1, HomeGuide at $150 to $500 including the furnace and AC unit (2025)2, and Fixr at $75 to $175, noting some companies waive the fee when hired for the repair (2025)3. These are separately published figures with different scopes, and no conclusion about which applies follows from the differences.
For pressure testing after sealing, Angi and HomeGuide each publish $200 to $450 – identical ranges. The identical numbers do not establish that the priced services are the same, and the pages state no shared sourcing, so the match alone does not establish independent corroboration12.
Labor and related services
Fixr puts ductwork contractor labor at $75 to $200 per hour, with minimum fees around $100 and call-out fees of $75 to $100 that may be waived when hired (2025)3. HomeGuide puts related HVAC repairs at $75 to $150 per hour (2025)2. Angi states that labor accounts for around 90 percent of its average $2,000 manual sealing total, with materials the remaining 10 percent (2026)1. For related work, Fixr prices duct cleaning at $350 to $1,000 and duct insulation at $1,000 to $2,500 (2025)3, while HomeGuide puts duct insulation at $1 to $13 per square foot (2025)2 – separately published figures with different units and scopes. See our air duct cleaning cost guide for more on cleaning.
Signs of leaking ducts and hiring a pro
Signs the publishers list for leaking ducts include higher utility bills without another explanation, uneven heating or cooling between rooms, stuffy rooms, and musty odors13. All three publishers recommend professional sealing: Angi notes that locating leaks without professional equipment is difficult and that labor makes up most of the cost (2026)1, and HomeGuide advises confirming whether quotes include inspection and pressure testing (2025)2.
Related guides
Ductwork Repair Cost
See our guides to air duct cleaning cost, ductwork installation cost, HVAC repair cost, and HVAC installation cost.