Sealing helps when ducts are the right size but leak, especially in attics and crawlspaces. Redesign is needed when ducts are undersized, runs are too long, returns are missing, or rooms were added. A duct leakage test plus a static pressure test tells you which problem you have. Sealing typically costs $1,000 to $6,000.
Technical Consideration
Seal or redesign?
| Finding | Likely fix |
|---|---|
| High leakage, normal static pressure | Seal (mastic or Aeroseal) |
| Low leakage, high static pressure | Add returns or enlarge ducts |
| Disconnected or crushed flex duct | Repair and reroute |
| Rooms added with no ducts | Extend, add zone, or ductless |
| Ducts in hot attic | Seal, insulate, or relocate |
Published U.S. ranges for planning only, not Wilmington quotes. Your written price depends on diagnosis, access, equipment, permits, and timing. Sources: HomeGuide – air duct sealing cost.
What tests should be done?
A duct leakage test measures how much air escapes; static pressure shows whether the system can move enough air.
Pressure testing typically costs about $200 to $450.
Is Aeroseal a substitute for redesign?
No. Aeroseal closes leaks from inside the ducts but cannot fix undersized or badly routed ducts.
It is best for hidden leaks in walls and ceilings.
Are there rebates?
Energize Delaware lists duct sealing rebates of about $550 to $850 through Home Performance.
Confirm current program terms.
Related services in Wilmington
- Duct Sealing & Aeroseal in Wilmington, DE
- Ductwork & Airflow Services in Wilmington, DE
- Home Energy Assessments & Air Sealing in Wilmington, DE
Local verification resources
Before authorizing work, use the Delaware license lookup. For projects that may require approval, consult the City of Wilmington permit information or the authority serving the property.