How Can I Seal a Leaking Air Duct to Improve HVAC Efficiency?

Seal small duct leaks with HVAC mastic or UL-181 foil tape after cleaning the joint; avoid cloth duct tape. In Denver and Thornton homes, this simple fix can improve airflow and comfort. For large tears or collapsed sections, schedule professional repair or replacement.

• Find leaks with smoke or feel for air while system runs.
• Clean and dry metal or flex duct surface.
• Brush on mastic or apply UL-181 foil tape to seams.
• Recheck airflow; insulate sealed sections.

Regular maintenance catches hidden duct issues early; same-day service is available.

Updated: 2025-12-21

Need help in Thornton, CO? Call (720) 994-7055 or book online.

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