Key takeaways
- Seams and connections are the usual leaks
- Return leaks pull dusty air into the house
- Sealing comes before insulating
- Mastic beats tape
Where leaks hide
Ducts leak at seams, at the boot where a duct meets a register, at connections to the equipment and where flex ducts attach to rigid ones. Over time, hot attics dry out tape and joints separate.
Even small gaps add up across a whole system.
What leaks cost you
Leaked supply air heats or cools the attic instead of the room. Leaked returns pull attic or crawl space air into the system. Both make the equipment run longer and leave rooms uneven or dusty.
Our Duct Leak Lab shows the impact of different leak levels.
The fix
Seal seams and connections with mastic, replace damaged sections and then insulate exposed ducts. Sealing before insulating makes the insulation work.
A follow-up airflow check confirms the result.
Related services
Quick answers
How much air do leaky ducts lose?
It varies a lot. Studies of typical homes find significant losses. A test or inspection shows your own.
Can I seal ducts myself?
Accessible joints can be sealed with mastic, but hidden ducts and big repairs need a professional.
Ready to talk it through? Get a free estimate or call 615-431-3789.