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Seal leaky air ducts
Trigger
As needed / energy audit finding
Who does it
DIY or Pro
Est. time
2-4 hrs
Est. cost
$50-300
Difficulty
●●●○○
Step by step
Inspect accessible ducts in the attic, basement, or crawlspace for gaps at joints.
Clean the duct surface where you'll apply sealant.
Seal seams with mastic sealant or foil (UL-181) tape - never cloth duct tape.
Insulate ducts running through unconditioned spaces.
For hidden/hard-to-reach ducts, hire a pro for a duct-sealing service (aeroseal).
Questions to ask your pro
- Will you use Aeroseal pressurized spray or hand-applied mastic, and which is more effective for my duct layout?
- Can you perform a duct blaster test before and after to quantify the leakage reduction?
- Will you seal both supply and return ducts?
- Are there sections of ductwork too deteriorated to seal that need full replacement?
- Will the work include insulating ducts that run through unconditioned spaces?
- Can I qualify for a utility rebate for duct sealing, and will you provide documentation?
Video guide
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Bill of materials