What is Duct Sealing?
Plain-English explanation from a licensed Utah HVAC, plumbing, and electrical contractor.
Duct sealing closes the gaps, holes, and leaky joints in your duct system so the conditioned air your HVAC produces actually reaches the rooms instead of escaping into the attic or crawlspace.
Full Definition
Duct sealing is the practice of closing air leaks at duct joints, seams, and connections to mechanical equipment. Traditional method uses fiberglass mesh and mastic paste applied by hand. Modern aerosolized sealants (such as Aeroseal) are blown through pressurized ducts and self-deposit on leak edges, sealing holes up to 5/8 inch from the inside out. Properly sealed ducts pass a duct blaster test showing less than 4% leakage to outside.
Sealing 25% leaky ducts to under 5% leakage typically delivers 15–25% reduction in heating and cooling energy use plus immediate comfort improvement in rooms that previously wouldn't condition. Payback on a $1,500–$3,500 seal is usually 3–6 years.
Common Questions
Will sealing ducts help my hot upstairs room?
Often yes — if the supply duct serving that room is leaking conditioned air into the attic before it reaches the register, sealing recaptures it. About 60% of 'hot room' complaints in Utah are duct-related, not equipment-related.
Is duct sealing worth it on a new home?
Most production-built Utah homes from 2000–2020 weren't tested for duct tightness at construction. Many have 15–25% leakage even though they look 'new.' A simple seal often pays back fast.
Related Terms
Ductwork
Ductwork is the metal or flexible tubing system that carries conditioned air from your furnace or air handler to each room and returns it for re-conditioning.
Static Pressure
Static pressure is the resistance your blower has to push against to move air through the duct system — too high and the blower struggles, efficiency drops, and the system runs hot.
Recent HVAC work in Utah
A few installs and service calls from the AYSP crew.
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