One bedroom in the back of the house never gets cold, no matter where you set the thermostat. The power bill keeps climbing. The system runs and runs. Somewhere in that story there’s usually leaking ductwork, and the first question I get once I say so is always the same: does that mean opening up the walls? Usually not. There’s a way to fix duct leaks from inside the ducts themselves.
Sealing From Inside the Duct System
We block off every register and return grille, hook equipment to the duct system, and pressurize it. A polymer sealant goes in as a fine aerosol mist and rides the moving air. Wherever air escapes through a seam or a pinhole, those particles pile up at the edge of the opening and gradually bridge it shut.
It’s a little like sealing a slow tire leak from the inside instead of pulling the tire off the rim. Not a perfect comparison, but close enough.
That’s what lets us fix duct leaks buried above a finished ceiling in a Ballantyne two-story, where the trunk line runs through a chase nobody’s touched since the house was framed. I’ve had homeowners brace themselves for drywall dust, then watch the whole thing happen from a hallway return grille.
What Aeroseal Can and Can’t Handle
Joints, seams, connections, pinholes, gaps around boots that’s the sweet spot. Anything roughly the width of a pencil eraser or smaller usually closes up.
What Aeroseal won’t do is put a duct back together. I pulled a crawl space hatch off a house near Steele Creek last spring and found a flex run lying in the dirt, disconnected at the plenum, six inches of open air. No mist is bridging that. Same story for flex crushed under storage boxes or torn open by something living down there.
So sometimes we do both. Hand-seal or replace the ugly stuff first, then fix duct leaks throughout the rest of the system with aeroseal. Anybody who tells you one method covers every house hasn’t crawled under enough of them.
Why Charlotte Ductwork Leaks in the First Place
Half the homes I work in around Charlotte have ductwork sitting in a vented crawl space or an unconditioned attic. In July that attic hits 130 degrees. Your air handler pushes 55-degree air through sheet metal and flex sitting in that oven, and every gap along the way dumps cooled air where nobody lives.
Return-side leaks are worse down in the crawl. Those pull humid, musty air straight into the system, which is a big reason older houses in Dilworth and Plaza Midwood start smelling like the crawl space by mid-August.
Mastic dries out. Cloth-backed tape turns to powder. Sheet metal joints work loose after twenty years of the blower cycling. Nothing fails dramatically it just gets quietly worse until somebody finally decides to fix duct leaks and learns the system was losing a quarter of its air.
What the Appointment Actually Looks Like
Testing comes first, always. We measure how much the system is leaking before we fix duct leaks, because that number tells you whether the work is worth doing at all.
Most single-system homes run three to five hours start to finish. Two systems, plan on the better part of a day. You’ll want to be out of the way furniture near the registers gets covered and the equipment isn’t quiet.
The part homeowners like is the numbers. We take a leakage reading before, watch it drop live during, and take another after. You’re not taking my word that it worked.
One more thing: new construction in Mecklenburg County already has to pass a duct leakage test before it gets a certificate of occupancy. This is the same measurement, just run on a house that’s long past that inspection.
Get the Ducts Tested Before You Guess
Every month you wait, you’re paying to condition an attic. And a roll of foil tape on the two feet of duct you can actually reach won’t fix duct leaks in the parts of the system you’ll never see. Call Dependaworthy One Hour Heating and Air and start with a leakage test. Dependable + Trustworthy = DEPENDAWORTHY!
FAQ
Will they have to cut into my walls?
Almost never for the sealing itself. The mist travels through ductwork you already have, so hidden seams get sealed without access. If we find a collapsed or disconnected section, that part may need hands-on repair.
Can this fix duct leaks in old flex ductwork?
Often, yes if the flex is intact. Aged flex with a brittle inner liner or torn insulation jacket sometimes needs replacing instead. We’ll tell you which one you’ve got before charging you for sealing that won’t hold.
How long does the seal last?
The manufacturer backs it for years, and I’ve gone back into houses I sealed and seen the readings hold. What shortens it is movement ducts getting stepped on in the attic or bumped during a remodel.
Will it lower my power bill?
If leakage is significant, usually yes. How much depends on your equipment, insulation, and habits, so I won’t quote you a percentage. Tight ducts mean the air you paid to cool reaches the room instead of the crawl space.
My house is only ten years old could it really be leaking?
Absolutely. Plenty of newer Huntersville and Waxhaw builds passed their leakage test on day one, then had joints work loose over a decade of Carolina summers. Age helps, but it doesn’t exempt anybody.
Test before you seal. If your ducts turn out tight, we’ll say so and you can go chase the real problem.
