First: there are two very different kinds of duct sealing
This trips a lot of people up. When a company quotes you thousands of dollars to “seal your ducts,” they almost always mean interior duct sealing — an aerosol process (you’ll hear the brand name Aeroseal) that sprays sticky sealant inside your duct system to plug leaks from within. That’s the expensive one. The other kind is exterior duct sealing — sealing the duct joints from the outside and insulating them. We do believe in duct sealing — the exterior kind, done where it actually matters. It’s the pricey interior / Aeroseal version we usually steer people away from. Here’s why.
Is Aeroseal (interior duct sealing) worth it? Usually not
Here’s what the sales pitch leaves out: in most homes the ductwork runs through interior ceilings and walls — inside your conditioned space. So even if a duct leaks a little, that heated or cooled air isn’t lost — it’s still going into the conditioned part of your home. You paid to temper that air, and you’re still getting it. Spending thousands to spray-seal those ducts from the inside usually changes very little, which is why Aeroseal isn’t worth it for the average home.
When duct sealing actually makes sense
There’s one real exception: ducts that run through an unconditioned space — an attic, a crawlspace, or an unfinished basement. Air that leaks out there is truly lost, because it escapes before it ever reaches the rooms you’re paying to heat and cool. In those homes, tightening up the ductwork genuinely pays off — but the right way to do it is far simpler and cheaper than an aerosol process like Aeroseal.
The smarter (and cheaper) way to seal those ducts
When ducts run through an attic or crawlspace, you don’t need a pricey aerosol process to seal them from the inside. We seal the duct joints from the outside by hand — right where the leaks are — then do the part interior sealing simply can’t: we insulate those ducts so they stop bleeding energy into a 130° attic or a freezing crawlspace. Sealing stops the leaks; insulating stops the bigger loss — heat soaking in and out through bare duct walls — and it usually costs far less than interior duct sealing. Why insulating attic & crawlspace ducts matters →
The test to ask for before you buy Aeroseal
This is the big one. Before you agree to interior duct sealing, ask for one number first: how much air actually comes out of your vents. A typical sales quote is built on a pressurized duct test that measures pressure loss — and they call that your “leakage.” But that number does not tell you what you actually lose when the vents are open and the system is running. It’s a pressure test, not a real-world airflow test.
We do it the right way: we measure the true airflow (CFM) coming off your system and out of your vents — so we can tell you exactly how many CFM you’re really losing, not a scary-sounding pressure number on a sales sheet.
How much does Aeroseal / duct sealing cost — and does it actually work?
Interior duct sealing like Aeroseal often runs well into the thousands. That’s a lot for a fix that, in most interior-duct homes, barely moves the needle. Does it actually work? In the right situation — ducts in unconditioned space, with real measured losses — sealing helps. But you almost always have cheaper, more effective options first: cleaning a clogged blower and coil, swapping a too-restrictive filter, balancing your airflow, or sealing and insulating attic ducts from the outside. Don’t pay thousands until someone has actually measured your losses.
Get a straight answer first
Before you spend thousands, get the facts. We’ll come out, measure the real airflow (CFM) coming off your system, see exactly where your ducts run, and tell you straight whether sealing is worth it for your home — and if it is, the smartest, most affordable way to do it. A clear diagnosis and a fair price. Book an airflow measurement → or call 801-960-5925.
Measure first, then decide
Send us your quote or book an airflow measurement — we’ll tell you what your ducts are really losing.