Duct Repair & Service in Southern Illinois

When Half Your House Won't Heat or Cool No Matter What You Do

Is one bedroom always freezing while the rest of the house is fine, or are you hearing a metallic bang from the ceiling every time the furnace kicks on? Are you seeing dust puff out of your vents even though you just changed the filter, or has your energy bill doubled with no change in how you use the house? These aren't quirks you live with — they're signs your ductwork is failing, and every day you wait costs you more in wasted energy and equipment wear. Smith Heating, Air & Sheet Metal has been chasing duct leaks, crushed flex runs, and disconnected joints across Southern Illinois for decades, and we're ready to find what's wrong and fix it right.

Warning Signs Your Ductwork Needs Professional Repair

Uneven Temperatures Between Rooms

You walk from the living room to the back bedroom and the temperature drops twenty degrees, even though the thermostat says 72 and the furnace has been running for an hour. You've checked the vents — they're open — but the airflow is weak or non-existent in certain rooms while others get blasted with too much air. This is almost always a duct leak, a disconnected boot, or a crushed flex run somewhere between the furnace and that problem room. Conditioned air is escaping into your attic, crawlspace, or wall cavity instead of reaching the living space, and you're paying to heat or cool spaces you don't live in.

Whistling, Rattling, or Banging Noises From the Ducts

Every time the system kicks on, you hear a high-pitched whistle from somewhere in the ceiling, or a metallic bang that echoes through the walls. Sometimes it's a vibration or rattle that gets louder as the blower ramps up, and you can't pinpoint where it's coming from. Whistling usually means a gap or hole in the duct seam where air is escaping under pressure. Banging is often a loose section of ductwork expanding and contracting with temperature changes, or a piece of metal that's come unstrapped and is moving when air rushes past it. That noise is a leak or a failure point, and if you ignore it long enough, the seam will split or the joint will separate completely.

Visible Dust or Debris Blowing From Registers

Every time the blower runs, you see a puff of dust come out of the vents, and you're dusting furniture more often than you used to. Sometimes you'll see insulation fibers, cobwebs, or even bits of construction debris coming through the registers. Your return duct has a leak or a gap, and it's pulling in air from an attic, crawlspace, or wall cavity full of dust, insulation, and whatever else has settled there over the years. The filter only catches what comes through the return grille — it can't stop contaminants entering through a hole upstream. You're breathing whatever's in your attic or crawlspace, and that's a health issue on top of an efficiency problem.

Skyrocketing Energy Bills With No Change in Usage

Your electric or gas bill has jumped 40 percent compared to the same month last year, but you haven't changed how you use the house — same thermostat settings, same occupancy, same habits. The system runs constantly, and it feels like it's never satisfied. You're conditioning space you don't live in. Duct leaks in an attic or crawlspace mean you're pumping heated or cooled air into an unconditioned zone, and the system has to run twice as long to bring the living space up to temperature. A single large leak can waste 20 to 40 percent of your system's output, and every month you wait is another month of paying for energy you're not using.

Rooms That Smell Musty or Like the Crawlspace

There's a damp, earthy smell in certain rooms that doesn't go away no matter how much you clean or air things out. It smells like the crawlspace or the attic — that unmistakable musty, stale odor that's stronger when the system first kicks on, then fades as the air circulates. You have a return leak pulling air from a damp crawlspace, basement, or attic, and that air carries moisture, mold spores, and the smell of whatever's down there. In Southern Illinois, where crawlspaces can stay damp for months, this is a common problem in homes with original or poorly sealed return ducts. Moisture in your ductwork leads to mold growth inside the ducts themselves, and you're spreading spores every time the blower runs.

Weak Airflow From Some or All Registers

You hold your hand up to a register and feel barely a trickle of air, even though you can hear the blower running full-blast. Some vents have strong airflow, others have almost none, and you've checked — the dampers are open, the filter is clean, but the air just isn't moving like it should. Somewhere between the plenum and that register, the duct is crushed, kinked, disconnected, or blocked. Flex duct in an attic or crawlspace can get compressed by insulation, stepped on during other work, or pulled loose from its collar. Sometimes we find ductwork that was never connected in the first place — a boot that's supposed to attach to a register box but is just hanging in the wall cavity, blowing air into the stud bay.

Common Causes of Ductwork Failure

Disconnected or Loose Duct Joints

Ductwork is assembled in sections — trunk lines, branches, boots, and plenums all connect with collars, drives, and fasteners. Over time, vibration from the blower, temperature cycling, and house settling can loosen those connections. Flex duct can pull off its collar if it wasn't strapped properly during installation, and rigid duct joints can separate if the drive cleats rust out or if someone bumped the ductwork during other work in the attic or crawlspace. In older homes across Southern Illinois, we see original ductwork that was never sealed with mastic in the first place — just sheet metal screws and hope. We find the disconnected section, clean the mating surfaces, and reattach it with the proper fasteners and mastic sealant, then add new hangers and supports to keep it in place long-term.

Crushed or Kinked Flex Duct

Flex duct is lightweight and easy to install, but it's also easy to damage. We see it compressed under blown insulation in attics, stepped on by other trades, or kinked where it makes a tight turn. Sometimes it was installed with too much length and left to sag, creating low spots where condensation pools and the airflow chokes down. In Southern Illinois attics, where summer heat can hit 140 degrees and insulation gets piled on thick, flex duct that wasn't properly supported will collapse under the weight. We pull back the insulation, inspect the full run, and replace any crushed or kinked sections with new flex duct installed at the correct length and with proper support every four to six feet.

Leaking Seams and Unsealed Joints

Ductwork is full of seams — every joint, every transition, every takeoff is a potential leak point. Older ductwork was often assembled with nothing but sheet metal screws and duct tape, which degrades and falls off within a few years. Even newer systems can have leaks if the installer didn't apply mastic sealant to every joint, and temperature cycling causes the metal to expand and contract, which opens up gaps over time. In homes with original ductwork from the '70s, '80s, or '90s, we routinely find seams that are 30 to 50 percent open. We seal every seam and joint with mastic and fiber mesh tape — the only method that lasts. We don't use foil tape or duct tape; they fail.

Poorly Designed or Undersized Ductwork

Not all ductwork is created equal. Sometimes the original system was undersized for the house — not enough return air, trunk lines that are too small, or branch ducts that can't deliver the required CFM to each room. Other times, the layout is inefficient: long runs with too many bends, undersized boots, or a return grille that's too small for the blower capacity. We see this often in older Southern Illinois homes where the ductwork was designed for a smaller furnace and never upgraded when the equipment was replaced. This isn't a simple patch job — it requires a redesign. We perform a load calculation and airflow analysis to determine what each room needs, then we modify or replace sections of ductwork to meet those requirements.

Damage From Rodents, Pests, or Moisture

Crawlspaces and attics are prime real estate for mice, rats, squirrels, and insects. Rodents chew through flex duct insulation and inner liners to make nests, and we've pulled out ductwork packed with acorns, insulation, and droppings. Moisture is another enemy — if a crawlspace floods or a roof leak drips onto ductwork, the insulation gets soaked, the sheet metal rusts, and mold starts growing. In Southern Illinois, where humidity runs high and crawlspaces can stay damp for months, moisture damage is a recurring issue in homes without proper vapor barriers or drainage. We remove and replace any ductwork that's been chewed, nested in, or contaminated with droppings, and we address the underlying moisture problem before we close everything back up.

What to Expect During the Service Visit

When you call Smith Heating, Air & Sheet Metal for duct repair, we don't start by tearing into walls or cutting access holes. We start by listening — to you, and to your system. You'll walk us through what you've noticed: the cold room, the noise, the dust, the bill. We'll ask when it started, whether it's gotten worse, and what you've already tried, because that conversation tells us where to look first.

Next, we'll do a visual inspection of every accessible section of ductwork — attic, crawlspace, basement, wherever your ducts run. We're looking for obvious disconnects, crushed sections, rust, gaps, and signs of pest activity. We'll check the airflow at every register with a flow hood or anemometer to see which rooms are getting what they should and which aren't. If we suspect hidden leaks, we'll use a duct pressure test — we seal off the system, pressurize it, and measure how much air is escaping.

Once we've found the problem, we'll explain what we found, why it's happening, and what it'll take to fix it. If it's a simple disconnect or a single crushed run, we can often handle it the same day. If it's a bigger job — multiple leaks, a redesign, or extensive replacement — we'll give you a detailed estimate and a timeline. We don't patch over problems; we fix them right, with mastic on every seam, proper hangers and supports, and code-compliant materials that will last.

Duct Repair & Service Coverage Across Southern Illinois

We bring the same diagnostic tools, sheet metal expertise, and commitment to quality to every duct repair call across the region.

Southeastern Missouri: Duct Repair & Service — Perryville, MO

Related Services

Duct repair often goes hand-in-hand with other sheet metal work. If we're already in your attic or crawlspace fixing leaks, it's a good time to evaluate whether your ductwork layout is serving you well — or whether a custom fabrication or full ductwork installation makes more sense than patching an old system that's reached the end of its useful life. We'll give you an honest assessment of whether repair or replacement is the smarter long-term investment.

Ready to Stop Wasting Energy and Start Breathing Easier?

You shouldn't have to live in a house where half the rooms are comfortable and the other half aren't. You shouldn't be paying to heat or cool your attic while your bedroom stays cold. Duct problems don't fix themselves — they get worse, cost more, and make your equipment work harder until something else breaks.

Smith Heating, Air & Sheet Metal has been solving ductwork problems across Southern Illinois for decades. We know what a good duct system feels like, sounds like, and costs to run — and we know how to get yours back to that standard. If you're ready to stop guessing and start getting the comfort you're paying for, reach out to us today and let's schedule a time to take a look.