Last month I crawled under a Bluffton home and found a supply duct that had been blowing warm air into the dirt since sometime before Thanksgiving, and the homeowner had no idea why the back bedrooms stayed cold. Heating duct repair near me is the work of finding those failures, sealing or reconnecting the runs, and replacing sections too far gone to save. In most homes a crew can handle it in a single visit. If you’re searching for heating duct repair near me in the Lowcountry, the short answer is this: the ducts are usually the problem long before the furnace or heat pump is.
I’m Chase Howell, and at Howell-Chase Heating and Air Conditioning we have been opening up crawlspaces and attics around here since 1972. And after five decades of it, I can tell you the equipment gets all the attention while the ductwork does most of the suffering. The DOE’s research on residential duct systems puts this in hard numbers: leakage in a typical home can account for more than 30 percent of heating energy loss, meaning nearly a third of what your furnace produces never reaches a room.
A leaking duct system makes your heater run longer, pulls humid outside air into the house, and coats your furniture in dust. The house feels wrong, the bills creep up, and everybody blames the unit.
The ducts are the delivery system. A perfect heat pump connected to torn, sagging, disconnected ductwork is a good engine bolted to a broken driveshaft.
What Heating Duct Repair Actually Involves
“My rule of thumb after all these years: if I can feel warm air moving in a crawlspace in January, that homeowner is paying to heat the dirt. I’ve seen disconnected runs dump conditioned air into a crawlspace for entire seasons, a textbook example of what the DOE’s 30-percent-loss figure looks like in practice.”, Chase Howell, Howell-Chase Heating and Air Conditioning
A proper heating duct repair starts with an inspection, not a caulk gun. In most cases, we want eyes on every accessible run before anybody seals anything, because sealing a duct that should be replaced is wasted labor. We check the trunk lines, the takeoffs, the boots where ducts meet the floor or ceiling, and every joint and strap along the way.
The repair itself depends on what we find. Loose joints get pulled back together, screwed, and sealed with mastic (that thick gray paste that outlives everything else in the crawlspace).
Crushed or torn flex duct gets cut out and replaced, because you can’t un-crush flex. Boots that have separated from the subfloor get refastened and sealed at the perimeter. Missing or slid-down insulation gets rewrapped so the duct isn’t sweating or bleeding heat into unconditioned space.
So the job is part detective work, part sheet metal, part sealing. On an average home the whole thing runs a few hours to a full day, depending on access.
And access is the real variable. A duct I can reach in ten minutes is a cheap fix. The same failure behind a furnace platform in a crawlspace with fourteen inches of clearance is a different afternoon entirely.
Signs of Duct Leakage to Watch For
Uneven room temperatures are the number one giveaway. If one bedroom never warms up while the hallway roasts, the duct feeding that room is likely torn, disconnected, or pinched somewhere you can’t see. The system is making the heat. The heat is just not arriving.
Other signs I trust after all these years:
A heating bill that climbs even though your habits have not changed. Weak airflow at one or two registers while the rest blow fine.
Whistling or flapping noises when the blower kicks on. A dusty house no matter how often you clean (leaky return ducts vacuum dust out of the attic or crawlspace and deliver it to your living room). A musty smell when the heat runs, which usually means the return side is pulling air from under the house.
But the sign people miss most is the system that never seems to shut off. A furnace or heat pump sized correctly for the house should cycle. When a chunk of its output is dumping into the crawlspace, it runs and runs trying to satisfy a thermostat it can never quite reach. ASHRAE’s ventilation and duct performance standards flag exactly this symptom, a system that can’t reach setpoint is a system losing delivered capacity somewhere in the distribution path.
Homeowners tell me the unit is getting old and tired. Sometimes it is. Just as often the unit is fine and eleven feet of flex duct behind the water heater is lying on the ground.
What Lowcountry Humidity Does to Ducts
Coastal humidity is the reason duct systems around here fail faster than the same materials would inland, and coastal climate HVAC work has been one of our specialties for a long time. The EPA notes that moisture is among the primary contributors to indoor air quality problems, and a sweating, degrading duct system is one of the more reliable ways to introduce it.
Warm, wet air condenses on cool metal. Condensation rusts trunk lines, soaks insulation until it sags off the duct, and feeds the kind of biological growth nobody wants in their air stream. I have pulled duct wrap out of crawlspaces that weighed three times what it did going in, all of it water.
Actually, let me back up, because I go back and forth on part of this. For years we told people that more insulation on crawlspace ducts was always the answer, and I am not sure I was right.
Wrap a sweating duct without fixing the moisture and you have just hidden the problem under a blanket. Some of my own technicians push crawlspace moisture control harder than I historically have, and honestly, on the worst houses they have a point. I will admit the industry has moved on this question and I have moved slower than some.
What I will say flat out: any heating duct repair in this climate that ignores moisture is a repair you will be buying again. Seal the duct, yes. But look at why it was wet.
Crawlspaces, Attics, and Flex Duct Failures
Most duct failures in this area happen in three places: crawlspaces, attics, and anywhere flex duct was installed in a hurry. Crawlspace ducts take on moisture, rodent damage, and physical abuse from every plumber, cable installer, and pest technician who has crawled past them since the house was built.
I find ducts used as handholds. I find them used as shelves.
Flex duct has its own failure modes. The inner liner tears where the duct rubs a truss or a strap edge.
Long runs sag between supports, and every sag is a belly that kills airflow, because flex moves air well only when it’s pulled tight and run straight. Sharp bends near the boot choke a register down to a fraction of its rated flow. And the outer jacket degrades in hot attics until the insulation is exposed and shedding. ASHRAE duct design guidelines recommend support spacing of no more than four feet for flexible duct and prohibit sags that create more than a half-inch deviation per foot of run, standards that most field-installed flex duct simply doesn’t meet by the time we see it.
Metal duct fails differently. Joints work loose over decades of the blower pressurizing and relaxing the system, thousands of cycles a season.
Original fabric tape from the seventies and eighties dries out and lets go. Panned returns (where the builder used the floor joist cavity itself as a return duct) leak at every seam by design, and there isn’t much sealing can do for the worst of them short of running a real return.
The strap spacing matters more than people think. Flex wants support every few feet, with a wide strap that doesn’t pinch the liner.
Heating Duct Repair by the Numbers
Here is the picture of who you’re calling when you call us for ductwork:
| Figure | Detail |
|---|---|
| 1972 | Year Howell-Chase was founded, per our own records |
| 52+ years | Time we have spent working Lowcountry duct systems |
| Several SC communities | Beaufort, Bluffton, Brays Island, Fripp Island, Hardeeville, Hilton Head Island, Okatie, Parris Island, and Ridgeland, plus surrounding areas |
| Savannah, GA | The neighboring market we also serve |
| 24/7 | Emergency response availability, year round |
| 2 visits per year | Maintenance plan service schedule, with priority scheduling |
| 1 year | The Howell-Chase guarantee on our work |
I won’t put repair prices in a table, because I have never priced a duct job without seeing the ductwork first, and I am suspicious of anyone who will. Access, material, and how far the damage has spread set the number, and none of those show up over the phone. What I can promise is a real inspection before a quote, and members of our USA Club maintenance plan get their duct runs looked over on every scheduled visit.
Repair vs. Replacement Decision Criteria
Repair when the system’s bones are good and the damage is local. Replace when the design itself is the problem. That’s the whole decision, and here is how I sort it in the field:
| Situation | My call |
|---|---|
| A few torn or disconnected runs, sound trunk | Repair and seal |
| Rusted-through metal trunk sections | Replace the affected trunk, repair the rest |
| Flex duct with a shredded outer jacket throughout | Replace the flex, usually all of it |
| Undersized ducts that never heated the house right | Redesign and replace, sealing won’t fix a sizing error |
| Panned joist returns pulling crawlspace air | Add a real ducted return |
| Ductwork soaked by a flooded crawlspace | Replace what got wet, do not gamble on drying it |
The honest limits matter here. Heating duct repair is not the right fit for a system that was designed wrong on day one. We’ve seen this backfire: a homeowner pays to seal every joint on undersized ductwork, the house gets marginally better, and eighteen months later they pay again for the replacement they needed the first time. If a duct system can’t deliver the airflow the equipment requires, sealing it just makes a tight version of a bad design.
According to the DOE’s guide to residential duct systems, duct leakage in a typical home can account for more than 30 percent of heating energy loss, which is why proper sizing and sealing together matter more than either alone.
Why Duct Tape Fails on Ducts
Duct tape is the worst product ever named after the job it can’t do. The adhesive isn’t built for the heat cycling a supply duct goes through, so it dries, cracks, and peels, usually within a couple of seasons.
I have pulled off ribbons of it that were doing nothing but hiding the gap underneath. Cloth-backed hardware store tape belongs on moving boxes. If a previous repair on your ducts is silver and fuzzy at the edges, it has already failed.
Mastic, Foil Tape, and Sealing Right
The humidity problem from a few sections back shows up again here, because what you seal ducts with determines whether the seal survives a Lowcountry crawlspace. Mastic is my first choice for almost everything. You brush or glove it over the joint, it cures into a flexible gasket, and it doesn’t care about moisture, heat cycling, or time.
Done right, a mastic seal outlasts the duct around it. Energy Star notes that properly sealed ducts can cut heating and cooling costs by as much as 20 percent, and that number is conservative in a climate like ours.
Foil-backed tape rated for duct systems has a place too, mostly on clean, dry sheet metal and on flex duct collars where mastic gets messy. But surface prep decides everything with tape. Slap it over dusty metal and it lets go quietly over the next year, which is worse than never sealing at all, because everyone believes the job is done.
Then the insulation goes back on, and this step gets skipped constantly. A sealed but bare metal duct in a humid crawlspace becomes a condensation machine, and now you have traded a leak for a drip.
Seal first, insulate second, and make sure the vapor barrier on the wrap faces the right way and gets taped at the seams. Order of operations is half the trade.
Emergency Duct Failures: When to Call Immediately
A fully disconnected duct in the middle of a cold snap is an emergency, and we treat it like one. If your heat is running constantly and the house won’t hold temperature overnight, do not wait until the weekend is over. You’re paying full price to heat the outdoors, and in a hard freeze, an underheated house puts pipes at risk on top of everything else.
The other situation I take seriously is a return-side breach near combustion equipment. A leaking return close to a gas furnace can pull crawlspace air, and mold in air vents, whatever is in it, into your home’s air supply. That gets a same-day response from us, and it’s part of why we keep 24/7 emergency HVAC service staffed around the clock. Storms and severe weather are recurring hazards in this region, and a flooded crawlspace after one of them almost always means duct damage the homeowner can’t see from the hatch.
Squirrels in the attic ductwork, on the other hand, can usually wait for morning. Annoying, yes. Dangerous, rarely.
A Homeowner’s Duct Check Before Calling
You can gather most of what I need to know without tools. Walk the house with the heat running and note these:
Register-by-register airflow: hold your hand over each supply vent and rank them. Strong, weak, dead. The dead ones tell me where to crawl first. The thermostat gap: if the setpoint says one number and the house sits stubbornly below it, write down how far apart they stay. Sounds at startup: whistling, flapping, or a thump when the blower engages all point to specific failures. The crawlspace hatch: just tell me where it is and whether anything is stacked on it. Half my crew’s first hour on some jobs is moving a workbench, forty flowerpots, and a kayak to reach the access. Recent trades under the house: plumbers, pest control, cable installers. If anyone crawled under there in the past year, the odds of a kicked-loose duct go way up.
That list, plus the age of the house, gets me most of the way to a plan before I ever pull the truck up.
What Duct Work Costs Depends On
Access drives duct repair pricing more than materials do, and most homeowners assume the opposite. The parts on a typical duct job are cheap.
The labor of getting a human being and their tools to a joint behind the air handler in a tight crawlspace isn’t. Two identical leaks can be very different invoices depending on where they sit.
The other cost drivers are the extent of the damage, whether insulation and vapor barrier need replacing along with the duct, and whether moisture problems have to be addressed so the repair holds. I am deliberately not covering air duct cleaning in this guide, by the way.
Cleaning a leaking duct system is washing a car with the windows down, and I would rather you spend that money on sealing. The EPA’s guidance on duct cleaning makes the same point: address leaks and contamination sources first, then clean.
Heating Duct Repair Near Bluffton and Beyond
If your rooms heat unevenly or your system runs without resting, the ductwork is the first place I would look, and it’s the cheapest problem on the list to confirm. Howell-Chase Heating and Air Conditioning has been crawling under Lowcountry homes from our shop in Bluffton, SC for over five decades, and torn crawlspace duct is the single most common thing we find on winter heating repair calls. Call us and we will schedule a full duct inspection, register to trunk line, before anyone quotes you a dime.
By the Howell-Chase Heating and Air Conditioning Team
Frequently Asked Questions
How do I know if my heating ducts are leaking?
The clearest signs of leaking heating ducts are rooms that stay cold while the rest of the house heats normally, weak airflow at specific registers, and a heating system that runs almost continuously without satisfying the thermostat. Other reliable indicators include rising energy bills without a change in usage habits, a dusty house that stays dusty no matter how often you clean, and a musty smell when the heat runs. Any one of these points to duct leakage before it points to a failing furnace or heat pump.
Can leaking ducts actually raise my energy bills by a noticeable amount?
Yes, leaking ducts can waste up to 20 to 30 percent of the conditioned air a heating system produces, which translates directly into higher monthly bills. That lost output dumps into crawlspaces or attics rather than living spaces, forcing the system to run longer cycles to reach the thermostat setpoint. Homeowners often attribute rising bills to an aging unit, but the unit is frequently performing fine while the duct system bleeds its output into unconditioned space.
How long does a heating duct repair typically take to complete?
Most heating duct repairs on a single-family home are completed in one visit, ranging from a few hours to a full day. The primary variable is physical access. A disconnected joint in an open crawlspace takes far less time than the same failure located behind mechanical equipment or in a crawlspace with very limited clearance. Homes with multiple problem areas or extensive flex duct replacement may run toward the longer end of that range.
Why do heating ducts in coastal South Carolina fail faster than in other climates?
Warm, humid coastal air condenses on cooler duct surfaces, which corrodes metal trunk lines, saturates duct wrap insulation until it loses its grip and falls away, and creates conditions that promote biological growth inside the air stream. This moisture cycle is more aggressive in the Lowcountry than in drier inland climates, meaning the same flex duct or sheet metal installation that lasts decades elsewhere may show significant deterioration in a fraction of that time. Repairs that seal leaks without addressing the underlying moisture source tend to fail again for the same reason.