Duct Repair and Replacement in Charleston, SC

Duct repair and replacement in Charleston starts with finding out where your air is going. ENERGY STAR estimates that about 20 to 30 percent of the air moving through a typical home's ducts is lost to leaks, holes and poor connections.

Aero Air Techs traces those losses, seals or rebuilds the failed sections and checks the airflow afterward, with a clear, upfront quote before work begins.

Leaks do double damage here. A supply leak dumps cooled air into an attic or crawl space. A return leak draws air from those same spaces into the system, and in a Lowcountry summer that air is hot and humid. Your AC then has to cool and dry it all over again.

How do leaky ducts show up in a Lowcountry home?

Your house usually tells you before anyone opens a panel. Match what you notice to the likely cause.

What you notice	Likely duct problem	Where to look first
A room that never cools	Crushed, kinked or disconnected flex	The run feeding that room
Summer bills climbing with no new usage	Leaks at joints and collars	Attic or crawl space trunk
Sticky air with the AC running	Return leak pulling in humid air	Return drop and filter cabinet
Extra dust near the returns	Return leak in a dusty space	Boots and return connections
Whistling at the registers	Undersized ducts or closed dampers	Trunk sizing and damper positions
Water on or under a duct	Torn jacket and sweating	Insulation on the cold section

Our post on the signs of leaking ductwork walks through a simple check you can do at home.

Why duct repair and replacement in Charleston often starts under the house

Location decides how ducts fail here. ENERGY STAR lists ducts in attics, crawl spaces and garages as a warning sign in themselves, and that describes a lot of homes around Charleston.

Crawl spaces and raised homes

Raised homes and brick ranches often run ducts under the floor, where moisture sits around them for months. Rodents tear the jackets, straps let go and flex sags onto the ground. Where a house sits on open piers, the ducts also take on weather from the yard.

Attics in slab homes

Many subdivision homes on slabs put the whole system overhead. Summer attic heat works on tape and flex jackets, and people walking through an attic for storage or repairs can crush a run without knowing it.

Older homes with added ducts

Homes that gained central air after they were built tend to have whatever route fit at the time. Long runs, sharp bends and undersized returns are common. Sealing helps, but it cannot make a small duct carry more air.

Seal, repair or replace?

Pick the smallest job that solves the problem. Here is how we think about it.

Duct sealing. This suits sound ducts with leaky joints. Mastic or metal tape goes on the seams, and ENERGY STAR warns that ordinary duct tape does not last.

Section repair. This suits a torn jacket, a crushed run or a collar that pulled loose. We replace that run and leave the rest alone.

Full replacement. This fits ducts that are wet, rodent-damaged throughout, badly undersized or near the end of their life. New ductwork also gives you the chance to shorten runs and fix the layout.

Resizing. If the rooms are starving for air, the duct design itself may be the fault. Manual D is the trade's method for sizing ducts from the airflow each room needs, and it is worth asking for before any full replacement. Pairing new ducts with AC replacement can make sense too, since a new system depends on the ducts it feeds.

Wet or moldy insulated duct is its own case. EPA says it cannot be effectively cleaned and should be removed and replaced. We do not offer mold remediation, so we replace the duct and point you to a specialist for anything beyond it.

What the job includes

Every duct job gets the same core items, scaled to its size.

• A walk of the trunks, branches, boots and returns you have, in the attic or crawl space
• Leak finding at the seams, collars and the filter cabinet
• Mastic or metal tape on joints, with no ordinary duct tape
• New runs, collars or boots where the old ones failed
• Insulation on ducts in unconditioned spaces, which DOE says is usually very cost effective alongside sealing
• Straps and supports so flex stays off the ground and away from sharp bends
• An airflow check at the registers when the work is done

DOE adds one point worth asking any contractor about. All duct sealing should be tested by a qualified professional for combustion safety and airflow, which matters most in a home with gas appliances, since tighter ducts can change the pressures around them.

From first crawl to final airflow check

1. Describe the problem. Tell us which rooms suffer and when it started.
2. Inspect the ducts. We get into the attic or crawl space and take photos you can see.
3. Lay out the options. You hear what to seal, repair or replace, and what can wait.
4. Quote. You see the scope and the price before anything starts.
5. Do the work. We protect the house, repair or rebuild and close up what we opened.
6. Check the airflow. We run the system and read the registers we worked on.

Flood rules, permits and a reported rebate

Three outside rules can shape a duct job here.

Flood zones. City of Charleston flood guidance says machinery and equipment in the Special Flood Hazard Area must be raised to the Design Flood Elevation, and it names HVAC units and ductwork. Moving a run may matter on a raised home in those zones. Other towns set their own rules, so check with yours.

Permits and licensing. Each town and county runs its own permits, so ask yours what applies to duct work. SC LLR oversees contractors, and you can check any contractor's license on the LLR lookup.

Rebates. Dominion Energy South Carolina's rebate list includes ductwork improvements in existing homes, reported at up to $300 by EnergyWise Shop and aggregators in 2026, a figure not read from Dominion's own page. The program is reported to require a licensed contractor, an invoice and an application within 90 days, and DIY work does not qualify. Confirm every detail on Dominion's rebate page before you count on it, including whether your contractor qualifies, and read our SC rebate guide for the wider picture.

What drives duct replacement cost?

Four things set the price.

• Scope. One torn run and a whole new system are very different jobs.
• Access. A tight crawl space or low attic slows everything down.
• Materials. Sheet metal trunks, flex and duct board each cost and install differently.
• Design changes. Adding a return or resizing a trunk adds labor and material.

We quote it line by line so you can see what each part costs. Ask whether any new materials carry a manufacturer's warranty, and read those terms. If a dirty system is the worry, read about air duct cleaning first, because EPA says it is only worth considering in specific cases. If moisture is still the problem after the repair, a whole home dehumidifier may be the next step.

Why call Aero Air Techs about your ducts?

You see what we saw, and you choose the scope.

• 4.9 on Google, the score across our 16 reviews in October 2026.
• Plain explanations. One customer wrote that the crew "clearly explained the necessary work."
• Careful work. Another said the visit "Paid attention to detail."
• A quote before work begins, so the scope and the number are on the table first.

We are based in Charleston and serve the surrounding areas, including North Charleston, James Island, Folly Beach and Summerville. Tell us where the ducts run and we will plan the visit from there.

Where the ducts run depends a lot on where the house sits.

• North Charleston: older frame cottages often hide runs in tight crawlspaces.
• James Island: post-war crawlspaces and tide-wet ground are hard on insulation.
• Folly Beach: ducts under a raised floor take the weather, and nothing may hang from breakaway walls.
• Summerville: old houses near the historic core may need duct routes planned around the structure.
• Mount Pleasant: an upstairs system with attic ducts takes the most roof heat.
• Johns Island: long, narrow attic runs in newer homes can hide crushed flex.
• Moncks Corner: older in-town ducts are often the first thing to check after a new system disappoints.
• Sullivan's Island: straps and hangers under raised cottages rust along with the unit.