Duct Repair and Replacement in Hermann, MO

Signs of leaky ducts in an older home

Most duct problems show up as comfort complaints long before anyone looks in the crawl space. Match what you notice to the likely cause.

Why crawl-space ducts fail in the river valley

Damp, age and additions cause most of the failures we look for here. Humid summer air sits against cold metal under the floor, condensation forms on the duct, and over years it works on the insulation, hangers and joints.

• Older housing. Hermann's median home dates to 1956 (Point2Homes), and in ZIP 65041 the largest groups were built in the 1970s and 1980s. Tape from those decades has often let go.
• Additions. A branch tapped into an old trunk for a new room often starves the rooms past it.
• Water and animals. River-bottom crawl spaces can flood, and soaked insulation has to come out, because the EPA says cleaning will not save it. Rodents chew flexible duct too.

Return leaks matter most. A leaking supply loses air you paid to heat or cool, while a leaking return pulls crawl-space air into the house, which is why a damp smell can follow the blower.

How do we find duct leaks?

We start with the rooms that bother you and work back to the equipment. That means a walk of every reachable run, a check of the joints, boots and hangers, a look at the filter and return, and a comparison of airflow between rooms. Ducts inside finished walls and ceilings get judged by what happens at each register.

We also look at why the run failed. Sealing a joint without fixing the sag or the moisture that opened it buys only a short repair.

Seal, repair or replace: method options

Choose the smallest repair that will actually hold. Each method has a limit, and the condition of the metal decides.

ENERGY STAR says to insulate accessible ducts in crawl spaces, attics, unfinished basements and garages. For new ductwork, ask for a Manual D calculation so each run matches the airflow your equipment needs. In a brick house with no ducts at all, a ductless mini split may be the better answer.

What is included in duct repair work

Here is what you should receive, whether the job is one joint or a whole system.

• A clear list of each problem found and where it is.
• Repairs made with mastic, metal tape, new hangers or new sheet metal, not cloth tape.
• Insulation restored on any section we open in unconditioned space.
• A filter check and a final airflow check at the affected rooms.
• A combustion safety check where a gas furnace or water heater is involved.

Work proceeds step by step.

1. We go over which rooms and bills bother you.
2. We inspect the reachable runs and the return side.
3. We show you what we found, with photos when the space is tight.
4. We quote the repair before starting, with options where there are real choices.
5. We make the repairs and restore insulation.
6. We run the system and recheck the rooms and the equipment.

Small sealing and reconnection work often fits in one visit. A new layout takes longer and depends on access. Afterward, check your filter sooner than usual, because old dust can shake loose. A room may also need its register adjusted once the air balance changes.

What does duct replacement cost?

Access and length set the price. These are national guides, not our prices. PICKHVAC's 2026 figures put sealing a single run at $100 to $500, replacing a 10 to 30 foot section at $300 to $1,500, and whole-house repair or sealing at $800 to $6,000. It adds that tight access can raise labor by 25 to 100 percent.

This Old House lists replacement at $16 to $19 a linear foot in 2026, or about $4,700 to $5,600 for 300 feet. It notes asbestos abatement or mold remediation can add more than $2,000.

A crawl space you can barely enter costs more than an open basement. So do rusted hangers, insulation and any change in duct size. Request a clear, upfront quote for your layout.

Why Brian Grannemann Services for ductwork

• We are in the same river valley as your crawl space, working from Hermann since 1998.
• Stephanie H. wrote that Brian "completes the work correctly the first time," which is the standard for work that ends up hidden under a floor.
• Our trades cover heating, cooling, electrical and plumbing, so a nearby drain line or furnace connection stays with one company.
• A repair-or-replace call rests on trust, and Weber S. describes us as "fair and responsive to your needs."

How to keep repaired ducts tight

Keep water out of the crawl space, fix gutters and grading that send it there, and do not store boxes against the runs. Look at reachable joints once a year when you change a filter. A fall furnace tune-up is a good time to mention any new cold room.

We handle duct repair across the Hermann area, including Morrison, Berger, Owensville and Bland. Call (209) 563-1270 and tell us which room bothers you most.