Lennox Ductwork Repair Nationwide

Lennox Ductwork Repair: The Marietta Owner’s Guide

We repair and replace Lennox-compatible ductwork throughout Marietta, and most duct repair jobs run between $250 and $900 installed, depending on how much of the run is damaged and how accessible it is. If you’ve got a collapsed flex duct, a disconnected boot, or a crushed trunk line, we typically get it repaired same-day or next-day. The way most Marietta homeowners discover the problem is uneven cooling: one bedroom stays hot all afternoon while the hallway feels like a meat locker.

Call (762) 240-5599

In crawl spaces and attics across East Cobb, Sandy Plains, and around Kennesaw Mountain, we see the same story play out: a run of duct gets pinched, torn, or simply separates at a seam, and the conditioned air leaks into a space nobody lives in. You pay to cool the attic, the system runs longer, and the room you actually wanted cool never quite gets there.

Which Lennox Models This Applies To

Ductwork is far less model-specific than a control board or inducer motor. The flex duct, sheet metal trunk lines, boots, and registers in a Lennox system are sized to the airflow of the equipment, not to a particular series number. That said, the issue you run into with Lennox is less about the unit’s model and more about the duct sizing and static pressure the system is designed for. Lennox variable-speed air handlers, like the CBX and CBA series, and the Signature and Elite series condensers, are built to move specific cubic feet per minute. When a section of duct collapses or separates, the blower still pushes the same air, but it finds the path of least resistance: a hole in the attic. The first thing we check on any Lennox duct repair is whether the remaining duct is sized appropriately for the blower’s CFM rating. If a previous homeowner or a handyman patched a section with smaller-diameter flex, you’ll end up chasing the same noise and pressure problems forever.

When it comes to replacement materials, the honest answer for ductwork is that OEM-labeled “Lennox” duct is not a meaningful category. Lennox builds the equipment; the flex duct, collars, and registers come from duct manufacturers. What matters is quality: we use insulated flex rated for attic conditions, metal collars, proper mastic sealing, and UL-listed materials. No brand markup for a name printed on a box of flex.

Signs Your Lennox Ductwork Is Failing

• One room never reaches the temperature on the thermostat. A disconnected or crushed branch line means that room simply isn’t receiving its share of the airflow. Closing doors doesn’t help; the air isn’t reaching the register at all.
• Dust blooms around one register while the rest of the house looks normal. When a return duct pulls air from the attic instead of the room, it draws in loose insulation fibers and dust. You’ll see gray fuzz accumulating on that vent.
• The system runs longer, and the energy bill rises in fall and spring. Air leaking into an unconditioned attic or crawl space means the blower runs and runs to hit a set point that the leak keeps moving. Simple math: lost air is lost money.
• You hear flapping or a rhythmic thump when the blower starts. That’s often a section of flex duct that’s worked loose from its collar and is whipping in the airstream each time it cycles. Left alone, it tears fully and fails outright.
• There’s visible condensation or soft spots on the duct in the crawl space. Warm, humid Marietta air meeting a cold duct that’s lost its insulation wrap creates water. Over time, that water soaks the insulation, drips onto joists, and tells you the barrier is gone.

Replacement Cost & What’s Included

For Marietta homes, expect these installed ranges:

• Reseal or reattach a single flex run at the boot or collar: $150 – $300
• Replace a short section (5 – 15 feet) of damaged flex duct: $250 – $550
• Replace a long run or multiple branch lines with new insulated flex and proper support: $550 – $900
• Repair or replace a sheet-metal trunk or plenum section: $400 – $850, depending on gauge and accessibility

What moves the number is access. A duct in a walkable attic with decking costs less to reach than one under a low-slung East Cobb crawl space where we’re working on our backs. Every written quote we hand you includes the parts, the mastic and sealing compound, the labor, and the exact size of the new duct. And because Victor Mancini runs this company on The Kingswell Way, the price is written before any work starts. If it’s a $275 re-seal, that’s exactly what’s on the paper; it doesn’t become $410 by the time the tool bag opens.

DIY or Call Us?

Two honest things are true at once. First, a homeowner can safely inspect a lot: look for collapsed flex in an accessible attic, feel for air leaking at a boot connection, and check that registers are open and unobstructed. Second, duct repair done wrong is not just wasted effort. Resealing with duct tape (the store-bought gray stuff) fails inside two or three Marietta summers. A loose connection reattached without proper mastic and a real zip-tie or metal clamp will separate again. And crawling under a house to patch a run you can barely see means breathing insulation dust and risking a badly done job that will just cost more to redo properly. The repair itself is not high-voltage or high-tension, but it is dirty, cramped, and unforgiving when the seal fails. If the job is anything beyond tightening a visible register, call (762) 240-5599 and let us look at it. The estimate is free, and the repair carries our 365-day guarantee.

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