Duct problems

Duct Repair vs. Duct Sealing vs. Duct Replacement

Homeowners usually search for "duct repair" because that is the natural phrase for "something is wrong with my ducts." In practice the trade splits the work into three distinct scopes, and matching the scope to the condition is the entire job of a good evaluation.

Getting this wrong is expensive in both directions: sealing a duct system that is physically failing wastes money, and replacing a system that mostly leaks at its connections spends far more than the condition warranted.

Here is how the three categories differ.

Reviewed by Duct Daddy

Written and reviewed by the Duct Daddy team, a duct leakage testing and duct sealing specialist serving Southeast Louisiana. This article is general guidance, not a diagnosis of your system.

The three scopes

Repair — mechanical failure

Disconnected runs, crushed or kinked flex, torn ducts, failed boot connections, damaged plenums and physically broken sections. These are corrected by hand: reconnecting, re-supporting, replacing a damaged section. Sealing a disconnected duct is not a repair, it is a cover-up.

Sealing — leakage through the assembly

Leakage at seams, joints, collars, takeoffs, boot connections and plenum penetrations. This is the diffuse, hard-to-find loss that adds up across a whole system, and it is what duct sealing is designed to address. It is also what a leakage test measures.

Replacement or modification — design and condition

Undersized branches, inadequate returns, badly deteriorated ductwork, systems extended piecemeal through renovations, and layouts that cannot deliver the required airflow. No amount of sealing corrects a design problem or restores a system that has reached the end of its service life.

Signals that point toward each scope

A register with almost no air at all often points toward repair — a disconnected or crushed run.
Broadly disappointing delivery across many rooms, with everything physically intact, often points toward sealing.
Rooms that have never been comfortable since the house was built or renovated often point toward design and sizing.
Visibly deteriorated, wet or collapsing ductwork points toward replacement.

These are indications, not diagnoses. Measurement and inspection settle it.

When to call a licensed HVAC service technician

Duct Daddy specialises in duct leakage testing and duct sealing. We do not perform mechanical HVAC repair, refrigerant work or equipment replacement. Contact a qualified HVAC contractor if any of the following apply:

Any scope decision should follow an evaluation of the actual system rather than a phone conversation.
Mechanical HVAC faults at the equipment require a licensed HVAC service technician.

How Duct Daddy approaches the decision

Duct Daddy specialises in duct leakage testing and duct sealing. That is deliberately a narrow specialty, and it means the evaluation has to be honest about the cases sealing does not solve.

We measure the system, inspect what can be reached, and tell you which of the three categories your system falls into. Where a system needs repair or modification rather than sealing, we say so — including when that means the right next call is your HVAC contractor rather than us.

The goal is not to sell sealing. The goal is to determine what the duct system actually needs.

More detail on the process: how air duct sealing works and how leakage is measured and verified.

Start with a measurement

An evaluation establishes the condition of the duct system before anyone proposes a scope of work.

Schedule a Duct Leakage Evaluation

Related guides

Browse every guide in the comfort guide.

Find out what your duct system is actually doing.

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