Mold in Air Ducts: Duct Mold Removal & Replacement in Austin

Ducts carry cold air through hot, humid spaces. In most Central Texas homes, that means an attic that can top 120 degrees in summer. Where the duct surface drops below the dew point of the air around it, water condenses. Add dust and you have mold food and moisture in the same place.

The usual culprits are:

• Thin, torn or missing duct insulation that lets the outside of the duct sweat
• Leaky connections that pull humid attic air into the return side
• Mold growth in the air handler that spreads into the supply plenum and ducts
• Undersized or crushed ducts that slow airflow and let moisture linger
• Supply registers in bathrooms or near exterior doors that collect condensation
• Water from a roof leak or a drain overflow that soaked duct insulation

Duct work is part of the HVAC scope on a mold project, so it’s coordinated with the remediation contractor, the air handler work and the moisture fix:

1. An independent, licensed mold assessor evaluates the home and writes the protocol. We coordinate with independent assessors and never assess our own projects.
2. The licensed mold remediation contractor leads the remediation and sets up containment. We work within it, isolating and protecting the HVAC system.
3. We HEPA vacuum and clean sheet metal plenums and boots where a home has them, and clean or replace registers and grilles.
4. We remove and replace contaminated flex duct, duct board and insulation, sized and sealed correctly.
5. We fix the HVAC-side cause: insulation, sealing, airflow, drain problems and humidity.
6. An independent assessor performs clearance, and on regulated projects the remediation contractor issues the Certificate of Mold Damage Remediation. We document our HVAC work for the project records.

Many older Austin homes have ductwork that’s poorly sealed and was never sized for the house. If ducts are contaminated and also leaky, crushed or undersized, replacing them solves more than one problem. New, properly sized and sealed ducts with the right insulation are much less likely to sweat, and they help the system control humidity.

Our ductwork team designs and installs duct systems, so replacement is done to proper sizing, not just swapped piece for piece.

Routine duct cleaning removes dust and debris. It’s useful after a renovation or when there’s heavy buildup. Mold in ducts is a different job: it needs a protocol, containment where required, removal of materials that can’t be cleaned and a fix for the moisture problem. If you’re seeing mold, not just dust, the ducts should be handled as part of a mold project with a protocol, not a standard duct cleaning.

Want a whole-home treatment of the air and surfaces after the physical work is done? Our sister company offers Pure Maintenance dry fog treatment.

Duct mold is usually connected to other parts of the system:

• HVAC restoration, the HVAC side of mold remediation: AC units, coils and ducts
• Mold in your AC unit: coil and air handler restoration
• Dry fog mold treatment: an optional whole-home step through Pure Maintenance of Central Texas

Want to understand your options before you call? Our homeowner guides on ducts and mold are written by our team for Central Texas homes.

• Best Practices for Mold Prevention in Your HVAC System
• The Importance of Properly Sized Ductwork for Your HVAC System
• Warning Signs of Mold in Your HVAC System
• Dry Fog Mold Treatment vs. Traditional Mold Remediation

Browse all homeowner guides in the Gold Eagle Resource Center