My A/C company said to call a remediation company before they touch the ducts. Why?

The A/C company came out to look at the system. The tech opened the air handler, looked at the ducts, and then closed it all back up. “I’m not touching this,” he said. “You need a mold remediation company first.”

Now you’re standing in the hallway wondering what that means. Is the house unsafe? Why won’t they just clean it? And who are you supposed to call?

That exact call came to us this fall from a homeowner on the West Bank. There was a musty smell coming through the A/C and a dark spot on the guest bedroom ceiling. His HVAC company had looked and told him to get a remediation company in before anyone worked on the ductwork. Here’s why that was the right call, and what happens next.

Why a good A/C tech stops

When there’s mold growing in an air handler, on the coil, inside the ducts or in the chase around them, working on the system can spread it. Cutting into a duct, pulling a coil or running a duct-cleaning machine through a moldy system can push spores and debris through every supply vent in the house. That turns a problem in one closet or attic into a problem in every room.

Louisiana licenses mold remediation as its own trade, separate from A/C work. A good A/C tech knows where their work stops. Stopping and sending you to a remediation company protects you, and it protects them.

So the tech didn’t brush you off. They did you a favor.

What usually causes it

On the West Bank job, part of what we found was a drain problem at the unit. Water that should have run out the condensate line was staying where it didn’t belong and keeping things wet. Mold needs water, and an A/C system makes a lot of it. When the drain, the trap or the pan isn’t doing its job, the area around the air handler stays damp.

Other common causes: – A clogged drain line or a missing trap – A rusted or cracked drain pan – Ducts sweating in a hot attic – A leaky return pulling in damp air from the attic or a wall cavity – An old leak that was never dried out properly

What happens next: the order matters

The order is what makes this work.

1. Contain it. Before anything is opened, we seal off the work area with plastic and set up negative air, so air flows into the work area and out through a HEPA filter instead of out into your house. The A/C stays off while we work.

2. Remove and clean. Materials that can’t be cleaned, like moldy insulation, duct board or soaked drywall, come out and get bagged inside the containment. What can be cleaned gets HEPA-vacuumed and cleaned. On the West Bank job that included decontaminating the chase around the system.

3. Fix the water. This is the part that keeps it from coming back. We fix the drain, the trap, the pan or the duct problem that caused it. On that job that meant a condensate trap repair.

4. Confirm it. When a mold assessment is required, we order independent, disinterested third-party testing before and after. The person who says the work is done shouldn’t be the person who did it.

5. Then the A/C work. Once the area is clean and confirmed, the system can be cleaned, repaired or replaced without spreading anything.

Why one crew for both is simpler

Usually this is where it gets frustrating. The A/C company won’t touch it until the mold is handled. The mold company handles the mold but doesn’t fix the drain that caused it. Then you’re scheduling two companies, explaining the problem twice, and hoping they agree on who does what.

We hold the license for mold remediation and we do A/C work, so we handle both in order with one crew and one plan. That’s why the West Bank homeowner called us.

What’s at stake if it’s done in the wrong order

If someone cleans or replaces equipment before the mold is contained and the water source is fixed, you can end up paying for a new system that gets contaminated again, or with spores spread through ducts that were fine before. Doing it in order costs less than doing it twice.

What life looks like after

The musty smell is gone. The ceiling spot is fixed and painted. The drain runs where it should. And you have photos, a plain summary of what was found and done, and the third-party results when they were required.

Call and tell us what the tech said

Call (504) 702-1480. We answer day or night. Tell us what your A/C company found, and send their photos if you have them.

Learn about mold remediation and assessment, or see the towns we cover.

More from Field Notes: – That musty smell when the A/C kicks on, and what it usually means – Sweating ducts: what the water in your attic is telling you

Questions about mold and your A/C

Why won’t my A/C company clean the moldy ducts? Disturbing mold without containment can spread it through the house, and Louisiana licenses mold remediation as its own trade. A good tech stops and refers you.

Is it safe to run the A/C if there’s mold in the system? It’s best to keep it off where you can until the area is contained and looked at, so it isn’t blowing through the house. Call us and we’ll tell you what makes sense for your situation.

Do I need two companies, one for the mold and one for the A/C? Not with us. We do the mold remediation and the A/C work, in the right order, with one crew.

Who decides when the mold is gone? When a mold assessment is required, an independent, disinterested third party. We order that testing so the clearance call isn’t ours to make.