Evaporator coil and drain pan
The wettest part of the system. A pan that holds standing water or a slimy coil is the most common starting point.
HVAC mold removal
HVAC and Air Duct Mold Removal in Los Angeles
Mold in the air handler, on the coil, in the drain pan or through the ductwork cleaned or replaced, with the condensation problem behind it tracked down.
Phone answered 24 hours a day. Talk to a remediation specialist now.
- Moisture source found and fixed
- Containment + HEPA filtration
- Homes and commercial
Why HVAC systems grow mold
An air conditioner pulls moisture out of the air. That water condenses on the cold evaporator coil, drips into a drain pan and leaves through a condensate line. When any part of that path fails, the inside of the system stays wet and dark, which is exactly what mold needs.
From there, the blower carries spores through the ductwork. Dust in the ducts gives them something to grow on, and uninsulated or poorly sealed ducts in a hot attic can sweat on the outside too.
Our article on mold in air ducts covers the warning signs. This page explains how the removal is done.
Where in the system we find it
Air handler cabinet and blower
Internal insulation lining the cabinet absorbs moisture and dust and can grow mold that can't be scrubbed out.
Supply and return ducts
Growth often clusters near the air handler and at registers in humid rooms. Return ducts pull air from the house, so they carry its dust and moisture too.
Registers and grilles
Dark spotting around a supply register is often condensation on a cold grille, but it can also point to growth further up the duct.
Signs your HVAC has a mold problem
- A musty or dirty-sock smell when the air conditioning starts
- Dark spotting on or around supply registers and return grilles
- Water around the air handler, or a drain pan that's always full
- Water stains on the ceiling under attic ducts or the air handler
- Visible growth on the coil or inside the cabinet when the access panel is off
- People in the home noticing allergy-type symptoms mainly when the system runs. The EPA and CDC note that mold can trigger these symptoms in some people; if you have health concerns, speak with a doctor.
Seeing or smelling mold? Call and describe what you're dealing with. We'll tell you what it likely means and arrange an inspection. Phone answered 24/7.
How we remove mold from an HVAC system
The system is shut down for the work, and the rest of the house is protected while components are open.
Inspect the whole air path
Air handler, coil, pan, condensate line, plenums, a sample of duct runs and the registers, plus any mold in the rooms the system serves.
Seal off and set up negative air
Registers and returns are covered, and the work area is kept under negative pressure so opening the system doesn't release spores into the house.
Clean the air handler
Coil, pan, blower and cabinet surfaces are cleaned. Mold-contaminated internal insulation is removed and replaced.
Deal with the ducts
Rigid duct is cleaned with HEPA-filtered equipment. Moldy flex duct and duct board are usually replaced rather than cleaned.
Fix the moisture cause
A clogged condensate line, a rusted pan, missing duct insulation or an oversized unit that never dries the air. We flag the repairs that need an HVAC technician.
Verify before restart
A final visual check, a new filter, and clearance sampling if you want documented results.
Clean or replace?
What the component is made of decides what can be saved.
| Component | Usually cleaned | Usually replaced |
|---|---|---|
| Sheet metal duct | Yes, unless internally lined and contaminated | Lined sections with growth in the liner |
| Flex duct | Rarely | Runs with growth inside or wet insulation |
| Duct board | Rarely | Sections with visible growth |
| Coil and drain pan | Yes | Pans that are cracked or rusted through |
| Cabinet insulation | No | Any lining with mold growth |
Los Angeles systems
What's different here
Many LA homes have the air handler and ducts in the attic, where summer heat makes cold, poorly insulated ducts sweat and a blocked condensate line can go unnoticed for a long time. That's why duct problems and attic mold so often turn up together.
Inland valley homes in Burbank and Glendale run their AC hard through long hot spells, which puts a lot of water through the drain. Closer to the coast, higher humidity from the marine layer keeps ducts and registers damp in rooms with poor airflow.
What affects the cost
- How far the growth has spread: coil and pan only, or through the ducts
- Duct type, since flex duct and duct board usually mean replacement
- Number of runs, registers and returns in the system
- Access to the air handler: attic, closet, garage or crawl space
- Mold in the rooms the system serves, which is handled separately
- HVAC repairs needed to stop the condensation
Related services and service areas
If the smell has no clear source, a mold inspection can separate a system problem from a leak in a wall. For offices, restaurants and apartment buildings with larger systems, see commercial mold remediation.
We work on HVAC mold across Los Angeles and nearby cities. See the full list on our service areas page, or call (424) 479-7915. The phone is answered 24 hours a day.
Questions homeowners ask
Can moldy flex duct be cleaned?
Rarely well. Flexible duct has a thin inner liner that can tear during cleaning, and growth in the insulation layer can't be reached. When flex duct has mold inside, replacing the affected runs is usually the better call. Rigid sheet metal duct can often be cleaned.
Should I keep running my AC if I think there is mold in it?
If you smell mustiness every time the system turns on, or see growth at the registers, it's better to limit use until someone has looked at it. Running the system can move spores from the air handler into every room it serves.
Will duct cleaning alone fix a moldy HVAC system?
Usually not. Duct growth is almost always fed by moisture at the coil, drain pan or condensate line, or by sweating ducts in a hot attic. If that isn't fixed, cleaned ducts grow mold again.
Do you need to test before HVAC mold removal?
Not when growth is visible on the coil, pan or registers. Sampling can help when the only sign is a smell and nothing can be seen. Our mold testing page covers when it is useful.
Talk to a specialist
Call about your mold problem
Tell us what you're seeing, smelling or worried about. We'll ask a few questions, explain what it likely means, and arrange an inspection and a written scope.
(424) 479-7915Phone answered 24 hours a day, 7 days a week
Call now, 24/7- We find and fix the moisture source, not just the stain
- Containment and HEPA filtration to keep spores out of clean rooms
- Homes and commercial properties across Los Angeles
Mold Remediation Los Angeles Experts
527 W 7th St #1495, Los Angeles, CA 90014
Open in Google Maps