How to Pass HVAC Clearance Testing After Mold Remediation
- Brandy Thome
- Jun 4
- 2 min read
What Inspectors Are Really Looking For- and Why Most Inspections Fail the First Time
When mold contamination strikes a home or commercial building, thorough remediation is essential; but if the HVAC system isn’t properly addressed, all that effort can go to waste.
Clearance testing is the final step in any mold remediation project. It's how professionals verify the space is safe for re-occupancy. But here’s the truth: HVAC systems are one of the most common reasons mold remediation projects fail clearance.
So how do you ensure your system passes?
Understand What Clearance Testing Is — And Isn’t
Clearance testing involves:

Visual inspections for signs of dust, debris, and microbial growth
Air sampling to measure spore counts or particulates
Surface sampling of HVAC components or adjacent areas
Review of HVAC system condition and accessibility
But clearance testing isn’t just about numbers on a lab report. It’s about evidence of thoroughness -and the HVAC system is one of the most overlooked zones.
Why HVAC Systems Fail Clearance Testing: Even after expensive remediation
The evaporator coil may still have biofilm (a sticky mix of mold, bacteria, and dust)
The blower wheel may show signs of neglect or cross-contamination
Internally lined ducts or fiberglass insulation can retain spores
Lack of accessibility to the internal components of the air handler and ductwork.
Remember: If a ventilation inspector or hygienist can’t access the system or confirm it’s clean, they can’t pass it.
🔍 What Inspectors Are Looking For
To pass clearance, your HVAC system must:
Be clean to the eye and touch (no visible dust or mold)
Have documented remediation (with before-and-after photos)
Allow access to key components (coil, plenum, blower, ducts)
Show evidence of proper sealing, disinfection, and NADCA-standard cleaning
A NADCA Certified Ventilation Inspection is often part of the clearance review process, especially when the HVAC system was part of the original mold contamination.
Tips to Ensure Your System Passes
Use a licensed and certified HVAC mold remediation team, not just a duct cleaning company
Always consider replacing contaminated insulation inside the system
Encapsulate contaminated insulation if it can’t be removed
Photograph every cleaned section, including inside the coil housing and plenum
Seal all access panels and label new ones added during cleaning
Don’t wait for clearance testing to “see how it went”- prepare for it intentionally
Our Process at EnviroAir Systems
At EnviroAir Systems, we take clearance testing seriously — because your health depends on it. Our approach includes:
NADCA-standard source removal of all contamination
Detailed before-and-after documentation
Post-remediation assessment walkthroughs
Coordinated clearance testing with third-party hygienists
We don’t consider a job complete until the system and the space is verifiably clean.

📞 Schedule a Pre-Clearance Inspection Today
Don’t leave HVAC clearance testing to chance. If your project is nearing completion or remediation has already occurred, let us inspect your system before testing.
Call 813-644-9261 to book an EnviroAir Systems Certified Ventilation Inspection.
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