Case Study: HVAC spread crawlspace mold throughout home

A Nashville homeowner called about mold in his HVAC system. He had already had his crawlspace remediated, but something was still wrong. The contamination had spread through the ductwork into the living spaces above. Multiple rooms were affected, and the mold test report confirmed it.

The homeowner had already remediated his crawlspace, but contamination persisted throughout the home. The HVAC system had been pulling contaminated air from the crawlspace and distributing it into the living spaces above. Testing revealed the scope of the problem.

The living room registered 41,320 total spores per cubic meter versus 7,050 outside, with Aspergillus/Penicillium and Cladosporium at ELEVATED counts. Hyphal fragments exceeded 100 per cubic meter, a direct indicator that active mold growth was nearby. The lab report was unambiguous: this space required remediation and should be vacated until complete.

The primary bedroom showed 27,400 total spores with the same elevated Aspergillus/Penicillium and Cladosporium counts and hyphal fragments over 100. The same recommendation applied: remediate and vacate. The crawlspace source had been addressed, but the HVAC system had already spread contamination into every room it served.

Claro performed a full duct cleaning and repair to address the HVAC system that had been distributing contamination throughout the home. Following duct work, Claro treated the entire home with its two-stage dry fog process: InstaPure Dry Fog to denature 99.99% of all mold in the air and on every surface without residue, followed by EverPure Dry Fog to provide a protective shield against microbial particles on all treated surfaces.

Post-treatment testing confirmed complete elimination: 13 CFU/m3 with only a single trace of non-sporulating fungi. The living room dropped from 41,320 spores to essentially clean. The primary bedroom dropped from 27,400 spores to clean. All elevated Aspergillus/Penicillium and Cladosporium gone. All hyphal fragments indicating nearby growth gone. The HVAC system was no longer spreading contamination through the home.

This case demonstrates why crawlspace remediation alone is not enough when the HVAC system has already distributed spores throughout the living space. The ductwork was actively recirculating contamination into every room. Duct cleaning and repair combined with whole-home dry fog treatment addressed both the distribution system and the airborne contamination it had created.