How to get HVAC company to properly clean mold chiller?« Back to Previous Page

We've lived in our Jumeirah villa for a couple of years, and every summer when the humidity spikes, I notice a faint but distinct mildew smell coming from the AC vents upstairs, especially in the bedrooms. I just had the main air handler cleaned, but the smell came back after a few days. I'm worried the problem is actually inside the mold chiller unit itself that I never see. What's the most effective way to get my HVAC company to properly clean and disinfect the mold chiller to prevent this from happening again?
Posted by Jose Davis
Asked on March 28, 2026 12:29 pm
Based on your description, this is a classic case of microbial contamination within the closed-loop chilled water system, not just the air handler. The "mold chiller" you're referring to is the fan coil unit (FCU) or potentially the entire chilled water circuit. The musty smell returning after a basic clean indicates the biofilm and spores are entrenched deep within the system, likely in the drip pan, coils, or insulation.

In the UAE's extreme humidity, standard cleaning by most HVAC companies is insufficient. They often just vacuum the drain pan and spray a superficial disinfectant that doesn't eradicate the root biofilm. You need to specifically request a comprehensive chemical cleaning and disinfection protocol.

Here’s what to demand from your HVAC contractor:

1. Full System Inspection: They must use a borescope to inspect the interior of the FCU, the drain pan, and the condensate drain line for microbial growth and sludge buildup.
2. Chemical Flush: Insist on a non-acidic, EPA-approved biocide and detergent flush. This is circulated through the entire chilled water system to break down the biofilm—this is critical and often skipped.
3. Mechanical Agitation: The drain pan must be manually scrubbed, not just wiped. The evaporator coils should be agitated with a soft brush during cleaning to dislodge stubborn growth.
4. Post-Remediation Verification: Ask for a post-cleaning swab or air test to confirm the microbial count is within Dubai Municipality's acceptable thresholds for indoor air quality.

Many general HVAC technicians aren't certified for this level of bioremediation. For a persistent issue in a Jumeirah villa, the problem is likely severe. I strongly recommend a professional mold inspection from a specialist to assess the full extent and provide a certified clearance report.

Call our team at 800-MOLDS (800-66537) for a proper assessment. We use thermal imaging and particle counters to pinpoint the contamination source and guarantee the remediation is done to Dubai standards.
Posted by Sani Admin
Answered on March 30, 2026 10:21 pm