When an unpleasant musty odor wafts from your air ducts or peculiar discolorations mar your air vents, it's a telltale sign of active mold growth.
The presence of mold in air conditioning units and air ducts can be attributed to various factors:
Hot, Humid Climates:
In sweltering, humid summer climates, as we cool the air, we simultaneously extract moisture from it. Ideally, this moisture is collected at the AC coil in the drain pan and routed outdoors.
Aging or Inefficient HVAC Units:
Older or inefficient HVAC units often struggle to effectively dehumidify the air when faced with extreme temperatures and high humidity levels. They simply cannot keep pace with the demand, allowing indoor humidity to remain elevated, which fosters mold growth.
AC Coil Neglect:
When routine HVAC maintenance is neglected, the AC coil can accumulate dust and debris, becoming a nourishing source for mold. As cool water drips onto the dust and debris, mold takes root and spreads. The most frequently encountered mold in HVAC units is Cladosporium, which proliferates rapidly and emits musty odors. Cladosporium has been linked to allergies, asthma symptoms, skin infections, eye and sinus issues, and, in rare cases, even brain infections.
Blocked Drain Lines:
Failure to clean condensation drain lines annually can result in clogs, causing water backup within the HVAC unit. Since most HVAC units feature insulation at their base, when this insulation becomes saturated, it can take months to dry out. Within just a week, mold can flourish and expand. Typically, mold first thrives on the moist insulation, then spreads to the AC coil and fan unit.
Humidifiers:
While humidifiers offer relief during dry winter months, they can lead to problems when forgotten or left running in the summer. Neglected humidifiers continuously add moisture to already humid air, fostering extensive mold growth in both the HVAC unit and the ducts where humidifiers are installed.
Location Matters:
The placement of HVAC units and ductwork can also play a role. Units or ducts situated in damp crawl spaces or wet basements are susceptible to mold growth, both externally and internally.
Mold Inspection and Remediation:
If you notice mold on an HVAC register, it often indicates a more extensive hidden moisture issue. Mold spreads swiftly, so if mold is present on an air register, it's wise to conduct a comprehensive mold inspection. This inspection should cover the HVAC unit, drain pan, AC coil, fan, and the surrounding areas like crawlspaces, basements, or attics. Since mold typically indicates a broader concern, a thorough examination of the entire home is recommended. For example, a vent located too close to a shower may combine steam and cold air condensation, creating ideal conditions for mold growth.
In most cases, mold on an air vent signifies a more significant moisture problem, with deeper mold growth inside the HVAC unit and/or air ducts.
If your air ducts contain internal insulation or are made of fiberboard (compressed fiberglass) and are contaminated with mold, they may need replacement, as removing mold and applying a mold preventative sealant to this type of ducting is challenging. Exceptions may apply when ductwork is inaccessible or as a temporary solution until new ductwork can be installed.
If the issue is due to the HVAC unit and ducts being located in a damp environment, resolving the underlying water and moisture problem is essential before tackling mold cleanup.
In any mold situation, addressing water and moisture issues is key to preventing future mold recurrence. If you suspect mold problems within your HVAC unit or ductwork, don't hesitate to reach out to Building Performance Solution! for assistance.