Musty AC Smell: Evaporator Coil, Condensate Line, Unit Size

Musty AC Smell: Evaporator Coil, Condensate Line, Unit Size

In part one of this two-part blog series, we went over some of the common causes of a musty, mildew-y smell emanating from your outdoor AC unit or any of the other HVAC ducts or vents in your home. This odor, which is easy to identify once you’ve smelled it for the first time, could be due to a few different issues, including potential mold formation, and will often require some basic action taken by you or an HVAC specialist to remedy.

At Airtime Heating & Cooling, we’re here to help. We offer a wide range of HVAC services, including everything from AC repairs and service up through several indoor air quality themes we’re happy to assist you with. What are some of the other minor concerns that might be signaled by a musty or mildew-y odor in your HVAC system, and how can you either avoid or remedy these? Here’s a primer.

Evaporator Coil Issues

One issue that may take place around the AC unit itself involves the evaporator coils, which may freeze if the unit is not properly cared for. During normal operation, this unit absorbs your warm air from indoors, them removes its humidity and cools it before sending it back into your vents – this process requires free-flowing air and also the presence of a quality air filter to trap contaminants.

However, over time, this filter may become blocked or clogged by dirt and debris. This will cause water drops from the indoor air, which is still humid, to collect on your outdoor unit’s evaporator coils, and may lead to this odor you’ve smelled. But as refrigerant continues to move through these coils, it freezes the water that’s dropped onto them – and therefore freezes the coils, as well. Remedies here involve both un-freezing the coils and attending to clogged filter concerns so this doesn’t happen again.

Condensate Line Blockage

Another part of the AC unit is the condensate line, which is a small pipe next to the condenser unit that drains water from the drip pan. A possible concern here due to the moisture content is the buildup of mold, mildew and other forms of sludge – and the best way to prevent these are simply to clean this line regularly. This involves turning off the unit and removing the line from its attachment, then pouring distilled white vinegar in before rinsing after 30 minutes and re-attaching.

Wrong Unit Size

Finally, that mildew-y smell might be coming from an AC unit that’s simply the wrong size. If it’s too large, air will cycle through too quickly and will not be properly dehumidified – this will bring excess moisture and several related risks, including odors forming. If none of the other causes we’ve gone over here are the answer to your musty smell, call one of our HVAC technicians to evaluate the size of your unit.

For more on identifying the causes of a musty smell in your AC unit or HVAC system, or to learn about any of our heating and air services, speak to the staff at Airtime Heating & Cooling today.