Any hints of musty odor coming from your cooling ducts?

Have you recently turned on your air conditioner in your home and noticed a musty or moldy smell?  So North Texas has a cooling season and a heating system, and these can be months apart or even in the same week. But the condition described here most often occurs when the cooling is intermittent and there are problems in your system from lack of attention and design defects. You might have the conditions right for a biological invasion of mold.

There a a couple different ways you can get mold in your duct system.

First, the filter system should keep your evaporator coils clean. Unless your system allows leakage around the filter; the filter does not fit tightly in the filter frame, or the door access leaks and the vacuum created by the blower lets ambient dust and dirt and organic matter to bypass the filters. This coupled with a wet evaporator coil, which is how your HVAC cools air can create the conditions for mold growth. A crapped up evaporator impedes your system from doing good work, and overworks your blowers and compressors. And can create conditions for mold. Wondering what an evaporator coil is? Want to know more about keeping system clean? We talk about these issues here. LINK

Now clogged and forgotten filters happen often and need immediate correction. Filters in air handlers can be forgotten, get clogged, create air blockage and upset the balance of the system and create the conditions for mold growth. Make sure you are checking the filters on a regular order. Check out the list of mandatory HVAC system checks that depend on you. 

Second, HVAC system ducts can create conditions for mold growth. Home construction in Texas saves money up front by stuffing all the duct work and often the air handler in the attic. Attics in North Texas are hostile, gaining heat in summer through which cool air in ducts runs a gauntlet. But the condition to create mold in ducts is in the heating season where a poorly insulated section of ducting allows heated air to cool and reach dew point. The cold attic at ambient temperature coupled with poorly insulated sections of ducting can create the conditions for mold. Mold growth is a complex enterprise, but mold shows perseverance, and if the conditions are right….  more on mold growth here. 

Duct systems are complex and essential to a properly working HVAC system. Yet, the ducts are often ignored and the air handler held responsible for all areas of discomfort.

Here is more information on potential duct issues.

Mold odors are a harbinger to unhealthy air. More info here.

Make sure you turn to fundamental solutions. Duct cleaning is not the answer, although it may play a role; but only if suggested by a reputable HVAC service contractor and only after fundamental issues are solved. They conditions that created the mold must be found and eradicated by proper design and workmanlike execution. Then the clean up can be discussed. Most often, duct cleaning is a profit center for grifters. More on making sure about what you are buying.

Any questions? Comments? Thoughts? Add them below.


Stu Langley

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