More mold! OK. So we explained why mold is a big problem in today’s modern home. If you didn’t see that post, check it out here: http://www.acdoctor.com/blog/simple-leaking-pipe-can-lead-big-longterm-problems/.
Construction materials and methods are organic— no, that’s not a good thing, necessarily, in this context— and so fungi can thrive as soon as the requisite moisture arrives. Which it does, as we described— via a leaking pipe, the aftermath of a rainstorm, a kitchen flood, or any number of other ways.
Because our heating & cooling systems deal with moisture (mostly the removal of it), these systems are prone to collecting water in places where fungi love to grow (dark, uncleaned, dificult-to-reach places). The HVAC system has the potential to spread mold throughout a building.
If you spot mold growing inside of hard ducts such as sheet metal, it’s time to have them cleaned. If there is insulation inside the ducts and the insulation has gotten wet or moldy, it must be replaced [This note from the EPA: There are no antimicrobial products or biocides approved by the EPA for use on lined ductwork.]
Controlling moisture is the best way to keep mold from growing in air ducts. How to do this?
* Tend to any leaks or water damage promptly.
* Make sure that drain pans are tilted and the drain is emptying properly.
* Seal and insulated ducts in unconditioned spaces so moisture can’t enter the system.
* Make sure dehumidification equipment, if it exists, is functional.
* Have carpets, drapes, furniture and other materials dried thoroughly after they’re cleaned.
Any crawl space with a bare earthen floor will wick moisture from the earth into the building. For more from the EPA on dealing with mold, see their service page: http://www.epa.gov/mold/moldcourse/chapter2.html