Red flakes of tissue-like material are blowing out of our heating system's ducts. Any idea what this is? What can be done to prevent it?

Asked by Don E
Wapakoneta, OH

Last year we experienced "Dirty Socks Syndrome" in our home and a specially coated heating coil was installed which took care of the objectionable odor. Later in the heating season, red flakes of tissue-like material started blowing out of the air ducts. The contractor cleaned up the unit and had the material analyzed. The analysis indicated the material was an algae. We thought the problem was fixed, but with the start of this year's heating season, the red flakes are blowing out again, worse than last year. The larger flakes are one-and-a-half inches long and three-quarters of an inch wide. Any idea what this is and what can be done to prevent it? Could it be a health issue?



Check the condensation pan and drain for the cooling coils. The pan and drain may not be draining properly, allowing the water to become stagnant and algae to form.

When the heating season begins, the water is evaporated and the algae flakes off, exiting through the vents into your house.

For more information:

Read Harold Remlinger's Q&A "What can be done to help a person who is allergic to dust from a crawlspace-mounted central furnace?"

Tagged In: home air quality, heating cooling

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