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SESK: Stuff Everyone Should Know · sesk.info/home-a-mold-humidity

What indoor humidity does EPA say is ideal for discouraging mold?

30 to 50 percent, and below 60 percent at most.

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  1. 70 to 80 percent
  2. 30 to 50 percent ✔
  3. 5 to 15 percent

Why: EPA suggests keeping indoor humidity below 60 percent, ideally between 30 and 50 percent relative humidity. A moisture or humidity meter costs about $10 to $50.

Huh, didn't know that: Condensation on windows, walls or pipes can be a sign of high humidity.

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References

Answer: 30 to 50 percent. EPA suggests keeping indoor humidity below 60 percent, ideally between 30 and 50 percent relative humidity. A moisture or humidity meter costs about $10 to $50.

  1. EPA: A Brief Guide to Mold, Moisture and Your Home www.epa.gov/mold/brief-guide-mold-moisture-and-your-home
    keep indoor humidity below 60 percent (ideally between 30 and 50 percent) relative humidity
    Checked 2026-10-10.

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