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Independent public directory · Data checked October 2, 2026 · Not a government agency

Humidity, mold, and your air

  • Below 60%indoor humidity, EPA says1
  • 30 to 50%ideal, EPA says1

EPA: "If possible, keep indoor humidity below 60 percent (ideally between 30 and 50 percent) relative humidity." "Relative humidity can be measured with a moisture or humidity meter, a small, inexpensive ($10-$50) instrument available at many hardware stores."1

Mold needs moisture

EPA: "The key to mold control is moisture control." "There are many types of mold, and none of them will grow without water or moisture."1

Hidden mold

EPA: "You may suspect hidden mold if a building smells moldy, but you cannot see the source, or if you know there has been water damage and residents are reporting health problems."1 More on smells: a smell in the house.

If you find mold

EPA: "If mold is a problem in your home, you should clean up the mold promptly and fix the water problem."1 When is a cleanup finished? One of EPA's signs: "Visible mold and moldy odors should not be present."1

Airthings View Plus showing radon and carbon dioxide readings

A monitor for the air inside

Airthings View Plus: $329.99
Price checked October 1, 2026

Airthings says:2

  • "Indoor humidity above 60% encourages mold growth and dust mites, while levels below 30% cause dry skin and throat irritation."

Check price at Airthings

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Sources

  1. EPA, A Brief Guide to Mold, Moisture and Your Home, checked October 4, 2026
  2. Airthings, View Plus product page, checked October 4, 2026

Health facts on this page come from the agencies linked here. About this directory.