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How Humid Should My Basement Be?

Basement humidity that's too high can create mildew and mold problems. This is rarely a concern in the winter since the colder air doesn't retain humidity, but during a rainy spring or summer the humidity can spike quickly.

Mildew can hide for years in a basement without being discovered.

Things You Will Need

  • Electronic hygrometer
  • Dehumidifier
  • Fan

Basement humidity that's too high can create mildew and mold problems.  This is rarely a concern in the winter since the colder air doesn't retain humidity, but during a rainy spring or summer the humidity can spike quickly. The basement humidity should be kept at or below about 65 percent during the summer and 30 to 40 percent in cold winter climates, according to Dr.  Kenneth Hellevang from North Dakota State University. There are several ways to help keep it at those levels. 

  1. Set a electronic hygrometer in the basement to measure the air moisture content. Keep a watch on it to see if your home has a problem.
  2. Run a dehumidifier as the best way to remove basement air moisture. A model with a continuous drain never needs emptying, while some models can be set to operate only when the moisture level reaches a predetermined amount.
  3. Provide for air circulation via a table or exhaust fan. Leave room between the walls and the furniture so the air can move freely about the room.

Things You Will Need

  • Electronic hygrometer
  • Dehumidifier
  • Fan

About the Author

Jack Burton started writing professionally in 1980 with articles in "Word from Jerusalem," "ICEJ Daily News" and Tagalong Garden News. He has managed radio stations, TV studios and newspapers, and was the chief fundraiser for Taltree Arboretum. Burton holds a B.S. in broadcasting from John Brown University. He is a 26-year veteran of the U.S. Navy/Navy Reserves and the Navy Seabees.

Photo Credits

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