The ideal humidity level for health and comfort is somewhere between 30-50% humidity, according to the Mayo Clinic. Research shows that the ideal relative humidity for your home is between 40%-60% . However, to discourage the growth and spread of mold, levels should be kept below 50% . According to the Environmental Protection Agency, the best indoor relative humidity falls between 30% and 50%, and it should never exceed 60% . The dew point is another factor that affects how "comfortable" it will feel outside. A dew point less than or equal to 55 is dry and comfortable, between 55 and 65 is becoming "sticky" with muggy evenings, and greater than or equal to 65 has lots of moisture in the air.