Recommended Relative Humidity
Recommended relative humidity level.
Relative humidity above 70% (and even lower at special conditions) may for normal living conditions cause condensation on cold surfaces - causing mold, corrosion and moisture related deterioration.
Too low relative humidity may cause problems with static electricity, cracking of paint and shrinkage of wood furniture and wood floors.
For humans relative humidity below 25% feels uncomfortable dry. Relative humidity above 60% feels uncomfortable wet. Human comfort requires the relative humidity to be in the range 25 - 60% RH.