Humidity settings are highly personal and depend on factors like CPAP air pressure, the temperature and humidity in your bedroom, and individual preferences. Setting the humidifier too low may leave you with a dry mouth and nose, while setting it too high may cause condensation.  A common problem with CPAP humidification is rainout, a term for condensation that forms in a CPAP hose or mask when the temperature of the tubing is lower than that of the humidified air. You can reduce rainout by turning down the humidifier temperature, using heated tubing, or using a cover to insulate the tubing.