are automatic now, meaning they automatically adjust humidity percentage based on outside temperature. The control has levels one through seven with level one being low humidity and seven being high humidity. Start in the middle and adjust accordingly until you find the correct setting for your comfort. Once you find the correct setting, it will automatically adjust and you shouldn’t need to touch the control again. The digital readout on the control will read the relative humidity in the house, not the percentage of humidity. The percentage of humidity will go up when the outside temperature is warmer (35 percent at 40 degrees Farenheit) and will go down (10 percent at -10 degrees Farenheit) when the outside temperature is lower. Examples of percentage versus temperature are estimates.