The temperature setting only controls the temperature of the climateline. When the humidifier is set to auto, it will automatically adjust the humidification and heating plate temp to what they claim is the optimal humidity possible while reliably preventing rain out. The higher the temp on the climateline, the higher the humidifier will be able to heat and still not cause rain out. The H5i will also self adjust for relative humidity on auto. If you disconnect the climateline, you will see that you can set the desired humidity level (represented by a water drop) 1 - 6 when you are not using the climateline. When you connect the climateline your climate controls, when set to auto, will self adjust. To be able to manually set humidity with the climateline you need to set it to either "manual" or "patient". Many people are fine with it set to auto. I put mine on "patient" so the controls are out on the main menu and set my humidity to 6 (as high as it will go) and my climateline to 86 deg. (also the highest) because I really like the moist air due to sinus problems and deviated septum. I think they made the auto mode a little too conservative on humi so they could guarantee you won't ever have rain out. I've found that I can leave my humi all the way up as long as I'm using the climateline and it's at 86 deg., but I have pretty dry air in my house because of electric heat.