You need a humidifier which makes steam to get your humidity in the over 40% range in addition to a correct humidistate. There are several manufactures of these units. They are more expensive and use a lot more power to boil water into steam but they work. You may need a commercial model if you want to do your whole house. These will operate well without your furnace having to be on, just your blower and are set up to turn the blower on without calling for the furnace unless the temperature drop calls for it.