Another factor in this discussion that no one has mentioned is a humidifier placed in one room versus a furnace mounted one. When using a room humidifier to try to increase humidity in the whole house, that one room is going to always have a much higher humidity than the rooms farthest away. Hence, you could have serious condensation in one room, while other areas are not a problem. With a furnace mounted one, the humidity is distributed evenly. If the room humdidifer is located near a window, that would make it even worse.