Furnace-mounted humidifiers create moisture to increase humidity when the furnace blower is on. They are connected to a water supply and don't need to be refilled. They also require very little maintenance. However, they use more water than the reservoir style.
Reservoir-style units are also connected to a water supply, but because they store water they are more vulnerable to bacteria growth than flow-through units. However, bacteria growth can be curbed with an anti-bacterial treatment. If you need increased humidity in only one area of the house, we recommend that you supplement the humidity in that area using a free-standing portable or console style humidifier.