This Flow-Through Furnace Mounted Humidifier from Air King features an 18-gallon output per day and humidifies rooms up to 4800 square feet. The humidifier mounts directly to your furnace and has an outdoor sensor. The humidistat is included. This furnace mounted humidifier has no pans, drums or floats to replace or clean. The flow-through action constantly rinses the evaporator pad, so you don't have to replace it as often. The humidifier has easy left or right ducting.