The Humid-Aire FH-200 humidifier is a whole house humidifier designed to be installed on a forced air heating system for a home or office. Maximum humidifier efficiency depends upon the tightness of your home, the hardness of your water and a variety of external factors. Consult us for the Humid-Aire home humidifier that's best for you. The humidifier filter on your Humid-Aire FH-200 humidifier must be replaced at least once per year for optimum performance and to increase the life of your humidifier and heating equipment.