The Skuttle 592-22 humidifier is a whole house humidifier designed to be installed on a forced air heating system for a home or office. This model is designed to be installed on a gas or electric furnace. Do NOT install it on a heat pump. Heat pumps require the model 592-9. 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 Skuttle home humidifier that's best for you.