Aprilaire 800 Whole House Steam Humidifier, High Output Humidifier BUY WITH CONFIDENCE This high output steam humidifier was designed with electrode technology and manufactured in the U.S.A. by Aprilaire  the inventor of the whole home evaporative humidifier, and the leader in indoor air quality solutions FULL COVERAGE up to 6,200 square feet in tightly built homes. Choose from 6 levels of output adding 11.5 to 34.6 gallons of moisture into the air per day based on voltage and installation IDEAL FOR homes in arid, desert climates PURIFIED WATER NOT REQUIRED Electrode technology requires impurities in the water to promote the transfer of electricity. Water filtration is not recommended  minimizing installation complexity and operating costs HUMIDITY FOR HEALTH Aprilaire Humidifiers can help you maintain optimal humidity in your home of 35%  45% which has been shown to reduce the incidence of respiratory infections and symptoms related to allergies and asthma by minimizing the formation of bacteria and viruses, fungi, and dust mites