Aprilaire Fresh, pure air became the top concern of Research Products Corporation over 60 years ago. That’s when we first began to design, develop, manufacture, and distribute quality products which improve the environment by conditioning the air in homes throughout North America. We introduced Aprilaire® humidifiers in 1954 as the first evaporative, flow-through-design humidifiers. Since then, we've added the Aprilaire Automatic Humidifier, Aprilaire High Efficiency Air Cleaner, Aprilaire Zone Control System, Aprilaire Electronic Thermostats and Aprilaire Energy Recovery Ventilator to continue our dedication to both quality manufacturing and more breathable, more healthful air. Visit Aprilaire: http://www.aprilaire.com/