Aprilaire introduced the first evaporative humidifier for forced air furnace systems back in 1954. Since that time, Aprilaire continues to lead the industry in whole home humidification systems. Our evaporative humidifiers work by piping water into the distribution tray located at the top of the humidifier. Natural evaporation takes place, the water is turned to vapor, and the humidified air is circulated throughout your home.