Aprilaire Model 400 Whole-House Humidifier

Automatic WATER SAVER Furnace Humidifier. The Model 400 is a drain-free humidifier, featuring evaporative technology to minimize water use.

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. The water is uniformly distributed across the width of the tray and through a scientifically designed system of outlets. It flows by gravity over the water panel evaporator. Dry, hot air from the HVAC system is moved through the moisture-laden water panel evaporator. Natural evaporation takes place, the water is turned to vapor, and the humidified air is circulated throughout your home.

Included in the box: Installation instructions and template, humidifier with built-in bypass damper, 24 VAC transformer, automatic digital humidifier control, and outdoor temperature sensor, saddle valve, solenoid valve, and water panel.

Model 400 features:

  • BUY WITH CONFIDENCE This humidifier was designed 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
  • CONSERVES WATER using a unique evaporation process that also eliminates the need for a floor drain
  • FULL COVERAGE up to 2,500 square feet in average constructed homes* with a capacity of 17 gallons per day
  • AUTOMATIC HUMIDIFIER with dual sensors to monitor and respond to both outdoor temperature and indoor relative humidity to deliver optimum humidity 24/7 throughout the home – simply set it and forget it
  • CONVENIENT DIGITAL CONTROL shows percent humidity, lights indicate humidifier is running, when to change the water panel, when service is needed, and Blower Activation switch sets humidifier to run continually, or only when the furnace runs
  • HUMIDITY FOR HEALTH Aprilaire Humidifiers can help you maintain the optimal humidity in your home between 40% – 60% minimizing the formation of bacteria, dust mites, fungi, and viruses. This helps reduce the incidence of respiratory infections and symptoms related to allergies and asthma. In addition, you’ll feel more comfortable while also preserving items in your home susceptible to damage from changing humidity or dry conditions.