MADISON, Wis. - Aprilaire is celebrating the 50th anniversary of the invention of its first evaporative, whole-house, flow-through humidifier - the Model 100.

"With the introduction of the whole-home humidifier in 1954, Aprilaire transformed the HVAC industry by opening the gateway for a whole new category of products for contractors to offer homeowners," said Bruce Darkow, product manager for Aprilaire.

"As far as we can tell, the Model 100 was one of the first indoor air quality [IAQ] accessories available for installation on heating and cooling systems."

Originally designed to compete with plate-type humidifiers, the Aprilaire Model 100 whole-house humidifier incorporated the same basic physics still used in several models of Aprilaire humidifiers today.

This year the company reached another milestone with the introduction of its whole-house dehumidifier at the 2004 Air-Conditioning, Heating, Refrigerating Exposition (AHR Expo) in Anaheim, Calif.

A Little History

  • The first power humidifiers included Models 110 and 112. According to the company, the 110 was last produced in 1995. The 112 was last produced in 1992.

  • These were replaced by the Model 760, which was equipped with a manual control. "We then introduced the Model 760A, which was the Model 760 but with an automatic control," said Darkow. The Model 700 replaced models 110, 112, 760, 760A, and the 768.

  • The company's original by-pass humidifiers were models 220 and 224. The 220 was last produced in 1992. The 224 was last produced in 1993.

  • The Model 440 replaced Chippewa models 220 and 224. The 440 was replaced by the Model 550 (smaller bypass) and 560 (larger bypass). All of these were equipped with the manual control.

  • "In addition to models 550 and 560, we also introduced models 550A and 560A, which were the models 550 and 560 but with an automatic control," Darkow said.

    "The model numbers were then changed from 550A and 560A, to 558 and 568. The Model 600 replaces models 560, 560A, and 568." The Model 558 has been eliminated. The Model 550 is still part of the Aprilaire lineup.

  • The company's first recirculating bypass humidifier was the Model 225, later replaced by the 445. Both were equipped with the manual control. "We also offered the 445A with the automatic control," Darkow said. "This was later changed to Model number 448. The existing Model 448 replaces the Model 445, 445A, and the older 448. The Model 400 replaces this unit."

  • The company's original self-contained unit was the Model 330. It was later replaced by models 350 and 360. "These units are equipped, with and can only be used, with the manual control," said Darkow. "The control that is equipped with the Model 600, 700, and the existing 448 can be wired as an automatic or manual control and is return-duct-mounted only."

    Aprilaire is owned by Research Products Corp. Aprilaire Intelligent Solutions for Indoor Environments is an integrated group of air quality products designed for use with residential and light commercial heating-cooling systems. The humidifier anniversary celebration will continue throughout this year.

    Publication date: 02/23/2004