In situations where there are two trunk lines extending from the furnace, is it helpful to install two under duct humidifiers (i.e., one on each line)?
As long as a single 55UD Under Duct Flow-Thru Humidifier or 86UD Under Duct Drum Humidifier can handle the cubic footage of the home, a second unit on a second trunk line is pointless. The reason has to do with the way humidity travels. Humidity always travels through its surrounding gas mixture (in this case, the air in the home) at 25 feet (7.62 meters) per second. If you were to introduce humidity into a 50-by-50-foot (15.24-by-15.24-meter) home, the humidity would take just two seconds to disperse evenly throughout the house.
