55UD Flow-Thru Humidifier

Under-Duct Flow-Thru Humidifier with Manual Humidistat

Humidifier for Warm Air Furnaces and High-Efficiency Heating Systems

Skuttle Under Duct Humidifiers are real workhorses that perform well on heat pumps and high-efficiency heating systems. In fact, they are superior to plenum-mount flow-thrus on today’s 90-plus furnaces.

Moisture Output Capacity

Temp (Warm Air Duct) Lbs/Hour Gal/Day
120°F 6.95 20.0
110°F 6.54 18.8
100°F 5.22 15.0

Home/Humidifier Sizing Range

Model Tight House Loose House
Square Feet 4,762 2,174
Cubic Feet 38,095 17,391
NOTE: Ratings and calculations are in compliance with ARI Formula 610.


Product image of 55UD Flow-Thru Humidifier
Sales Literature Owners Manual
How Flow-Thru Humidifiers Work
  • Mountable on horizontal ducts as small as 12” wide and 8” high

  • With normal maintenance, they cause no airflow resistance.

The Model 55UD, along with its connecting water valves, must be turned OFF at the end of each heating season.